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Re: [PATCH 33/37] perf bench futex: Cache align the worker struct

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH 33/37] perf bench futex: Cache align the worker struct
Date 2016-10-24 21:00 +0200
Message-ID <svSDx-34S-55@gated-at.bofh.it> (permalink)
References <svQil-1Di-3@gated-at.bofh.it> <svQil-1Di-1@gated-at.bofh.it> <svSDx-34S-57@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Em Mon, Oct 24, 2016 at 11:50:50AM -0700, Davidlohr Bueso escreveu:
> On 2016-10-24 09:20, Arnaldo Carvalho de Melo wrote:
> > From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> > 
> > It popped up in perf testing that the worker consumes some amount of
> > CPU. It boils down to the increment of `ops` which causes cache line
> > bouncing between the individual threads.
> > 
> > This patch aligns the struct by 256 bytes to ensure that not a cache
> > line is shared among CPUs. 128 byte is the x86 worst case and grep says
> > that L1_CACHE_SHIFT is set to 8 on s390.
> 
> Hmm so this one should have been replaced with this:
> 
> https://marc.info/?l=linux-kernel&m=147690008801082

Humm, sorry, can you please send a patch fixing this?

- Arnaldo

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[PATCH 33/37] perf bench futex: Cache align the worker struct Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-24 18:30 +0200
  Re: [PATCH 33/37] perf bench futex: Cache align the worker struct Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-24 21:00 +0200
  Re: [PATCH 33/37] perf bench futex: Cache align the worker struct Davidlohr Bueso <dbueso@suse.de> - 2016-10-24 21:10 +0200

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