|Summary:||2.6.25-rc1: volanoMark regression|
|Product:||Process Management||Reporter:||Rafael J. Wysocki (rjw)|
|Component:||Scheduler||Assignee:||Ingo Molnar (mingo)|
|Severity:||normal||CC:||bsingharora, bunk, dhaval, mingo|
|Bug Depends on:|
Description Rafael J. Wysocki 2008-02-13 16:08:36 UTC
Subject : 2.6.25-rc1: volanoMark 45% regression Submitter : "Zhang, Yanmin" <email@example.com> Date : 2008-02-13 10:30 References : http://lkml.org/lkml/2008/2/13/128 Handled-By : Srivatsa Vaddagiri <firstname.lastname@example.org> This entry is being used for tracking a regression from 2.6.24. Please don't close it until the problem is fixed in the mainline.
Comment 1 Rafael J. Wysocki 2008-02-13 16:09:02 UTC
Caused by: commit 58e2d4ca581167c2a079f4ee02be2f0bc52e8729 Author: Srivatsa Vaddagiri <email@example.com> Date: Fri Jan 25 21:08:00 2008 +0100 sched: group scheduling, change how cpu load is calculated
Comment 2 Rafael J. Wysocki 2008-02-24 16:05:02 UTC
Handled-By : Balbir Singh <firstname.lastname@example.org>
Comment 3 Rafael J. Wysocki 2008-03-12 15:43:13 UTC
References : http://lkml.org/lkml/2008/3/12/52 Yanmin said: Peter reverted the load balance patch and 2.6.25-rc4 accepted the reverting patch. With kernel 2.6.25-rc5, volanoMark has about 6% regression on my 16-core tigerton. If I apply patch http://lkml.org/lkml/2008/2/20/83 which fixes the tbench regression issue, volanoMark regression becomes about 4%. I tried to bisect down which patch caused the last 4%, but found it's very hard. One thing is many patches depend on the reverted patches. The other thing is I find the testing result isn't stable since 2.6.25-rc1. The result variation might be more than 15% sometimes. I ran the testing against the same kernel for many times to get the best result. I also tried to tune some sched_XXX parameters under /proc/sys/kernel, but didn't get better result than the default configuration. Above regression exists on the 2.93GHz 16-core tigerton. With the less powerful 2.40GHz 16-core tigerton, the regression is less than 1%, but result is not stable and results of many runs might have about 15% variation. On 8-core stoakley, the regression is about 1%.
Comment 4 Rafael J. Wysocki 2008-03-18 17:40:21 UTC
References : http://lkml.org/lkml/2008/3/18/81 Caused by: commit e22ecef1d2658ba54ed7d3fdb5d60829fb434c23 Author: Ingo Molnar <email@example.com> Date: Fri Mar 14 22:16:08 2008 +0100 sched: fix fair sleepers
Comment 5 Rafael J. Wysocki 2008-04-06 13:50:00 UTC