Messages in this thread | | | Date | Sun, 27 Mar 2016 17:20:05 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 3/5] perf core: Prepare writing into ring buffer from end |
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On Fri, Mar 25, 2016 at 10:14:36PM +0800, Wangnan (F) wrote: > >>I think you enabled some unusual config options?
x86_64-defconfig
> >You must enabled CONFIG_OPTIMIZE_INLINING. Now I get similar result:
It has that indeed.
> After enabling CONFIG_OPTIMIZE_INLINING: > > Test its performance by calling 'close(-1)' for 3000000 times and > use 'perf record -o /dev/null -e raw_syscalls:* test-ring-buffer' to > capture system calls: > > MEAN STDVAR > BASE 800077.1 23448.13 > RAWPERF.PRE 2465858.0 603473.70 > RAWPERF.POST 2471925.0 609437.60 > > Considering the high stdvar, after applying this patch the performance > is not change.
Why is your variance so immense? And doesn't that render the measurements pointless?
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