Date: Tue, 22 Mar 2016 10:59:12 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <waiman.long@hpe.com>
Cc: Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ding Tianhong <dingtianhong@huawei.com>,
        Jason Low <jason.low2@hpe.com>, Davidlohr Bueso <dave@stgolabs.net>,
        "Paul E. McKenney" <paulmck@us.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <Will.Deacon@arm.com>,
        Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH v2 0/4] locking/mutex: Enable optimistic spinning of lock
 waiter
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On Mon, Mar 21, 2016 at 11:19:02PM -0400, Waiman Long wrote:
> Instead, the subject was
> 
> [lkp] [locking/mutex] 5267438002: +38.9%
> fileio.time.involuntary_context_switches
> 
>       4409 ?  1%     +38.9%       6126 ?  2%
> fileio.time.involuntary_context_switches
>       6.00 ?  0%     +33.3%       8.00 ?  0%
> fileio.time.percent_of_cpu_this_job_got
>      36.06 ?  0%     +43.0%      51.55 ?  0%  fileio.time.system_time
>    1828660 ?  0%     -92.5%     137258 ?  0%
> fileio.time.voluntary_context_switches
> 
> Given that the number of voluntary context switches dropped by 92.5%, an
> increase in involuntary context switches that is order of magnitude less
> than the voluntary context switches should be OK, I think.
> 
> Do you know how to report back that this increase is expected and is nothing
> to worry about? Do I just reply it back?

Nah, just ignore.