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From: Mel Gorman <mgorman@techsingularity.net>
To: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org,
	Matt Fleming <matt@codeblueprint.co.uk>
Subject: Re: [PATCH] sched: Only migrate tasks due to interrupts on an idle CPU if prev and target CPUs share cache
Date: Sat, 16 Dec 2017 18:28:08 +0000	[thread overview]
Message-ID: <20171216182808.gc63wdzpxqw5p732@techsingularity.net> (raw)
In-Reply-To: <1513370286.11185.136.camel@gmx.de>

On Fri, Dec 15, 2017 at 09:38:06PM +0100, Mike Galbraith wrote:
> On Fri, 2017-12-15 at 16:52 +0000, Mel Gorman wrote:
> > 
> > It's a small improvement...
> 
> From my log on corr.arch.suse.de (2x8 box)
> 
> 4.15.0.g2db767d-default
> Throughput 2665.88 MB/sec  8 clients  8 procs  max_latency=21.472 ms
> 4.15.0.g2db767d-default NO_WA_IDLE
> Throughput 3416.35 MB/sec  8 clients  8 procs  max_latency=9.825 ms
> 
> Not so small improvement.  WA_IDLE ripped corr up pretty bad, turning
> it off restored 4.4 performance.
> 

Sounds plausible. I expect it depends on the remote access latency as
well as whether the data gets prefetched fast enough.

-- 
Mel Gorman
SUSE Labs

      reply	other threads:[~2017-12-16 18:28 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-15 16:52 Mel Gorman
2017-12-15 20:38 ` Mike Galbraith
2017-12-16 18:28   ` Mel Gorman [this message]

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