Messages in this thread | | | Date | Mon, 27 Jan 2014 20:23:58 +0800 | From | Fengguang Wu <> | Subject | Re: [percpu_counter] 74e72f894: -47.6% aim7 jobs-per-min |
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Hi Ming Lei,
On Fri, Jan 17, 2014 at 06:56:24PM +0800, Ming Lei wrote: > Hi Fengguang, > > On Fri, Jan 17, 2014 at 6:20 PM, Fengguang Wu <fengguang.wu@intel.com> wrote: > > Ming Lei, > > > > We noticed that commit 74e72f894 ("lib/percpu_counter.c: fix > > __percpu_counter_add()") introduces -47.6% regression in aim7 brk_test > > on a 2S SNB server. Comparing to its parent commit: > > The commit has a bug, could you apply Hugh's patch[1] to test if > the regression can be fixed? > > If the performance regression is still there, it may be caused by bad > performance of this_cpu_add(), then I suggest you to test the patch[2] > too without enabling lockdep. > > > [1], http://marc.info/?t=138991497900001&r=1&w=2
Hugh's patch is enough to fix the kernel oops and performance regressions:
74e72f894d56eb9 0ddc13035a9b3679a0e1a2cec --------------- ------------------------- 1 ~ 0% -100.0% 0 vpx/micro/xfstests/4HDD-ext4-generic-slow2 1 ~ 0% -100.0% 0 TOTAL dmesg.This_should_not_happen_Data_will_be_lost
74e72f894d56eb9 0ddc13035a9b3679a0e1a2cec --------------- ------------------------- 71965 ~ 0% +90.4% 137038 ~ 0% lkp-snb01/micro/aim7/brk_test 71965 ~ 0% +90.4% 137038 ~ 0% TOTAL aim7.2000.jobs-per-min
In fact it turns regression to noticeable performance increase. :)
Thanks, Fengguang
> [2], http://marc.info/?l=linux-kernel&m=138909074202090&w=2 > > Thanks, > -- > Ming Lei
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