Re: [Question]: try to fix contention between expire_timers and try_to_del_timer_sync

From	Vikram Mulukutla <markivx@codeaurora.org>
Newsgroups	linux.kernel
Subject	Re: [Question]: try to fix contention between expire_timers and try_to_del_timer_sync
Date	2017-08-04 01:30 +0200
Message-ID	<uaxIZ-76G-1@gated-at.bofh.it> (permalink)
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Hi Will,

On 2017-07-31 06:13, Will Deacon wrote:
> Hi Vikram,
> 
> On Fri, Jul 28, 2017 at 12:09:38PM -0700, Vikram Mulukutla wrote:
>> On 2017-07-28 02:28, Will Deacon wrote:
>> >On Thu, Jul 27, 2017 at 06:10:34PM -0700, Vikram Mulukutla wrote:

>> >
>> This does seem to help. Here's some data after 5 runs with and without 
>> the
>> patch.
> 
> Blimey, that does seem to make a difference. Shame it's so ugly! Would 
> you
> be able to experiment with other values for CPU_RELAX_WFE_THRESHOLD? I 
> had
> it set to 10000 in the diff I posted, but that might be higher than 
> optimal.
> It would be interested to see if it correlates with num_possible_cpus()
> for the highly contended case.
> 
> Will

Sorry for the late response - I should hopefully have some more data 
with
different thresholds before the week is finished or on Monday.

Thanks,
Vikram
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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Re: [Question]: try to fix contention between expire_timers and  try_to_del_timer_sync Will Deacon <will.deacon@arm.com> - 2017-07-31 15:20 +0200
  Re: [Question]: try to fix contention between expire_timers and  try_to_del_timer_sync Vikram Mulukutla <markivx@codeaurora.org> - 2017-08-04 01:30 +0200

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