From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@c-s.fr>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [v2] powerpc/lib: Adjust .balign inside string functions for PPC32
Date: Tue, 5 Jun 2018 00:10:58 +1000 (AEST) [thread overview]
Message-ID: <40zxg75qFJz9s5b@ozlabs.org> (raw)
In-Reply-To: <20180518130116.A1A3B6F937@po14934vm.idsi0.si.c-s.fr>
On Fri, 2018-05-18 at 13:01:16 UTC, Christophe Leroy wrote:
> commit 87a156fb18fe1 ("Align hot loops of some string functions")
> degraded the performance of string functions by adding useless
> nops
>
> A simple benchmark on an 8xx calling 100000x a memchr() that
> matches the first byte runs in 41668 TB ticks before this patch
> and in 35986 TB ticks after this patch. So this gives an
> improvement of approx 10%
>
> Another benchmark doing the same with a memchr() matching the 128th
> byte runs in 1011365 TB ticks before this patch and 1005682 TB ticks
> after this patch, so regardless on the number of loops, removing
> those useless nops improves the test by 5683 TB ticks.
>
> Fixes: 87a156fb18fe1 ("Align hot loops of some string functions")
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/1128bb7813a896bd608fb622eee3c2
cheers
prev parent reply other threads:[~2018-06-04 14:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 13:01 [PATCH v2] " Christophe Leroy
2018-06-04 14:10 ` Michael Ellerman [this message]
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