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From: Jeff King <peff@peff.net>
To: "René Scharfe" <l.s.r@web.de>
Cc: Jonathan Nieder <jrnieder@gmail.com>,
	Git Mailing List <git@vger.kernel.org>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH] fast-import: use hashcmp() for SHA1 hash comparison
Date: Fri, 18 Jul 2014 19:57:08 -0400	[thread overview]
Message-ID: <20140718235706.GA11192@peff.net> (raw)
In-Reply-To: <53C971FD.6040500@web.de>

On Fri, Jul 18, 2014 at 09:14:05PM +0200, René Scharfe wrote:

> If inlining is really better is another matter; I don't understand how
> 1a812f3a (hashcmp(): inline memcmp() by hand to optimize) could have made
> git gc 18% faster, as it claimed.  I would expect memcmp(), which can
> compare more than a byte at a time, to be significantly faster -- or at
> least just as fast as whatever the compiler does with the inlined version.

I looked into this a while ago[1]. I think with glibc 2.13 and up, the
memcmp is a win. We should consider switching back if that is what is
common now.

-Peff

[1] http://article.gmane.org/gmane.comp.version-control.git/218396

  reply	other threads:[~2014-07-18 23:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-18 16:00 [PATCH] fast-import: use hashcmp() for SHA1 hash comparison René Scharfe
2014-07-18 18:42 ` Jonathan Nieder
2014-07-18 19:14   ` René Scharfe
2014-07-18 23:57     ` Jeff King [this message]
2014-07-19 12:11       ` René Scharfe
2014-07-19 16:43         ` brian m. carlson
2014-07-19 17:53           ` René Scharfe

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