Messages in this thread | | | Subject | Re: hackbench regression with kernel 2.6.32-rc1 | From | Mike Galbraith <> | Date | Wed, 28 Oct 2009 15:22:59 +0100 |
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On Wed, 2009-10-28 at 17:29 +0800, Zhang, Yanmin wrote: > -Mike > I'm investigating 5% tbench regression on Nehalem machine. perf_counter shows > select_task_rq_fair consumes about 5% cpu time with 2.6.32-rc1 while it consumes > less than 0.5% with 2.6.31. > > Patch c88d5910890 has comments to explain it, but I still can't understand why > to add complicated balance logic when selecting task rq. > > I will check which section in function select_task_rq_fair consumes so much time.
Turn off SD_WAKE_BALANCE as it was called in rc1. See commit 182a85f.
-Mike
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