Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Arch Linux |
New
|
Undecided
|
Unassigned | ||
linux (Ubuntu) |
Fix Released
|
Low
|
Unassigned | ||
linux-2.6 (Debian) |
Fix Released
|
Unknown
|
|||
xorg (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
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://
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://
- use maverick's kernel with applied patches (https:/
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/
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,
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,
Controls : 4
Simple ctrls : 1
Card1.Amixer.
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-
ProcCmdLine: BOOT_IMAGE=
ProcEnviron:
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSign
Regression: No
RelatedPackageV
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.
dmi.board.vendor: PEGATRON CORP.
dmi.board.version: To be filled by O.E.M.
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: PEGATRON CORP.
dmi.chassis.
dmi.modalias: dmi:bvnAmerican
dmi.product.name: PHN10XXX.
dmi.product.
dmi.sys.vendor: Philco
description: | updated |
Changed in linux-2.6 (Debian): | |
status: | Unknown → Incomplete |
Changed in linux (Ubuntu): | |
status: | Confirmed → Triaged |
tags: | added: kernel-core kernel-needs-review |
tags: |
added: kernel-candidate kernel-reviewed removed: kernel-needs-review |
tags: | removed: kernel-candidate |
Changed in linux (Ubuntu): | |
importance: | Undecided → Low |
description: | updated |
tags: | added: patch |
Changed in linux (Ubuntu): | |
status: | Triaged → Confirmed |
Changed in xorg (Ubuntu): | |
status: | New → Invalid |
Changed in linux (Ubuntu): | |
assignee: | nobody → Matúš Behun (matus-behun) |
Changed in linux (Ubuntu): | |
assignee: | Matúš Behun (matus-behun) → nobody |
Changed in linux-2.6 (Debian): | |
status: | Incomplete → Fix Released |
Confirmed on a ThinkPad X61. This is new in Lucid Alpha 3, wasn't there in Alpha 2.