From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Anton Blanchard <anton@ozlabs.org>,
benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com,
cyrilbur@gmail.com
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: powerpc: During context switch, check before setting mm_cpumask
Date: Wed, 5 Oct 2016 13:36:29 +1100 (AEDT) [thread overview]
Message-ID: <3spfzx28DDz9sCg@ozlabs.org> (raw)
In-Reply-To: <1475476829-6296-1-git-send-email-anton@ozlabs.org>
On Mon, 2016-03-10 at 06:40:29 UTC, Anton Blanchard wrote:
> From: Anton Blanchard <anton@samba.org>
>
> During context switch, switch_mm() sets our current CPU in mm_cpumask.
> We can avoid this atomic sequence in most cases by checking before
> setting the bit.
>
> Testing on a POWER8 using our context switch microbenchmark:
>
> tools/testing/selftests/powerpc/benchmarks/context_switch \
> --process --no-fp --no-altivec --no-vector
>
> Performance improves 2%.
>
> Signed-off-by: Anton Blanchard <anton@samba.org>
> Acked-by: Balbir Singh <bsingharora@gmail.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/bb85fb5803270c52863b983596c2a0
cheers
prev parent reply other threads:[~2016-10-05 2:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-03 6:40 [PATCH] powerpc: During context switch, check before setting mm_cpumask Anton Blanchard
2016-10-03 23:25 ` Balbir Singh
2016-10-03 23:58 ` Benjamin Herrenschmidt
2016-10-04 0:20 ` Balbir Singh
2016-10-05 2:36 ` Michael Ellerman [this message]
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