** Changed in: linux (Ubuntu)
Assignee: Matúš Behun (matus-behun) => (unassigned)
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https://bugs.launchpad.net/bugs/524281
Title:
Tens of wakes per second in "[kernel scheduler] Load balancing tick"
on Core 2 Duo even with only 1 core enabled
Status in “linux” package in Ubuntu:
Fix Released
Status in “xorg” package in Ubuntu:
Invalid
Status in Arch Linux:
New
Status in “linux-2.6” package in Debian:
Incomplete
Bug description:
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
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