Re: [PATCH 4/7] locking/pvqspinlock: Collect slowpath lock statistics

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 4/7] locking/pvqspinlock: Collect slowpath lock statistics
Date	2015-07-12 10:30 +0200
Message-ID	<pLkO6-5ZO-1@gated-at.bofh.it> (permalink)
References	<pL9IZ-7CW-3@gated-at.bofh.it> <pL9J0-7CW-23@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Sat, Jul 11, 2015 at 04:36:55PM -0400, Waiman Long wrote:
> This patch enables the accumulation of kicking and waiting related
> PV qspinlock statistics when the new QUEUED_LOCK_STAT configuration
> option is selected. It also enables the collection of kicking and
> wakeup latencies which have a heavy dependency on the CPUs being used.
> 
> The measured latencies for different CPUs are:
> 
> 	CPU		Wakeup		Kicking
> 	---		------		-------
> 	Haswell-EX	26.4us		 9.2us
> 	Westmere-EX	99.4US		25.5us
> 
> So Haswell is much faster than Westmere.
> 
> The accumulated lock statistics will be reported in debugfs under the
> pv-qspinlock directory.

You've again stuck this behind non-trivial patches :-(
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Re: [PATCH 4/7] locking/pvqspinlock: Collect slowpath lock statistics Peter Zijlstra <peterz@infradead.org> - 2015-07-12 10:30 +0200

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