high load continuously while idling

Bug #991370 reported by mp on 2012-04-29
This bug affects 2 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)

Bug Description

After installing 12.04 64 bit the average load is continuously high (above 1) while idling and the temperature is about 5-10 degrees higher than in 11.04. If performing a few tasks the machine jitters and, for instance, music plays with interruptions.

Tried Lubuntu, also 64 bit, and there is no such problem. There was no such problem in 11.04, so I filed this against Unity.

The system is basically useless.

The machine is a Thinkpad Edge Core i-3

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.12-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CrashDB: unity
Date: Sun Apr 29 20:28:32 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120423)
 PATH=(custom, no user)
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)

mp (m-p) wrote :
mp (m-p) wrote :

Enabled "proposed" repo and updated, which has brought the load wee bit down, as well as the temperature, to the point where the fan is not running all the time, but only every 3 minutes

Firat Birlik (fbirlik) wrote :

This problem is introduced in the kernel and I can confirm that following commit is responsible: "sched: Fix nohz load accounting"
SHA: 3a50863f6706ece7719a68be0ae57957164a0f0c

It is introduced between following tags:
* Ubuntu-3.2.0-21.34
* Ubuntu-3.2.0-22.35

All tags after Ubuntu-3.2.0-22.35 are affected and reverting this commit fixes the high load behaviour. I built following tags with this commit reverted and verified the high load behaviour goes away:
* Ubuntu-3.2.0-22.35
* Ubuntu-3.2.0-23.36
* Ubuntu-3.2.0-24.38 (currently latest tag)

I couldn't reproduce/observe shortened battery life, but if anybody is interested I can provide binary/source deb's with this commit reverted for quick testing. (ppa can't hold full kernel package build)

mp (m-p) wrote :

FYI: In 12.04 32-bit high load is also present, but it significant less than on 64 bit.

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in ubuntu:
status: New → Confirmed
Omer Akram (om26er) on 2012-06-20
affects: unity → ubuntu
shankao (shankao) wrote :

Package set to "linux" after the comments above

affects: ubuntu → linux (Ubuntu)
Changed in linux (Ubuntu):
status: New → Confirmed

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 991370

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: New → Incomplete
Launchpad Janitor (janitor) wrote :

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

Changed in linux (Ubuntu):
status: Incomplete → Expired
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