lkml.org 
[lkml]   [2007]   [Oct]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: aim7 -30% regression in 2.6.24-rc1
From
Date
On Mon, 2007-10-29 at 17:37 +0800, Zhang, Yanmin wrote:
> On Mon, 2007-10-29 at 10:22 +0800, Zhang, Yanmin wrote:
> > On Fri, 2007-10-26 at 13:23 +0200, Ingo Molnar wrote:
> > > * Zhang, Yanmin <yanmin_zhang@linux.intel.com> wrote:
> > >
> > > > I tested 2.6.24-rc1 on my x86_64 machine which has 2 quad-core processors.
> > > >
> > > > Comparing with 2.6.23, aim7 has about -30% regression. I did a bisect
> > > > and found patch
> > > > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=b5869ce7f68b233ceb81465a7644be0d9a5f3dbb
> > > > caused the issue.
> > >
> > > weird, that's a commit diff - i.e. it changes no code.
> > I got the tag from #git log. As for above link, I just added prior http address,
> > so readers could check the patch by clicking.
> >
> > >
> > > > kbuild/SPECjbb2000/SPECjbb2005 also has big regressions. On my another
> > > > tigerton machine (4 quad-core processors), SPECjbb2005 has more than
> > > > -40% regression. I didn't do a bisect on such benchmark testing, but I
> > > > suspect the root cause is like aim7's.
> > >
> > > these two commits might be relevant:
> > >
> > > 7a6c6bcee029a978f866511d6e41dbc7301fde4c
> > I did a quick testing. This patch has no impact.
> >
> > > 95dbb421d12fdd9796ed153853daf3679809274f
> > Above big patch doesn't include this one, which means if I do
> > 'git checkout b5869ce7f68b233ceb81465a7644be0d9a5f3dbb', the kernel doesn't include
> > 95dbb421d12fdd9796ed153853daf3679809274f.
> >
> > >
> > > but a bisection result would be the best info.
> > I will do a bisect between 2.6.23 and tag 9c63d9c021f375a2708ad79043d6f4dd1291a085.
> I ran git bisect with kernel version as the tag. It looks like git will
> be crazy sometimes. So I checked ChangeLog and used the number tag to replace
> the kernel version and retested it.
>
> It looks like at least 2 patches were responsible for the regression. I'm
> doing sub-bisect now.
>
> I could find aim7 regression on all my testing machines although the regression
> percentage is different.
>
> Machine regression
> 8-core stoakley 30%
> 16-core tigerton 6%
> tulsa(dual-core+HT, 16 logical cpu) 20%
sub-bisecting captured patch 38ad464d410dadceda1563f36bdb0be7fe4c8938(sched: uniform tunings)
caused 20% regression of aim7.

The last 10% should be also related to sched parameters, such like
sysctl_sched_min_granularity.

-yanmin
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-10-30 03:17    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site