Re: hackbench regression with 2.6.26-rc2 on tulsa machine

From: Mike Galbraith
Date: Wed May 21 2008 - 01:20:13 EST



On Wed, 2008-05-21 at 12:54 +0800, Zhang, Yanmin wrote:
> On Tue, 2008-05-20 at 11:22 +0200, Mike Galbraith wrote:

> > Do you still have group scheduling enabled?
> Yes.
> CONFIG_GROUP_SCHED=y
> CONFIG_FAIR_GROUP_SCHED=y
> # CONFIG_RT_GROUP_SCHED is not set
> CONFIG_USER_SCHED=y
> # CONFIG_CGROUP_SCHED is not set
>
> > If so, can you turn it off
> > and try again? (when in doubt, grasp at any straw within reach;)
> I reran the test for dozeons of times.
> 1) Background processes have impact on the result and cause result to fluctuate with 8~9 seconds;
> 2) After turning off most services (background processes), the result looks stable;
> 3) I tested both 2.6.26-rc1 and 2.6.26-rc2 with ïCONFIG_GROUP_SCHED=n. the first one's result
> is about 30 seconds and the second one's result is about 31 seconds. So ïCONFIG_GROUP_SCHED is the key.

Thanks a bunch for re-testing.

-Mike

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