Messages in this thread | | | Subject | dbench 15% regression with 2.6.28-rc1 | From | "Zhang, Yanmin" <> | Date | Tue, 28 Oct 2008 16:41:30 +0800 |
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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
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