Discussion:
[Bug 524281] Re: Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo with 1 core disabled in BIOS
(too old to reply)
Jeffrey Baker
2010-03-01 06:07:14 UTC
Permalink
Confirmed on a ThinkPad X61. This is new in Lucid Alpha 3, wasn't there
in Alpha 2.

** Changed in: linux (Ubuntu)
Status: New => Confirmed
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo with 1 core disabled in BIOS
https://bugs.launchpad.net/bugs/524281
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Jeffrey Baker
2010-03-01 06:11:41 UTC
Permalink
I should also mention that I don't have a core disabled in the BIOS, I
am using both cores. It shouldn't matter.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo with 1 core disabled in BIOS
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Jeffrey Baker
2010-03-01 06:25:31 UTC
Permalink
# powertop -d
PowerTOP 1.12 (C) 2007, 2008 Intel Corporation

Collecting data for 15 seconds


Your CPU supports the following C-states : C1 C2 C3 C4
Your BIOS reports the following C-states : C1 C2 C3
Cn Avg residency
C0 (cpu running) (31.1%)
C0 0.0ms ( 0.0%)
C1 mwait 0.0ms ( 0.0%)
C2 mwait 0.1ms ( 0.0%)
C3 mwait 4.8ms (68.9%)
P-states (frequencies)
Turbo Mode 15.7%
2.00 Ghz 0.1%
1.60 Ghz 0.1%
1200 Mhz 0.2%
800 Mhz 84.0%
Disk accesses:
The application 'firefox-bin' is writing to file 'sessionstore-1.js' on /dev/sda1
The application 'firefox-bin' is writing to file 'sessionstore-1.js' on /dev/sda1
The application 'firefox-bin' is writing to file '_CACHE_001_' on /dev/sda1
The application 'firefox-bin' is writing to file '_CACHE_001_' on /dev/sda1
The application 'firefox-bin' is writing to file '_CACHE_001_' on /dev/sda1
Wakeups-from-idle per second : 145.1 interval: 15.0s
no ACPI power usage estimate available
Top causes for wakeups:
71.1% (296.3) [kernel scheduler] Load balancing tick
7.7% ( 32.2) [Rescheduling interrupts] <kernel IPI>
3.7% ( 15.3)D firefox-bin
3.9% ( 16.3) [acpi] <interrupt>
3.3% ( 13.9) [iwlagn] <interrupt>
2.5% ( 10.5) [i915 at pci:0000:00:02.0] <interrupt>
2.3% ( 9.5) PS/2 keyboard/mouse/touchpad interrupt
1.0% ( 4.3) Xorg
1.0% ( 4.0) [kernel core] usb_hcd_poll_rh_status (rh_timer_func)
0.9% ( 3.6) [ahci] <interrupt>
0.6% ( 2.6) [kernel core] hrtimer_start (tick_sched_timer)
0.3% ( 1.2) gnome-terminal
0.2% ( 1.0) gvfs-afc-volume
0.2% ( 0.7) top
0.2% ( 0.7) compiz
0.1% ( 0.5) python
0.1% ( 0.4) update-notifier
0.1% ( 0.3) [eth1] <interrupt>
0.1% ( 0.3) events/0
0.1% ( 0.3) [kernel core] inc_rt_group (sched_rt_period_timer)
0.1% ( 0.3) clock-applet
0.0% ( 0.2) gnome-settings-
0.0% ( 0.2) indicator-apple
0.0% ( 0.2) gnome-panel
0.0% ( 0.2) gnome-power-man
0.0% ( 0.2) bdi-default
0.0% ( 0.2) flush-8:0
0.0% ( 0.2) rtkit-daemon
0.0% ( 0.1) [kernel core] sk_reset_timer (tcp_delack_timer)
0.0% ( 0.1) [kernel core] arm_supers_timer (sync_supers_timer_fn)
0.0% ( 0.1) NetworkManager
0.0% ( 0.1) rmmod
0.0% ( 0.1) sshd
0.0% ( 0.1) [kernel core] neigh_add_timer (neigh_timer_handler)
0.0% ( 0.1) khungtaskd
0.0% ( 0.1) [kernel core] add_timer (addrconf_verify)
0.0% ( 0.1) events/1
0.0% ( 0.1) ssh-agent
0.0% ( 0.1) gnome-volume-ma
0.0% ( 0.1) [kernel core] add_timer (sta_info_cleanup)
0.0% ( 0.1) kerneloops
0.0% ( 0.1) [kernel core] fib6_run_gc (fib6_gc_timer_cb)
0.0% ( 0.1) rsyslogd

A USB device is active 100.0% of the time:
USB device 3-1 : BCM2045B (Broadcom Corp)

Suggestion: Enable USB autosuspend for non-input devices by pressing the
U key


Suggestion: increase the VM dirty writeback time from 5.00 to 15 seconds with:
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs
This wakes the disk up less frequently for background VM activity

Suggestion: Enable SATA ALPM link power management via:
echo min_power > /sys/class/scsi_host/host0/link_power_management_policy
or press the S key.

The program 'firefox-bin' is writing to file '_CACHE_001_' on /dev/sda1.
This prevents the disk from going to powersave mode.

The program 'firefox-bin' is writing to file '_CACHE_001_' on /dev/sda1.
This prevents the disk from going to powersave mode.

The program 'firefox-bin' is writing to file '_CACHE_001_' on /dev/sda1.
This prevents the disk from going to powersave mode.

The program 'firefox-bin' is writing to file 'sessionstore-1.js' on /dev/sda1.
This prevents the disk from going to powersave mode.

The program 'firefox-bin' is writing to file 'sessionstore-1.js' on /dev/sda1.
This prevents the disk from going to powersave mode.

Recent USB suspend statistics
Active Device name
0.0% USB device 3-2 : Biometric Coprocessor (STMicroelectronics)
100.0% USB device 3-1 : BCM2045B (Broadcom Corp)
0.0% USB device usb6 : UHCI Host Controller (Linux 2.6.32-14-generic uhci_hcd)
0.0% USB device usb5 : UHCI Host Controller (Linux 2.6.32-14-generic uhci_hcd)
0.0% USB device usb4 : UHCI Host Controller (Linux 2.6.32-14-generic uhci_hcd)
100.0% USB device usb3 : UHCI Host Controller (Linux 2.6.32-14-generic uhci_hcd)
0.0% USB device usb2 : EHCI Host Controller (Linux 2.6.32-14-generic ehci_hcd)
0.0% USB device usb1 : EHCI Host Controller (Linux 2.6.32-14-generic ehci_hcd)

Recent audio activity statistics
Active Device name
0.0% hwC0D0 Analog Devices AD1984

Recent SATA AHCI link activity statistics
Active Partial Slumber Device name
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo with 1 core disabled in BIOS
https://bugs.launchpad.net/bugs/524281
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Jeffrey Baker
2010-03-01 06:30:10 UTC
Permalink
Notably, events/0 and events/1 are getting tons of CPU time:

# ps -fe | grep events
root 9 2 5 20:58 ? 00:04:46 [events/0]
root 1016 1 0 20:58 ? 00:00:00 acpid -c /etc/acpi/events -s /var/run/acpid.socket
root 3473 2 49 22:19 ? 00:05:16 [events/1]
root 4370 4289 0 22:29 pts/1 00:00:00 grep events
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo with 1 core disabled in BIOS
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-03-01 06:47:34 UTC
Permalink
Rephrasing the summary.
Indeed the problem is much worse with the 2 cores enabled, the report is just that i was expecting no wake up at all with only 1 core.
nosmp, noapic and nolapic made no difference. Actually will all of these enabled the system was bogged down with not apparent explanation.

** Summary changed:

- Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo with 1 core disabled in BIOS
+ Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
https://bugs.launchpad.net/bugs/524281
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davidb
2010-03-01 09:54:17 UTC
Permalink
I'd just like to report that I am having the same issue. I also have a
Thinkpad x61, Core2. I just upgraded to Lucid a few hours ago. I tried
disabling a core and saw the same problem. As Fl?vio wrote, I would have
expected that to significantly reduce the number of wakeups. If I can
be of any help in debugging this let me know.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
https://bugs.launchpad.net/bugs/524281
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Ryan Kavanagh
2010-03-10 02:57:00 UTC
Permalink
Linked to Debian bug 521944 based on comment 84 . I can confirm this
happens under Ubuntu Lucid with an Intel Atom N280, so I don't think
this is restricted to Core 2 Duo.

** Bug watch added: Debian Bug tracker #521944
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521944

** Also affects: linux-2.6 (Debian) via
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521944
Importance: Unknown
Status: Unknown
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
https://bugs.launchpad.net/bugs/524281
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Bug Watch Updater
2010-04-01 00:12:14 UTC
Permalink
** Changed in: linux-2.6 (Debian)
Status: Unknown => Incomplete
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
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Leif Walsh
2010-04-01 02:26:18 UTC
Permalink
What is incomplete about this bug? I am getting 500 wakeups
consistently from this load balancing tick, on an x200s, with latest
Lucid.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-04-01 04:36:36 UTC
Permalink
Funny how the comments in the Debian tracker suggests says "worksforme" and suggests powertop is outdated without any data.
Latest powertop here lists this:

Top causes for wakeups:
44,1% (199,2) <kernel core> : hrtimer_start_range_ns (tick_sched_timer)
26,5% (119,6) firefox-bin : hrtimer_start_range_ns (hrtimer_wakeup)
12,0% ( 54,2) <interrupt> : extra timer interrupt
7,8% ( 35,2) <interrupt> : ath, HDA Intel
1,8% ( 8,0) <kernel core> : usb_hcd_poll_rh_status (rh_timer_func)
1,3% ( 6,0) <interrupt> : ata_piix, ata_piix, uhci_hcd:usb5, uhci_hcd:
usb7 Segmentation fault (core dumped)

And yes, it coredumps.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-04-01 06:30:23 UTC
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Leif: what was marked incomplete is the Debian bug entry.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
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Alexander Konovalenko
2010-04-21 12:42:45 UTC
Permalink
I observe this problem on a single-core Intel Atom Z520 CPU with
HyperThreading enabled using Ubuntu 10.04 Lucid beta 2. Based on that
and on comment #8 here, I edited the bug summary to remove the CPU-
specific part.

** Summary changed:

- Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even if only 1 core enabled (1 disabled in BIOS)
+ Tens of wakes per second in "[kernel scheduler] Load balancing tick"
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick"
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-04-21 16:22:44 UTC
Permalink
Problem is I reported this bug because I don't expect "load-balancing"
wake-ups on a single-cpu setup. I don't know what is the expected number
of wake-ups with multiple CPUs or HyperThreading. If you can reproduce
the problem of running without HyperThreading, then maybe this is the
same bug or related.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-04-21 16:27:07 UTC
Permalink
It would be nice to know if this (apparent) bug also occurs on non-Intel
CPUs...
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-04-21 16:36:17 UTC
Permalink
Similar test-case on a Athlon64 cpu shows much lower wake-ups:

Top causes for wakeups:
38.3% (170.0)D firefox-bin
22.4% ( 99.4) pulseaudio
13.8% ( 61.2) [nvidia] <interrupt>
10.8% ( 48.0) PS/2 keyboard/mouse/touchpad interrupt
7.8% ( 34.5) [kernel scheduler] Load balancing tick
2.5% ( 11.3) [pata_via] <interrupt>


** Summary changed:

- Tens of wakes per second in "[kernel scheduler] Load balancing tick"
+ Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled

** Tags added: upstream
** Tags removed: needs-upstream-testing
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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lukefeil
2010-04-22 14:15:12 UTC
Permalink
Similiar on a ASUS 1005PE with a Intel N450

Top causes for wakeups:
42.9% (263.6) [kernel scheduler] Load balancing tick
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Andrew Henry
2010-05-03 12:01:14 UTC
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I had a HP laptop with Intel Core 2 Duo 7200 and this was never an
issue. With Ubuntu 10.04 on a Thinkpad Edge 13 with Intel Core2Duo CULV
CPU this is an issue.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Leif Walsh
2010-05-03 16:12:12 UTC
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Is there any way to just turn off load balancing? I'd be eager to
sacrifice a little performance for a large (almost 100%) gain in battery
life.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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permalloy
2010-05-03 23:20:52 UTC
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Eventually bug 552020 is a duplicate of this one ?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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mihai007
2010-05-05 22:08:26 UTC
Permalink
dell xps m1330, intel t8300 on ubuntu final 10.04 gives:

Top causes for wakeups:
50.6% ( 63.5) [kernel scheduler] Load balancing tick
12.1% ( 15.1) [ata_piix] <interrupt>
10.7% ( 13.4) [iwlagn] <interrupt>
7.1% ( 8.9) [extra timer interrupt]
4.0% ( 5.0) syndaemon
1.6% ( 2.0) [nvidia] <interrupt>

This problem is huge, 50% of cpu wakeups!?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Andrew Henry
2010-05-06 08:51:48 UTC
Permalink
In post #17 I said I had a HP that I never had an issue with. I
didn't...with Ubuntu 9.10. I did a fresh install of 10.04 and have
exactly the same issue. Different CPU, different wireless adapter etc.
Obviously, this is a kernel issue and not hardware specific.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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verwa
2010-05-07 00:27:32 UTC
Permalink
Similiar on a ASUS V1SN Intel Core 2 Duo T7700 (ubuntu 10.4)

Top causes for wakeups:
47.9% ( 63.5) [kernel scheduler] Load balancing tick
12.2% ( 15.1) [ata_piix] <interrupt>
9.7% ( 13.4) [iwlagn] <interrupt>
8.1% ( 8.9) [extra timer interrupt]

---
+ acpi errors

UBUNTU kernel: [ 0.186131] ACPI Error: ACPI path has too many parent prefixes (^) - reached beyond root node (20090903/nsaccess-429)
..
UBUNTU kernel: [ 0.222562] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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lores
2010-05-07 20:16:08 UTC
Permalink
Same problem here: HP 6720s Intel(R) Pentium(R) Dual CPU T2370, Ubuntu
10.04 LTS
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Pawel
2010-05-08 09:16:58 UTC
Permalink
It seems the Phoronix does confirm this issue:

http://www.phoronix.com/scan.php?page=article&item=linux_windows_part2&num=1
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Andrew Henry
2010-05-08 09:37:49 UTC
Permalink
Post by Pawel
http://www.phoronix.com/scan.php?page=article&item=linux_windows_part2&num=1
Thats general power consumption isn't it? They compare graphics card
drivers and power consumption...I do not see any mention of this
particular issue with kernel tick wakeups?

--Andrew
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Michael Christensen
2010-05-08 09:40:25 UTC
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I can confirm this bug on a Core 2 Duo (E6500) and a Pentium D (standard D, not Extreme). Tested with Powertop 1.12. Seems to wake up more under load and wake up less when idle.
Both with Lucid installed (clean installs), fully updated.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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stephen
2010-05-08 10:07:04 UTC
Permalink
Same issue for my Lenovo T400 with Core 2 Duo (P8400),
a brief description of my case is posted here
http://ubuntuforums.org/showthread.php?t=1390055#7

There was a daily update today ... my kernel was just updated to
2.6.32-22, but its appetite on power doesn't change at all ... :(
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Michael Christensen
2010-05-08 18:42:55 UTC
Permalink
I have tested the following boot options adding "idle=halt" and
"processor.max_cstate=1" or cstate=2, not adding all at the same time
but one after the other. None of the options aren't fixing the wakeups
on a Core 2 Duo (E6500) or on a Pentium D (both desktop PCs).

This is what is looks like in Powertop when scrolling a page in Firefox:
Top causes for wakeups:
42,3% (115,9) [kernel scheduler] Load balancing tick

This is what it looks like when idle:
8,2% (7,0) [kernel scheduler] Load balancing tick
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Andrew Henry
2010-05-09 14:21:04 UTC
Permalink
Post by Michael Christensen
42,3% (115,9) [kernel scheduler] Load balancing tick
8,2% (7,0) [kernel scheduler] Load balancing tick
Im getting min 25% on Load balancing tick even when idle. In fact, it
decreases when im actively using the CPU!
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-05-09 15:51:37 UTC
Permalink
We're going nowhere with this bug, we didn't even get word on whether this is expected or a powertop bug (the discussion in debian doesn't hold up) or whatever.
Since this happens is mainstream kernels, I guess somebody will have to get the balls to post to LKML or the kernel bugzilla 8-)
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Michael Livshin
2010-05-10 13:33:22 UTC
Permalink
LKML knows, there's even a patch somewhere:
http://lkml.org/lkml/2010/5/9/20
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Luca Aluffi
2010-05-12 08:28:42 UTC
Permalink
Maybe the problem is wider as it extends to intel atom too: here is my
N270 from ASUS 1201NL:

Wakeup-da-idle al secondo: 130,6 intervallo: 5,0s
Utilizzo energetico (stima ACPI): 9,4W (2,9 ore)

Cause principali di wakeup:
22,0% ( 38,0) [kernel scheduler] Load balancing tick
13,7% ( 23,6) [ath9k] <interrupt>
13,0% ( 22,4) firefox-bin
12,2% ( 21,0) [extra timer interrupt]
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Flávio Etrusco
2010-05-12 13:13:00 UTC
Permalink
The post(s) linked by Michael clearly show this is a general problem
with multi-core, not specific to any CPU model. See:
http://lkml.org/lkml/2010/4/26/249
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Michael Livshin
2010-05-12 19:30:45 UTC
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FWIW, the patch I linked to (which I just got around to actually trying)
doesn't seem to help on my netbook at all.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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bornagainpenguin
2010-05-14 01:21:15 UTC
Permalink
I've had some success Daniel Hollocher's linux-ck ppa:
https://launchpad.net/~chogydan/+archive/ppa

It doesn't fix everything, but the BFS making such a difference does
make it clear this is a kernel issue and not just a few of us having
strange hardware...

--bornagainpenguin
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Andrew Henry
2010-05-14 09:04:43 UTC
Permalink
so in all liklihood, were going to have to shut up and put up until next
ubuntu release when we get a new kernel? or is there any chance whatsoever
that this will be backported??

On 14 May 2010 03:21, bornagainpenguin <bornagainpenguin at gmail.com>
https://launchpad.net/~chogydan/+archive/ppa<https://launchpad.net/%7Echogydan/+archive/ppa>
It doesn't fix everything, but the BFS making such a difference does
make it clear this is a kernel issue and not just a few of us having
strange hardware...
--bornagainpenguin
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Bartosz Skowron
2010-05-17 13:29:06 UTC
Permalink
Can't believe this bug is for months...
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Michael Christensen
2010-05-17 14:01:12 UTC
Permalink
I have installed two mainline kernels (http://kernel.ubuntu.com/~kernel-
ppa/mainline/), .31 & 33, just to see if those kernels made any change
in the number of wakeup calls. Both kernels had about the same number of
wakeups as the Lucid kernel (.32), which led me to wonder whether or not
this could be an userspace bug.

Both kernels made Powertop report :
28,1% ( 7,2) [kernel scheduler] Load balancing tick
27,7% ( 7,1) [kernel core] hrtimer_start (tick_sched_timer)

The fact of the mather is that mainline kernels (at least the ones from the ppa) are not making things better.
Luckily kernel developer Suresh Siddha is working on a patch, that simply has to be backported to Lucid.

These kernel wakeups have to be sorted out, since they are one of the
reasons why Linux power consumption is much higher than on other
platforms.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Kimmo Ahola
2010-05-18 08:24:42 UTC
Permalink
Is there a workaround? Currently my laptop is burning my legs off..

Here's my output of "sudo powertop -t60 -d"


** Attachment added: "Output of "sudo powertop -t60 -d""
http://launchpadlibrarian.net/48645239/powertop.txt
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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skhawam
2010-05-18 09:21:06 UTC
Permalink
Was having this problem as well on my Dell Mini 10v.

Seems like a kernel patch has been posted yesterday:

http://lkml.org/lkml/2010/5/17/350
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Rocko
2010-05-20 13:04:36 UTC
Permalink
I applied that patch to the 2.6.34 amd64 kernel and it does reduce the
load balancing wakeups somewhat on my dual core PC. It went from around
50 per second to 35 after the patch (and that's running Skype and
iwlagn, which average 10 and 15 wakeups per second respectively - the
load balancing wakeups are higher when more things are running: when I
am not running X, the load balancing wakeups are much fewer (under 10)).

I also tried compiling a 2.6.34 kernel *without* multi-core support for
my 32 bit single core PC, and it does reduce the number of load
balancing wakeups (although to my surprise they still happen).

@Fl?vio Etrusco (comment 15): it looks like your nvidia driver is
causing a lot of wakeups, which you can fix with the xorg.conf option:

Option "OnDemandVBlankInterrupts" "True"

and if you're worried about power usage, the nvidia driver defaults to
max performance, which means max power usage. You can put an entry in
xorg.conf that makes it reduce performance (and power) when on battery
but still give max performance on AC for gaming, etc (see eg
http://linux.aldeby.org/nvidia-powermizer-powersaving.html for details).
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Orcie
2010-05-20 13:16:54 UTC
Permalink
Can someone give me a hand with applying the patch, please?
Post by Rocko
I applied that patch to the 2.6.34 amd64 kernel and it does reduce the
load balancing wakeups somewhat on my dual core PC. It went from around
50 per second to 35 after the patch (and that's running Skype and
iwlagn, which average 10 and 15 wakeups per second respectively - the
load balancing wakeups are higher when more things are running: when I
am not running X, the load balancing wakeups are much fewer (under 10)).
I also tried compiling a 2.6.34 kernel *without* multi-core support for
my 32 bit single core PC, and it does reduce the number of load
balancing wakeups (although to my surprise they still happen).
@Fl?vio Etrusco (comment 15): it looks like your nvidia driver is
Option "OnDemandVBlankInterrupts" "True"
and if you're worried about power usage, the nvidia driver defaults to
max performance, which means max power usage. You can put an entry in
xorg.conf that makes it reduce performance (and power) when on battery
but still give max performance on AC for gaming, etc (see eg
http://linux.aldeby.org/nvidia-powermizer-powersaving.html for details).
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Confirmed
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load
balancing tick" task, and above 200 when there's any little load, running on
a Core 2 Duo processor (T6500) with a single core enabled (multicore
disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters
and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
USER PID ACCESS COMMAND
/dev/snd/controlC0: etrusco 1606 F.... pulseaudio
etrusco 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
Mixer name : 'Realtek ALC269'
Components : 'HDA:10ec0269,1b0a4009,00100004
HDA:11c11040,1b0a4007,00100200'
Controls : 19
Simple ctrls : 11
Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
Mixer name : 'ATI R6xx HDMI'
Components : 'HDA:1002aa01,00aa0100,00100100'
Controls : 4
Simple ctrls : 1
Simple mixer control 'IEC958',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic
root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1
acpi_osi=linux radeon.blacklist=yes
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Rocko
2010-05-21 01:33:58 UTC
Permalink
@Orcie: Well, applying the patches was slightly complicated, especially
as one of the patches didn't work, so I had to edit a file by hand. But
if you're game to try, I created a thread for it at:

http://ubuntuforums.org/showthread.php?p=9334524#post9334524
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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bornagainpenguin
2010-05-25 00:28:45 UTC
Permalink
Hmmm...the Canonical developers could've fixed this bug, the systemtray
icon background bug, several other major bus that plague Lucid, showing
they actually do give a flying Shuttleworth about their users...or they
could pull at their roots and fap to Windicators...

Guess which one they chose to do?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Brian Rogers
2010-05-25 07:00:51 UTC
Permalink
This is a kernel bug that needs to be (and is being) fixed by upstream
kernel developers.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Leif Walsh
2010-05-25 07:47:43 UTC
Permalink
How soon after this patch gets accepted do you think we can expect a
backport? Anything I can do to make that estimate shorter?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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alx5000
2010-05-25 08:33:01 UTC
Permalink
Brian Rogers #45
This is a kernel bug that needs to be (and is being) fixed by upstream kernel developers.
I'm aware of that, but in the meantime, I'd rather be able to work on my
laptop for longer than an hour, and without burning my legs off.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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bornagainpenguin
2010-05-27 03:05:09 UTC
Permalink
Post by alx5000
I'm aware of that, but in the meantime, I'd rather be
able to work on my laptop for longer than an hour,
and without burning my legs off.
LOL! "Ubuntu: Upstream will get to it eventually..." was there a motto
change recently I was not aware of? What happened to "Ubuntu: Linux for
Human Beings" that one was good, back when it was accurate! Does
Canonical actually do anything any more other than make themes and re-
implement failed window controls from the 90s?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Brian Rogers
2010-05-27 03:32:41 UTC
Permalink
If somebody has a fix, it needs to be sent upstream to be vetted and
committed anyway. It's good to do quality control before distributing an
update to everyone that only some people will need.

Also, it isn't a matter of "upstream will get to it eventually". There
is already a patch. I plan to set up a PPA with the patch soon, so
people can easily try it out. I'm not sure if this will get backported
to stable, since it's a change to how the scheduler works. Somebody will
have to inquire upstream.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Richard Kleeman
2010-05-27 13:20:15 UTC
Permalink
I have this problem as well in a Lenovo X300 laptop. This has a core 2
duo and an intel graphics driver. I tried powertop under 3 different
system states and got some interesting results.

Regular full boot with X running (desktop):

Number of wakeups per second was around 220 and [kernel scheduler] Load
balancing tick was at about 80 wakeups per second and main culprit.

Full Boot without X running

Number of wakeups per second was around 70 and [kernel scheduler] Load
balancing tick was at about 25 wakeups and the main culprit

Root shell (recovery mode boot)

Number of wakeups per second was around 10 (!!!!) and [kernel scheduler]
Load balancing tick was at about 0.5 wakeups

So it looks like this problem occurs when cpu stress particularly from
video drivers is applied but can occur due to many sources. Sounds like
a bad kernel bug to me.

My laptop runs about 5C warmer with Lucid compared to Karmic so this is
very annoying.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Richard Kleeman
2010-05-31 15:08:51 UTC
Permalink
This is definitely a kernel issue. I ran powertop with the latest Lucid
kernel (2.6.32) and for comparison the last Karmic kernel (2.6.31) and
under the Karmic kernel the number of wakeups from a standard desktop
with no apps open is HALVED (!!!) from 220 down to 100. I am switching
back to the Karmic kernel until they fix this.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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KK
2010-05-31 15:59:34 UTC
Permalink
I have exactly the same experience (going back to the 2.6.31 kernel
makes everything better)... so I agree that it is definitely a kernel
issue.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Richard Kleeman
2010-05-31 16:27:55 UTC
Permalink
Confirmed on two laptops now. Thinkpad X300 and T60. Wakeups drop by
over 50% from this source reverting to Karmic kernel and are running at
least 5C cooler. I notice though that even the old kernel has these
wakeups as an issue which suggests even more room for improvement. I
hope the kernel devs notice this and push the bug upstream.

Judging from the forums and google searches this is affecting a LOT of
people...............
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Orcie
2010-05-31 17:13:52 UTC
Permalink
This bug goes on for quit some time. As Richard Kleeman indicated the
problem is not not only affecting in the kernels from lucid. What is a
realistic time frame that this bug is being solved? I really love
ubuntu/linux but this makes me hestitate reverting to m$....

On Mon, May 31, 2010 at 6:27 PM, Richard Kleeman
Post by Richard Kleeman
Confirmed on two laptops now. Thinkpad X300 and T60. Wakeups drop by
over 50% from this source reverting to Karmic kernel and are running at
least 5C cooler. I notice though that even the old kernel has these
wakeups as an issue which suggests even more room for improvement. I
hope the kernel devs notice this and push the bug upstream.
Judging from the forums and google searches this is affecting a LOT of
people...............
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Confirmed
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load
balancing tick" task, and above 200 when there's any little load, running on
a Core 2 Duo processor (T6500) with a single core enabled (multicore
disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters
and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
USER PID ACCESS COMMAND
/dev/snd/controlC0: etrusco 1606 F.... pulseaudio
etrusco 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
Mixer name : 'Realtek ALC269'
Components : 'HDA:10ec0269,1b0a4009,00100004
HDA:11c11040,1b0a4007,00100200'
Controls : 19
Simple ctrls : 11
Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
Mixer name : 'ATI R6xx HDMI'
Components : 'HDA:1002aa01,00aa0100,00100100'
Controls : 4
Simple ctrls : 1
Simple mixer control 'IEC958',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic
root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1
acpi_osi=linux radeon.blacklist=yes
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Leif Walsh
2010-05-31 17:39:51 UTC
Permalink
Dear all who think this bug is taking too long:

You're right. It's been outstanding for quite some time now, and
really should have been fixed before release, or else the 2.6.32
kernel shouldn't have been accepted.

As it is, the bug is not fixed. The best people for the job are the
linux kernel devs, not ubuntu employees/contributors. They have a
patch and are in the process of reviewing it. Believe me when I tell
you that you want them to finish reviewing it.

Once it's accepted, it'll be pushed in the next 2.6.32 maintenance
release. I expect to see this in .15, if it's not already in .14
(which got pushed a last week and since I haven't been following this
patch, I don't know if it's in there). If it goes in .15, it'll be
another few weeks to couple of months. Once that happens, the ubuntu
people can package it up and release it as a maintenance update.

Depending on the climate, you may also see this patch in a newer,
backported kernel (2.6.33 and above), so if you enable backports you
might see it sooner.

Either way, there's nothing you can do except either wait for a newer
kernel or downgrade to an older kernel (2.6.31 is a good choice, as
evidenced by some people above).

Another way to soften the blow of this bug is simply to give the load
balancer less to do. I've noticed that, while it certainly causes far
more wakeups than it should, the wakeups *scale with the load* of the
computer. Therefore, if you do all the things you normally do to
reduce wakeups, the load balancer will be less of an issue as well.

Whatever you choose to do (I'm just sticking with the kernel and
living with the bug...it's not so bad with my usage pattern), be
patient. You'll get the fix soon enough, and soon after that you'll
forget it was ever a problem.

<wink>If that's not enough for you, go install slackware.</wink>
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Orcie
2010-05-31 17:58:35 UTC
Permalink
Very encouraging Leif. My impatience is more at rest now.

On Mon, May 31, 2010 at 7:39 PM, Leif Walsh <leif.walsh at gmail.com>
Post by Leif Walsh
You're right. It's been outstanding for quite some time now, and
really should have been fixed before release, or else the 2.6.32
kernel shouldn't have been accepted.
As it is, the bug is not fixed. The best people for the job are the
linux kernel devs, not ubuntu employees/contributors. They have a
patch and are in the process of reviewing it. Believe me when I tell
you that you want them to finish reviewing it.
Once it's accepted, it'll be pushed in the next 2.6.32 maintenance
release. I expect to see this in .15, if it's not already in .14
(which got pushed a last week and since I haven't been following this
patch, I don't know if it's in there). If it goes in .15, it'll be
another few weeks to couple of months. Once that happens, the ubuntu
people can package it up and release it as a maintenance update.
Depending on the climate, you may also see this patch in a newer,
backported kernel (2.6.33 and above), so if you enable backports you
might see it sooner.
Either way, there's nothing you can do except either wait for a newer
kernel or downgrade to an older kernel (2.6.31 is a good choice, as
evidenced by some people above).
Another way to soften the blow of this bug is simply to give the load
balancer less to do. I've noticed that, while it certainly causes far
more wakeups than it should, the wakeups *scale with the load* of the
computer. Therefore, if you do all the things you normally do to
reduce wakeups, the load balancer will be less of an issue as well.
Whatever you choose to do (I'm just sticking with the kernel and
living with the bug...it's not so bad with my usage pattern), be
patient. You'll get the fix soon enough, and soon after that you'll
forget it was ever a problem.
<wink>If that's not enough for you, go install slackware.</wink>
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Confirmed
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load
balancing tick" task, and above 200 when there's any little load, running on
a Core 2 Duo processor (T6500) with a single core enabled (multicore
disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters
and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
USER PID ACCESS COMMAND
/dev/snd/controlC0: etrusco 1606 F.... pulseaudio
etrusco 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
Mixer name : 'Realtek ALC269'
Components : 'HDA:10ec0269,1b0a4009,00100004
HDA:11c11040,1b0a4007,00100200'
Controls : 19
Simple ctrls : 11
Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
Mixer name : 'ATI R6xx HDMI'
Components : 'HDA:1002aa01,00aa0100,00100100'
Controls : 4
Simple ctrls : 1
Simple mixer control 'IEC958',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic
root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1
acpi_osi=linux radeon.blacklist=yes
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Brian Rogers
2010-06-01 09:52:16 UTC
Permalink
I put a 2.6.34 kernel with the patches for this issue in this PPA:
https://launchpad.net/~brian-rogers/+archive/power

It's not perfect, but it does reduce load balancer wakeups some. A
mainline build with fully up-to-date scheduler code might do better.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Leif Walsh
2010-06-01 12:01:16 UTC
Permalink
Thanks for your work.

I tested this, and it actually looks to have made things worse, if
anything.

Here are four powertop logs, each run with -d -t 300. Prepatch is the
stock ubuntu kernel as of today, postpatch is your build. Without
load is standard gnome stuff and xmonad running, plus daemons, and
nothing else. With load adds several browser tabs, one of which
downloading playing a long youtube video throughout.

You'll notice that things get worse postpatch in both scenarios, but
probably not to a statistically significant degree.

Perhaps I don't suffer from this bug?

If you get the chance, since you already have the machinery to make
debian builds (and I've never actually figured out the proper way to
do this for the kernel), do you think you could build me a copy of the
same thing, but with the timer frequency set to 100Hz? Feel free to
just mail me debs rather than uploading them to the ppa, if you can do
this for me.


** Attachment added: "powertop-logs.tar.bz2"
http://launchpadlibrarian.net/49496012/powertop-logs.tar.bz2
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Brian Rogers
2010-06-01 23:54:03 UTC
Permalink
Leif, what was your pre-patch kernel? I'd be interested in a comparison with this kernel:
https://launchpad.net/ubuntu/maverick/+source/linux/2.6.34-5.12

It is the same as my PPA kernel except for the patch, so we can look at
the effect of just the patch.

Also, I took a look at Lucid and Maverick's current kernel config and
found that for both, -generic kernels on i386 have CONFIG_HZ=250 and
amd64 has CONFIG_HZ=100. Seems like an odd choice to have two different
values depending on architecture. It could be a mistake... Also, all the
kernels have CONFIG_NO_HZ set.

If we want to test different configs, I can set them up as flavours and
do -100hz and -250hz kernels on my next upload.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Leif Walsh
2010-06-03 21:19:14 UTC
Permalink
Post by Brian Rogers
https://launchpad.net/ubuntu/maverick/+source/linux/2.6.34-5.12
I'll check this tonight if I get a chance, thanks.
Post by Brian Rogers
It is the same as my PPA kernel except for the patch, so we can look at
the effect of just the patch.
Also, I took a look at Lucid and Maverick's current kernel config and
found that for both, -generic kernels on i386 have CONFIG_HZ=250 and
amd64 has CONFIG_HZ=100. Seems like an odd choice to have two different
values depending on architecture. It could be a mistake... Also, all the
kernels have CONFIG_NO_HZ set.
If we want to test different configs, I can set them up as flavours and
do -100hz and -250hz kernels on my next upload.
Yeah, I checked your kernel config and it's 250Hz so I don't think
that's the cause of the extra wakeups, but I'll make sure the stock
kernel is also 250 tonight. I don't think it's 100, and I really hope
it isn't 1000.
--
Cheers,
Leif
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Brian Rogers
2010-06-02 00:01:23 UTC
Permalink
OK, I found the reason for 250 Hz on i386:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/438234
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Shane Kerr
2010-06-02 10:30:57 UTC
Permalink
Brian, the kernel from your PPA does indeed seem to help a little bit. I
was getting an average of something like 140 wakes per second and now
the average is around 100.

My computer still seems to spend a lot of time doing housekeeping... for
example a recent powertop output:

31,2% ( 78,4) [extra timer interrupt]
21,1% ( 53,0) [kernel scheduler] Load balancing tick
18,5% ( 46,4) [iwlagn] <interrupt>
9,3% ( 23,5) firefox-bin
4,0% ( 10,0) [kernel core] r600_audio_update_hdmi (r600_audio_update_hdmi)
4,0% ( 10,0) ubuntuone-syncd
3,7% ( 9,4) [kernel core] hrtimer_start (tick_sched_timer)

70 wakeups doing something I care about (wireless and Firefox) and 160
doing... other stuff.

Anyway thanks for the kernel, at least it's something until a fix gets
backported officially! (Which I hope will happen, this being LTS and
all.)
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Rocko
2010-06-03 23:11:46 UTC
Permalink
fwiw, I built a 64-bit 1000Hz kernel (with CONFIG_NO_HZ also set) and
found I got a lot more load-balancing wakeups compared to the stock
100Hz kernel.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Trevor Walker
2010-06-07 20:22:59 UTC
Permalink
I had this problem too, and I found that checking ~/.xsession-errors
showed that vino-server was restarting very, very often. Killing it cut
my wakeups from the load balancing tick dramatically. I read on the
Ubuntu forums that someone had a similar situation with Metacity, so I
would suggest checking that log.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Arvid Norlander
2010-06-21 19:36:53 UTC
Permalink
So when can we expect a fix for this in the stock lucid kernel (amd64)?
This reduces battery life with more than half compared to jaunty on my
Thinkpad R500 (Core 2 Duo P8400). Didn't stay on karmic for long enough
to check this (only for about 2 days).
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Jeremy Foshee
2010-06-22 14:09:53 UTC
Permalink
** Changed in: linux (Ubuntu)
Status: Confirmed => Triaged

** Tags added: kernel-core kernel-needs-review
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Kristofer
2010-07-05 05:07:01 UTC
Permalink
This bug confirmed on an eeepc 1005HA with intel atom N280.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Virgil Brummond
2010-07-06 10:20:39 UTC
Permalink
Can anyone confirm this bug on Debian??
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Virgil Brummond
2010-07-06 11:12:14 UTC
Permalink
Did some powertop reports on battery with both the lucid kernel and the
mainline 2.6.34 kernel.

NOTE: This file contains both tests, the lucid kernel on top, and the
mainline kernel below.

** Attachment added: "powertop_report"
http://launchpadlibrarian.net/51456401/powertop_report
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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James Ward
2010-07-12 11:56:33 UTC
Permalink
This is happening to me on the latest maverick with 2.6.35-7-generic-
pae.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Andy Whitcroft
2010-07-12 15:50:37 UTC
Permalink
** Tags added: kernel-candidate kernel-reviewed
** Tags removed: kernel-needs-review
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Jeremy Foshee
2010-07-12 16:20:27 UTC
Permalink
** Tags removed: kernel-candidate
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Andy Whitcroft
2010-07-15 09:17:29 UTC
Permalink
** Changed in: linux (Ubuntu)
Importance: Undecided => Low
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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mabawsa
2010-07-15 11:06:25 UTC
Permalink
If this effects the time the user can use the laptop on battery so much surely the importance should be set to critical (I am getting double the life using Windows 7 even with all that powertop can do).
Its difficult to convince users to try linux if you say it will decrease the performance of the machine.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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alx5000
2010-07-15 11:24:11 UTC
Permalink
I wholeheartedly agree with mabawsa. I've downgraded to Karmic for this very
reason. My battery lasts as long as it should, and my laptop very rarely
overheats (it ran hot as hell with Lucid).

2010/7/15 mabawsa <524281 at bugs.launchpad.net>
Post by mabawsa
If this effects the time the user can use the laptop on battery so much
surely the importance should be set to critical (I am getting double the
life using Windows 7 even with all that powertop can do).
Its difficult to convince users to try linux if you say it will decrease
the performance of the machine.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Triaged
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load
balancing tick" task, and above 200 when there's any little load, running on
a Core 2 Duo processor (T6500) with a single core enabled (multicore
disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters
and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
USER PID ACCESS COMMAND
/dev/snd/controlC0: etrusco 1606 F.... pulseaudio
etrusco 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
Mixer name : 'Realtek ALC269'
Components : 'HDA:10ec0269,1b0a4009,00100004
HDA:11c11040,1b0a4007,00100200'
Controls : 19
Simple ctrls : 11
Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
Mixer name : 'ATI R6xx HDMI'
Components : 'HDA:1002aa01,00aa0100,00100100'
Controls : 4
Simple ctrls : 1
Simple mixer control 'IEC958',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic
root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1
acpi_osi=linux radeon.blacklist=yes
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Antonio
2010-07-15 11:52:14 UTC
Permalink
I agree with the last two comments. Battery lasts half of the time it
lasts on windows 7 and the laptop overheats significantly on a large
spectrum of machines.

This should be a critical bug.

BTW, is there an "official" kernel we can test against this bug? If
yes can anyone post a link please?

Thanks,
Antonio
Post by alx5000
I wholeheartedly agree with mabawsa. I've downgraded to Karmic for this very
reason. My battery lasts as long as it should, and my laptop very rarely
overheats (it ran hot as hell with Lucid).
2010/7/15 mabawsa <524281 at bugs.launchpad.net>
Post by mabawsa
If this effects the time the user can use the laptop on battery so much
surely the importance should be set to critical (I am getting double the
life using Windows 7 even with all that powertop can do).
Its difficult to convince users to try linux if you say it will decrease
the performance of the machine.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Triaged
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load
balancing tick" task, and above 200 when there's any little load, running on
a Core 2 Duo processor (T6500) with a single core enabled (multicore
disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters
and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
?**** List of CAPTURE Hardware Devices ****
?card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
? ?Subdevices: 1/1
? ?Subdevice #0: subdevice #0
?USER ? ? ? ?PID ACCESS COMMAND
?/dev/snd/controlC0: ?etrusco ? ?1606 F.... pulseaudio
? ? ? ? ? ? ? ? ? ? ? etrusco ? 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
?Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
? ?Mixer name ? : 'Realtek ALC269'
? ?Components ? : 'HDA:10ec0269,1b0a4009,00100004
HDA:11c11040,1b0a4007,00100200'
? ?Controls ? ? ?: 19
? ?Simple ctrls ?: 11
?Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
? ?Mixer name ? : 'ATI R6xx HDMI'
? ?Components ? : 'HDA:1002aa01,00aa0100,00100100'
? ?Controls ? ? ?: 4
? ?Simple ctrls ?: 1
?Simple mixer control 'IEC958',0
? ?Capabilities: pswitch pswitch-joined penum
? ?Playback channels: Mono
? ?Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic
root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1
acpi_osi=linux radeon.blacklist=yes
?LANG=en_US.UTF-8
?SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
?0: phy0: Wireless LAN
? Soft blocked: no
? Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Triaged
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load balancing tick" task, and above 200 when there's any little load, running on a Core 2 Duo processor (T6500) with a single core enabled (multicore disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
?**** List of CAPTURE Hardware Devices ****
?card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
???Subdevices: 1/1
???Subdevice #0: subdevice #0
?USER ? ? ? ?PID ACCESS COMMAND
?/dev/snd/controlC0: ?etrusco ? ?1606 F.... pulseaudio
??????????????????????etrusco ? 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
?Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
???Mixer name ? : 'Realtek ALC269'
???Components ? : 'HDA:10ec0269,1b0a4009,00100004 HDA:11c11040,1b0a4007,00100200'
???Controls ? ? ?: 19
???Simple ctrls ?: 11
?Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
???Mixer name ? : 'ATI R6xx HDMI'
???Components ? : 'HDA:1002aa01,00aa0100,00100100'
???Controls ? ? ?: 4
???Simple ctrls ?: 1
?Simple mixer control 'IEC958',0
???Capabilities: pswitch pswitch-joined penum
???Playback channels: Mono
???Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1 acpi_osi=linux radeon.blacklist=yes
?LANG=en_US.UTF-8
?SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
?0: phy0: Wireless LAN
??Soft blocked: no
??Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
KK
2010-07-15 12:02:32 UTC
Permalink
I also agree... compared to Karmic, battery life reduces to half

--- On Thu, 7/15/10, Antonio <tritemio at gmail.com> wrote:

From: Antonio <tritemio at gmail.com>
Subject: Re: [Bug 524281] Re: Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
To: karldialal at yahoo.com
Date: Thursday, July 15, 2010, 6:52 AM

I agree with the last two comments. Battery lasts half of the time it
lasts on windows 7 and the laptop overheats significantly on a large
spectrum of machines.

This should be a critical bug.

BTW, is there an "official" kernel we can test against this bug? If
yes can anyone post a link please?

Thanks,
Antonio
Post by alx5000
I wholeheartedly agree with mabawsa. I've downgraded to Karmic for this very
reason. My battery lasts as long as it should, and my laptop very rarely
overheats (it ran hot as hell with Lucid).
2010/7/15 mabawsa <524281 at bugs.launchpad.net>
Post by mabawsa
If this effects the time the user can use the laptop on battery so much
surely the importance should be set to critical (I am getting double the
life using Windows 7 even with all that powertop can do).
Its difficult to convince users to try linux if you say it will decrease
the performance of the machine.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on
Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Triaged
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load
balancing tick" task, and above 200 when there's any little load, running on
a Core 2 Duo processor (T6500) with a single core enabled (multicore
disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters
and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
?**** List of CAPTURE Hardware Devices ****
?card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
? ?Subdevices: 1/1
? ?Subdevice #0: subdevice #0
?USER ? ? ? ?PID ACCESS COMMAND
?/dev/snd/controlC0: ?etrusco ? ?1606 F.... pulseaudio
? ? ? ? ? ? ? ? ? ? ? etrusco ? 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
?Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
? ?Mixer name ? : 'Realtek ALC269'
? ?Components ? : 'HDA:10ec0269,1b0a4009,00100004
HDA:11c11040,1b0a4007,00100200'
? ?Controls ? ? ?: 19
? ?Simple ctrls ?: 11
?Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
? ?Mixer name ? : 'ATI R6xx HDMI'
? ?Components ? : 'HDA:1002aa01,00aa0100,00100100'
? ?Controls ? ? ?: 4
? ?Simple ctrls ?: 1
?Simple mixer control 'IEC958',0
? ?Capabilities: pswitch pswitch-joined penum
? ?Playback channels: Mono
? ?Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic
root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1
acpi_osi=linux radeon.blacklist=yes
?LANG=en_US.UTF-8
?SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
?0: phy0: Wireless LAN
? Soft blocked: no
? Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.
Status in ?linux? package in Ubuntu: Triaged
Status in ?linux-2.6? package in Debian: Incomplete
powertop reports above 70 wakes per second in "[kernel scheduler] Load balancing tick" task, and above 200 when there's any little load, running on a Core 2 Duo processor (T6500) with a single core enabled (multicore disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters and reproduce it with the mainline kernel.
ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
?**** List of CAPTURE Hardware Devices ****
?card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
???Subdevices: 1/1
???Subdevice #0: subdevice #0
?USER ? ? ? ?PID ACCESS COMMAND
?/dev/snd/controlC0: ?etrusco ? ?1606 F.... pulseaudio
??????????????????????etrusco ? 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
?Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
???Mixer name ? : 'Realtek ALC269'
???Components ? : 'HDA:10ec0269,1b0a4009,00100004 HDA:11c11040,1b0a4007,00100200'
???Controls ? ? ?: 19
???Simple ctrls ?: 11
?Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
???Mixer name ? : 'ATI R6xx HDMI'
???Components ? : 'HDA:1002aa01,00aa0100,00100100'
???Controls ? ? ?: 4
???Simple ctrls ?: 1
?Simple mixer control 'IEC958',0
???Capabilities: pswitch pswitch-joined penum
???Playback channels: Mono
???Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1 acpi_osi=linux radeon.blacklist=yes
?LANG=en_US.UTF-8
?SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
?0: phy0: Wireless LAN
??Soft blocked: no
??Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a direct subscriber
of the bug.

Status in ?linux? package in Ubuntu: Triaged
Status in ?linux-2.6? package in Debian: Incomplete

Bug description:
powertop reports above 70 wakes per second in "[kernel scheduler] Load balancing tick" task, and above 200 when there's any little load, running on a Core 2 Duo processor (T6500) with a single core enabled (multicore disabled in BIOS).
Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters and reproduce it with the mainline kernel.

ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
ArecordDevices:
?**** List of CAPTURE Hardware Devices ****
?card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
???Subdevices: 1/1
???Subdevice #0: subdevice #0
AudioDevicesInUse:
?USER? ? ? ? PID ACCESS COMMAND
?/dev/snd/controlC0:? etrusco? ? 1606 F.... pulseaudio
??????????????????????etrusco???15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
?Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
???Mixer name??? : 'Realtek ALC269'
???Components??? : 'HDA:10ec0269,1b0a4009,00100004 HDA:11c11040,1b0a4007,00100200'
???Controls? ? ? : 19
???Simple ctrls? : 11
Card1.Amixer.info:
?Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
???Mixer name??? : 'ATI R6xx HDMI'
???Components??? : 'HDA:1002aa01,00aa0100,00100100'
???Controls? ? ? : 4
???Simple ctrls? : 1
Card1.Amixer.values:
?Simple mixer control 'IEC958',0
???Capabilities: pswitch pswitch-joined penum
???Playback channels: Mono
???Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1 acpi_osi=linux radeon.blacklist=yes
ProcEnviron:
?LANG=en_US.UTF-8
?SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
RfKill:
?0: phy0: Wireless LAN
??Soft blocked: no
??Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1.01:bd06/01/2009:svnPhilco:pnPHN10XXX.:pvr1.01:rvnPEGATRONCORP.:rn:rvrTobefilledbyO.E.M.:cvnPEGATRONCORP.:ct10:cvrToBeFilledByO.E.M.:
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco


To unsubscribe from this bug, go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+subscribe
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
timo skrempel
2010-07-15 12:15:41 UTC
Permalink
I am considering switching to karmic or another distro because of this
bug. It is open for half a year now, right?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
JedMeister
2010-07-15 13:33:00 UTC
Permalink
I would think that in this age of mobile computing - with so many
notebooks and netbooks around that this would be considered a very
serious bug for this large (and growing) user group. I haven't done
enough testing to confirm but I think this bug is also affecting many
other (perhaps all) Lucid systems (I think it may just more apparent on
laptops because of noticable reduced battery life). Some adhoc testing
has shown that a very basic 10.04 server install (running on KVM) is
chewing noticeably more cpu cycles Also I think the ever growing focus
on more efficient power and concerns for reducing environmental
footprint would also be factors

As a workaround I have found using the Karmic kernel restores battery
life (and reduces overheating). Whilst it works, its hardly an ideal
situation and not really useful for newb users. This sort of serious
regression, especially when left unaddressed, is a really unfortunate
blight for such a promising notable and user friendly distro. Even
moreso when this is a LTS. I was hoping to run 10.04 on a number of work
netbooks that I administer. Unfortunately it looks like that may not be
a realistic option.

Is there anything ppl like myself can do to assist getting this bug
fixed asap?
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
JedMeister
2010-07-15 13:35:31 UTC
Permalink
Sorry, please disregard the comment re this bug affecting a server
system - I don't think that is related.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Richard Kleeman
2010-07-15 13:53:39 UTC
Permalink
I would also agree that this really needs fixing. I have tried a large
range of kernels now ranging from 2.6.31 through to 2.6.35 (maverick
kernel) and compared wakeups using powertop. The only sensitivity in
this list is that the earliest kernel (Karmic kernel 2.6.31) shows half
the wakeups of all the other kernels. Such a result is consistent with
the many reports above of a halving of battery life between Karmic and
Lucid.

I also note that this issue was raised on the kernel mailing list in
April and May and a patch was suggested but there was no follow up. Note
that this is also a Debian bug as well. My strong suspicion is that this
is a basic problem with the kernel and switching to another distro would
not help. If this is not the case I would welcome evidence that another
distro with a kernel in the range 2.6.32-2.6.35 DOES NOT have this
issue.

If it is an upstream kernel problem I think that someone needs to lodge
a critical bug on the kernel bugzilla.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Richard Kleeman
2010-07-15 14:05:09 UTC
Permalink
Some further searching turned up this relevant thread on the kernel
mailing list:

http://www.listware.net/201007/linux-kernel/16253-high-power-
consumption-in-recent-kernels.html

A patch is tested there which resulted in a very big reduction in
wakeups and power consumption. There is a lot of technical discussion in
that thread which I did not understand but seems important. Comments by
a Ubuntu kernel expert would be very welcome.....
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Richard Kleeman
2010-07-15 14:19:50 UTC
Permalink
Here is the relevant thread on lkml:

http://lkml.org/lkml/2010/7/6/172

Notice that is is very recent (<10 days ago) and that Arjan van de Ven the author
of powertop and a lead kernel developer working for intel is involved in the thread.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Brian Rogers
2010-07-15 14:57:42 UTC
Permalink
For anyone who wants to test a kernel with the scheduling changes that will be merged in 2.6.36, I've uploaded a kernel to this PPA:
https://launchpad.net/~brian-rogers/+archive/power

This is Maverick's v2.6.35-rc5 kernel with the sched/core branch from
the tip tree merged in.

The build system is backlogged right now, so it might be about 24 hours
before the builds are actually available.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Jan-Philipp Litza
2010-07-15 15:24:15 UTC
Permalink
Well, I was about to rant half an hour ago about people complaining here
without understanding the issue, but Richard clearly explained the issue
- thanks for that.

As for other ditros, I just booted my Arch Linux I had installed some
time ago to test this. The older powertop version 1.11 shows the wakeups
as coming from "hrtimer_start_range_ns (tick_sched_timer)" instead of
"[kernel scheduler] Load balancing tick", but has exactly the same
numbers as the newer powertop 1.12. Arch was running 2.6.34-ARCH, my
Ubuntu is running 2.6.32-24 as well as 2.6.34.1, and the figures are
identical, so NO, switching the distro doesn't help!

I'll rework the description in a moment to better describe the cause of
the problem, list possible workarounds (namely downgrading to 2.6.31 or
upgrading to -tip/Brian's ppa) and linking in the lkml threads.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Jan-Philipp Litza
2010-07-15 15:37:26 UTC
Permalink
** Description changed:

- powertop reports above 70 wakes per second in "[kernel scheduler] Load balancing tick" task, and above 200 when there's any little load, running on a Core 2 Duo processor (T6500) with a single core enabled (multicore disabled in BIOS).
- Will still try noapic, nolapic, maxcpus and nosmp in the boot parameters and reproduce it with the mainline kernel.
+ powertop reports many wakes per second (quantity depending on system)
+ in "[kernel scheduler] Load balancing tick" task, rising with little
+ load, on many kinds of multi-core (?) systems (original report was on a
+ Core 2 Duo processor (T6500) with a single core enabled (multicore
+ disabled in BIOS)).
+
+ Cause of the problem:
+ With kernel 2.6.32, there came a patch to the scheduler that introduced this problem (that was backported to some other versions as well). Even though this problem occurred first in Lucid, it is NOT specific to Lucid or Ubuntu at all (Debian bug report at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521944, reproducable in Arch Linux as well). Work is ongoing to get things straight in kernel, but it will take a long time until this reaches Ubuntu (see http://lkml.org/lkml/2010/7/6/172).
+
+ Workarounds that DO NOT work (may improve situation but not solve it):
+ - maxcpus=1
+ - noapic
+ - nosmp
+ - nolapic
+ - use mainline kernel
+
+ Workarounds that DO (probably) work:
+ - tip version of kernel (git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git, from http://lkml.org/lkml/2010/7/8/75)
+ - use maverick's kernel with applied patches (https://launchpad.net/~brian-rogers/+archive/power, from comment #80)

ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
ArecordDevices:
?**** List of CAPTURE Hardware Devices ****
?card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
???Subdevices: 1/1
???Subdevice #0: subdevice #0
AudioDevicesInUse:
?USER PID ACCESS COMMAND
?/dev/snd/controlC0: etrusco 1606 F.... pulseaudio
??????????????????????etrusco 15151 F.... foobar2000.exe
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
?Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
???Mixer name : 'Realtek ALC269'
???Components : 'HDA:10ec0269,1b0a4009,00100004 HDA:11c11040,1b0a4007,00100200'
???Controls : 19
???Simple ctrls : 11
Card1.Amixer.info:
?Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
???Mixer name : 'ATI R6xx HDMI'
???Components : 'HDA:1002aa01,00aa0100,00100100'
???Controls : 4
???Simple ctrls : 1
Card1.Amixer.values:
?Simple mixer control 'IEC958',0
???Capabilities: pswitch pswitch-joined penum
???Playback channels: Mono
???Mono: Playback [on]
Date: Fri Feb 19 05:25:42 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
MachineType: Philco PHN10XXX.
Package: linux-image-2.6.32-13-generic 2.6.32-13.18
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1 acpi_osi=linux radeon.blacklist=yes
ProcEnviron:
?LANG=en_US.UTF-8
?SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.29
Reproducible: Yes
RfKill:
?0: phy0: Wireless LAN
??Soft blocked: no
??Hard blocked: no
SourcePackage: linux
TestedUpstream: No
Uname: Linux 2.6.32-13-generic i686
dmi.bios.date: 06/01/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1.01:bd06/01/2009:svnPhilco:pnPHN10XXX.:pvr1.01:rvnPEGATRONCORP.:rn:rvrTobefilledbyO.E.M.:cvnPEGATRONCORP.:ct10:cvrToBeFilledByO.E.M.:
dmi.product.name: PHN10XXX.
dmi.product.version: 1.01
dmi.sys.vendor: Philco
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Richard Kleeman
2010-07-16 13:43:28 UTC
Permalink
I tested Brian Roger's 2.6.35-rc5 kernel with the scheduling changes and
saw little difference on a Intel(R) Core(TM)2 Duo CPU (Thinkpad X300).
Here is the powertop output with a firefox browser open:


Wakeups-from-idle per second : 308.9 interval: 15.0s
no ACPI power usage estimate available
Top causes for wakeups:
30.6% ( 79.3) [kernel scheduler] Load balancing tick
19.2% ( 49.9) [extra timer interrupt]
16.5% ( 42.9) [kernel core] hrtimer_start (tick_sched_timer)
0.1% ( 0.3)D upowerd
5.9% ( 15.2) [iwlagn] <interrupt>
0.3% ( 0.8)D gnome-settings-
4.6% ( 11.9) firefox-bin
4.2% ( 11.0) nautilus
3.9% ( 10.0) syndaemon
3.1% ( 8.1) [kernel core] usb_hcd_poll_rh_status (rh_timer_func)
2.2% ( 5.7) [ahci] <interrupt>
1.6% ( 4.3) [TLB shootdowns] <kernel IPI>
0.0% ( 0.0)D flush-8:0
1.2% ( 3.1) Xorg

Compared with the standard Lucid kernel, the Load balancing tick wakeups
are down about 10% while the hrtimer_start (tick_sched_timer) are up
some.

These results compare with using the Karmic kernel where wakeups were
halved.

Brian: Did you apply the patch noted in the lkml thread I posted above?
The claim there is a substantial wakeups reduction with that applied.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
You received this bug notification because you are a member of Kernel
Bugs, which is subscribed to linux in ubuntu.
Brian Rogers
2010-07-16 15:53:10 UTC
Permalink
I didn't include that before, so now I'm uploading a new kernel
(2.6.35rc5-power2.1) with the patch from
http://lkml.org/lkml/2010/7/8/122
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Stefano Maggiolo
2010-07-16 19:25:56 UTC
Permalink
On my netbook (single cpu Atom N450) the -power1 improves considerably
the situation: idling there is a trascurable amount of wake ups again
(very good) while working the situation is somehow better but there are
still a lot of balancing tick (a bit better).

If I understand correctly, on a single core system they should be
totally absent, isn't it?

(BTW: I'd really like if solving this bug would double battery life, but
sadly this is quite pessimistic, or optimistic depending on the point of
view)

Thanks for the backporting/patching! I'm going to try the new one.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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mabawsa
2010-07-17 03:14:07 UTC
Permalink
I already have a patched kernel on y system for another issue. Could
anybody point me to the right patches to test?
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Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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skhawam
2010-07-17 10:07:09 UTC
Permalink
Hi Brian,

I tried the 2.6.35rc5-power2 kernel and it's definitely better than even
the Karmic 2.6.31-20 I was using. With no load it reduces the wakes and
power (I get 6ms C4 state as opposed to 3ms). However, with simple load
on (chrome, thunderbird, emapthy and ssh client running) I get around
~300 wakes per second and 3ms C4 state. The power consumption is much
better but I think there is still room for improvements. This is the
best kernel till now.

I have a Dell Mini 10v, with Atom N270 processor.

Sami
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Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Richard Kleeman
2010-07-17 13:12:11 UTC
Permalink
OK I tried the power2 kernel and there is a definite improvement. Here
are the latest powertop numbers:

Wakeups-from-idle per second : 207.9 interval: 15.0s
no ACPI power usage estimate available
Top causes for wakeups:
27.3% ( 33.8) [kernel scheduler] Load balancing tick
0.7% ( 0.9)D gnome-settings-
12.3% ( 15.3) [extra timer interrupt]
9.8% ( 12.1) [iwlagn] <interrupt>
9.8% ( 12.1) firefox-bin
8.9% ( 11.0) nautilus
8.1% ( 10.0) syndaemon
3.4% ( 4.2) [TLB shootdowns] <kernel IPI>
2.5% ( 3.1) Xorg
2.4% ( 3.0) [kernel core] hrtimer_start (tick_sched_timer)

You can see substantial reductions in the wakeups from all three kernel sources as well as the total number of wakeups. The reductions are pretty much consistent with the numbers reported in the kernel thread.
Also subjectively the laptop does appear to be running a bit cooler (maybe 4C).

Just for clarification Brian, you patched with the second patch in the
thread right? (two were mentioned and the second was better).

Looks like there is still room for improvement but at least this is
progress. Pretty simple patch too by the look of it.
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Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Brian Rogers
2010-07-17 19:20:45 UTC
Permalink
Yeah, I used the second patch. I applied it on top of the tip/sched/core
branch. I'll attach it for convenience.

** Patch added: "Patch from mailing list"
http://launchpadlibrarian.net/52089149/0001-Apply-patch-from-http-lkml.org-lkml-2010-7-8-122.patch
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Pawel
2010-07-17 22:49:27 UTC
Permalink
I've got such results in Arch Linux:

Top causes for wakeups:
25,0% ( 25,1) <kernel IPI> : Rescheduling interrupts
19,0% ( 19,1) <kernel core> : hrtimer_start_range_ns (tick_sched_timer)
11,3% ( 11,3) firefox : hrtimer_start_range_ns (hrtimer_wakeup)
11,2% ( 11,2) <interrupt> : ath
10,2% ( 10,3) <kernel core> : hrtimer_start (tick_sched_timer)
9,9% ( 9,9) radeon/1 : queue_delayed_work (delayed_work_timer_fn)
8,1% ( 8,1) <interrupt> : ahci
1,0% ( 1,0) powernowd : hrtimer_start_range_ns (hrtimer_wakeup)
0,5% ( 0,5) <interrupt> : ohci_hcd:usb4, ohci_hcd:usb6, radeon
0,5% ( 0,5) kwin : hrtimer_start_range_ns (hrtimer_wakeup)

2.6.34-ARCH #1 SMP PREEMPT Mon Jul 5 22:12:11 CEST 2010 x86_64 AMD
Athlon(tm) 64 X2 Dual Core Processor 5000+ AuthenticAMD GNU/Linux
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Brian Murray
2010-07-17 23:03:35 UTC
Permalink
** Tags added: patch
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Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Jorge O. Castro
2010-07-19 10:05:32 UTC
Permalink
Brian Rogers,

Thanks for the PPA, it's made this easier to test. My wake ups are down
from ~250 to about ~45. I asked Jeremy Foshee from the kernel team on
how best to continue testing this:

- We should probably see how the LKML discussion evolves and see if there's a final fix. When the patch is accepted upstream we can put it in Maverick.
- At some point after testing since this is affecting Lucid users we can cherrypick it into an update.
- We can use this bug to give feedback on the patch, so if it's improved your situation (or worsened it) then we can help collectively test.
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Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Caleb Case
2010-07-19 14:51:41 UTC
Permalink
Before: ~80 [kernel scheduler] Load balancing tick
After: ~20

2.6.35rc5-power2-generic #1-Ubuntu SMP Sat Jul 17 08:39:54 UTC 2010 x86_64 GNU/Linux
Intel(R) Core(TM) i5 CPU M 450

Much improved, thanks!
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
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Richard Kleeman
2010-07-19 15:19:49 UTC
Permalink
Jorge and Brian,

Thanks for your input and ppa. Much appreciated. My reading of the
kernel LKML discussion is that something rather serious was screwed up
in the implementation of the nohz part of the kernel scheduler and that
the patch was a first test of this idea. The results there and in this
bug thread seem to confirm that suspicion but I would be more
comfortable if the two kernel developers in that thread (Peter Zijlstra
and Arjan Van de Ven) had further responded on the issue. Perhaps a
Ubuntu kernel developer should engage with these devs on LKML to clear
this issue up...
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Brian Rogers
2010-07-19 19:18:30 UTC
Permalink
It looks like nohz_ratelimit will be reverted for 2.6.35, which is
essentially the change included in the power2 kernel. But the power2
kernel also includes changes scheduled for 2.6.36. So to ensure that the
revert alone is enough to solve the problem, I'm uploading a power3
kernel with only the revert.

If the power3 kernel is fine, then this will be solved in the final
2.6.35 kernel and therefore Maverick.

Now the bad news: this fix can't be backported to Lucid's 2.6.32 because
it's simply the removal of something added after 2.6.32. In other words,
Lucid suffers from this problem for a different reason. On the bright
side, it's apparently something that was fixed later, so it should be
possible to look at post-2.6.32 scheduler changes and find a fix.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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Leif Walsh
2010-07-19 19:29:40 UTC
Permalink
I installed power2 and noticed some issues where, under small load (playing
a video), the mouse cursor would move very slowly. Has anyone else seen
this? I can try to reproduce later this week.

On Jul 19, 2010 12:26 PM, "Brian Rogers" <brian at xyzw.org> wrote:

It looks like nohz_ratelimit will be reverted for 2.6.35, which is
essentially the change included in the power2 kernel. But the power2
kernel also includes changes scheduled for 2.6.36. So to ensure that the
revert alone is enough to solve the problem, I'm uploading a power3
kernel with only the revert.

If the power3 kernel is fine, then this will be solved in the final
2.6.35 kernel and therefore Maverick.

Now the bad news: this fix can't be backported to Lucid's 2.6.32 because
it's simply the removal of something added after 2.6.32. In other words,
Lucid suffers from this problem for a different reason. On the bright
side, it's apparently something that was fixed later, so it should be
possible to look at post-2.6.32 scheduler changes and find a fix.
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core
2 Duo even with on...
--
Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
https://bugs.launchpad.net/bugs/524281
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