From: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: dbench 15% regression with 2.6.28-rc1
Date: Tue, 28 Oct 2008 16:41:30 +0800 [thread overview]
Message-ID: <1225183290.1685.73.camel@ymzhang> (raw)
Comparing with 2.6.27, dbench result has regression with 2.6.28-rc1 on 2 machines.
1) 8-core stoakley: 15%
2) 8 core+mutl-thread new-model x86-64: 12%
Bisect located below patch.
695698500912c4479ddf4723e492de3970ff8530 is first bad commit
commit 695698500912c4479ddf4723e492de3970ff8530
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Tue Sep 23 14:54:23 2008 +0200
sched: rework wakeup preemption
Rework the wakeup preemption to work on real runtime instead of
the virtual runtime. This greatly simplifies the code.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I reverted the patch against 2.6.28-rc2 and the regression mostly disappears
on 8-core stoakley and 8-core+multiThread x86-64 machines.
On other 2 machines, I see improvement instead of regression.
1) 16-core tigerton: improvement 48%
2) 8-core+hyperThreading tulsa: 10%.
I just checked it by reverting above patch to see if the patch improves it. At least
it isn't on tigerton. I'm doing a new bisect on tigerton to see what patch improves
dbench result.
I start online cpu number of dbench processes.
-yanmin
next reply other threads:[~2008-10-28 8:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-28 8:41 Zhang, Yanmin [this message]
2008-10-31 9:14 ` dbench 15% regression with 2.6.28-rc1 Zhang, Yanmin
2008-10-31 9:23 ` Peter Zijlstra
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