From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12 Description of problem: When running powertop in the latest kernel, powertop reports a lot of wakeups due to "Rescheduling interrupts". This type of wakeup was not seen in the previous 2.6.23 kernels. I've also noticed that the battery life of my laptop has degraded ever since upgrading to this kernel. Version-Release number of selected component (if applicable): kernel-2.6.24.3-34 How reproducible: Sometimes Steps to Reproduce: 1. Run powertop 2. Look at the "Top causes for wakeups" section 3. Actual Results: Rescheduling interrupts is sometimes listed as the 1st or 2nd top cause, even under minimal loads. I have listed in the attachments powertop when there has been high load (powertop.png) and just normal idle-like load (powertop4.png) Expected Results: Additional info: I've also tried downloading the vanilla 2.6.24 kernel from kernel.org. Same problem is being exhibited.
Created attachment 299120 [details] Powertop screenshot during high load Notice the large amount of 'rescheduling interrupts' that are occurring.
Created attachment 299122 [details] Powertop screenshot during idle load Notice that rescheduling interrupts is waking up the processor almost as much as the worst offender (nvidia driver). Note that this did not occur in the previous 2.6.23-based kernels.
I forgot to mention that I am running Fedora 8 on an Intel Core 2 Duo 2.16 GHz so it is utilising both cores. I say this because I just found another bug report (related to the 2.6.24 kernel) that reports turning off one core "solves" this problem. http://www.mail-archive.com/ubuntu-bugs@lists.ubuntu.com/msg703359.html
This happens under x86_64 with 2.6.24.3-50.fc8 as well.
I've an Intel Core 2 Duo T8100 (2.1 GHz, 3MiB cache) which sees a large number of rescheduling interrupts as well: From running cat /proc/interrupts && uptime, RES: 484716 473786 Rescheduling interrupts 19:43:53 up 1:17, 2 users, load average: 1.18, 1.21, 1.13 so that's around 200/s. This is on kernel-2.6.24.7-92.fc8, booted nohz=off. Could this be the reason why tasks seem to keep hopping between the cores on my system rather than staying on one?
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Still present in Fedora 10.
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Fedora 10 changed to end-of-life (EOL) status on 2009-12-17. Fedora 10 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. Thank you for reporting this bug and we are sorry it could not be fixed.
In F-12 I can see around 36 wakeups per second when the system is idle.
This message is a reminder that Fedora 12 is nearing its end of life. Approximately 30 (thirty) days from now Fedora will stop maintaining and issuing updates for Fedora 12. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as WONTFIX if it remains open with a Fedora 'version' of '12'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version prior to Fedora 12's end of life. Bug Reporter: Thank you for reporting this issue and we are sorry that we may not be able to fix it before Fedora 12 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora please change the 'version' of this bug to the applicable version. If you are unable to change the version, please add a comment here and someone will do it for you. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete. The process we are following is described here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
Fedora 12 changed to end-of-life (EOL) status on 2010-12-02. Fedora 12 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. Thank you for reporting this bug and we are sorry it could not be fixed.