Re: [percpu_counter] 74e72f894: -47.6% aim7 jobs-per-min

From: Ming Lei
Date: Fri Jan 17 2014 - 05:56:30 EST

Hi Fengguang,

On Fri, Jan 17, 2014 at 6:20 PM, Fengguang Wu <fengguang.wu@xxxxxxxxx> 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.


Ming Lei
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