linux-kernel - Re: [PATCH v2 0/4] locking/mutex: Enable optimistic spinning of lock waiter

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Message-ID: <20160216085111.GR6357@twins.programming.kicks-ass.net>
Date:	Tue, 16 Feb 2016 09:51:11 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Waiman Long <Waiman.Long@....com>
Cc:	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ding Tianhong <dingtianhong@...wei.com>,
	Jason Low <jason.low2@....com>,
	Davidlohr Bueso <dave@...olabs.net>,
	"Paul E. McKenney" <paulmck@...ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Will Deacon <Will.Deacon@....com>,
	Tim Chen <tim.c.chen@...ux.intel.com>
Subject: Re: [PATCH v2 0/4] locking/mutex: Enable optimistic spinning of lock
 waiter

On Fri, Feb 12, 2016 at 12:32:11PM -0500, Waiman Long wrote:
> My own test on a 4-socket E7-4820 v3 system showed a regression of
> about 4% in the high_systime workload with Peter's patch which this
> new patch effectively eliminates.
> 
> Testing on an 8-socket Westmere-EX server, however, has performance
> change from -9% to than +140% on the fserver workload of AIM7
> depending on how the system was set up.

Subject: [lkp] [locking/mutex] aaca135480: -72.9% fsmark.files_per_sec

My patch also generated the above email.

Please also test that benchmark against this approach.