From: Denys Vlasenko <vda.linux@googlemail.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org
Subject: Re: [PATCH] do not unroll big stuff in twofish key setup if OPTIMIZE_FOR_SIZE
Date: Wed, 24 Oct 2007 18:44:54 +0100 [thread overview]
Message-ID: <200710241844.54215.vda.linux@googlemail.com> (raw)
In-Reply-To: <20071023060748.GA27501@gondor.apana.org.au>
On Tuesday 23 October 2007 07:07, Herbert Xu wrote:
> On Sun, Oct 21, 2007 at 08:16:25PM +0100, Denys Vlasenko wrote:
> > Hello Herbert,
> >
> > Currently twofish cipher key setup code
> > has unrolled loops - approximately 70-100
> > instructions are repeated 40 times.
> >
> > As a result, twofish module is the biggest module
> > in crypto/*.
> >
> > Attached patch conditionalize this unrolling on
> > CONFIG_CC_OPTIMIZE_FOR_SIZE. Presumably, people which
> > want to use -Os will also prefer to not have these loops
> > unrolled:
>
> Thanks for the patch Denys.
>
> Have you looked at the performance figures on x86 for the two
> variants? If the difference is small we could just get rid of
> the unrolled version altogether.
7% slower key setup (see patch - there is a comment about it).
--
vda
next prev parent reply other threads:[~2007-10-24 17:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-21 19:16 [PATCH] do not unroll big stuff in twofish key setup if OPTIMIZE_FOR_SIZE Denys Vlasenko
2007-10-23 6:07 ` Herbert Xu
2007-10-24 17:44 ` Denys Vlasenko [this message]
2007-10-25 1:08 ` Herbert Xu
2007-10-25 18:33 ` Denys Vlasenko
2007-10-26 8:24 ` Herbert Xu
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