From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Anton Blanchard <anton@samba.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Mackerras <paulus@samba.org>,
acsawdey@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 2/2] powerpc: Align hot loops of some string functions
Date: Thu, 26 May 2016 14:37:28 -0500 [thread overview]
Message-ID: <20160526193728.GA883@gate.crashing.org> (raw)
In-Reply-To: <14a46745-dd1e-2963-1c1a-7daafa5aed4b@c-s.fr>
On Thu, May 26, 2016 at 09:24:51AM +0200, Christophe Leroy wrote:
> Wouldn't it be better to add nops before the function entry in order to
> get the hot loop aligned, instead of adding nops in the middle of the
> function ?
Why would that be better? The nops are executed once per function call
in either case, there are the same number of nops in either case, and
on most CPUs nops aren't actually executed anyway (they are decoded and
the thrown away).
Segher
next prev parent reply other threads:[~2016-05-26 19:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 22:38 [PATCH 1/2] powerpc: Remove assembly versions of strcpy, strcat, strlen and strcmp Anton Blanchard
2016-05-25 22:39 ` [PATCH 2/2] powerpc: Align hot loops of some string functions Anton Blanchard
2016-05-26 7:24 ` Christophe Leroy
2016-05-26 19:37 ` Segher Boessenkool [this message]
2016-05-27 5:45 ` Christophe Leroy
2016-05-27 6:26 ` Segher Boessenkool
2016-06-15 12:39 ` [2/2] " Michael Ellerman
2016-06-15 12:39 ` [1/2] powerpc: Remove assembly versions of strcpy, strcat, strlen and strcmp Michael Ellerman
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