Re: 2.6.25-rc4-git3: Reported regressions from 2.6.24

[Rafael J. Wysocki]

On Wednesday, 12 of March 2008, Zhang, Yanmin wrote:
> On Mon, 2008-03-10 at 01:32 +0100, Rafael J. Wysocki wrote:
> > [Due to the lack of time for reviewing all of the email threads related to the
> > regressions marked as "unresolved" below, I might have missed some patches
> > fixing them.  If you are involved in debugging/fixing any of them, please let
> > me know if I should update the list.  Thanks!]
> > 
> > This message contains a list of some regressions from 2.6.24 reported since
> > 2.6.25-rc1 was released, for which there are no fixes in the mainline I know
> > of.  If any of them have been fixed already, please let me know.
> > 
> > If you know of any other unresolved regressions from 2.6.24, please let me know
> > either and I'll add them to the list.  Also, please let me know if any of the
> > entries below are invalid.
> > 
> > 
> > Listed regressions statistics:
> > 
> >   Date          Total  Pending  Unresolved
> >   ----------------------------------------
> >   2008-03-10      138       66          47
> >   2008-03-03      115       65          49
> >   2008-02-25       90       51          39
> >   2008-02-17       61       45          37
> > 
> > 
> > Unresolved regressions
> > ----------------------
> > Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=9978
> > Subject		: 2.6.25-rc1: volanoMark 45% regression
> > Submitter	: Zhang, Yanmin <yanmin_zhang@xxxxxxxxxxxxxxx>
> > Date		: 2008-02-13 10:30
> > References	: http://lkml.org/lkml/2008/2/13/128
> > Handled-By	: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>
> > 		  Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> 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%.
> 
> Sorry for the late update.

No problem.

Thanks for the update, I added the new information to the Bugzilla entry.

However, since the regression is still there, I don't think we can close it.

Thanks,
Rafael
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