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From: Linus Torvalds <torvalds@osdl.org>
To: Petr Baudis <pasky@suse.cz>
Cc: Junio C Hamano <junkio@cox.net>,
	Peter Eriksen <s022018@student.dtu.dk>,
	Git Mailing List <git@vger.kernel.org>
Subject: Re: Bottlenecks in git merge
Date: Tue, 31 Jan 2006 17:04:00 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0601311701000.7301@g5.osdl.org> (raw)
In-Reply-To: <20060201005035.GD31278@pasky.or.cz>



On Wed, 1 Feb 2006, Petr Baudis wrote:
> 
> xpasky@machine[0:0]~/linux-2.6.git$ echo -e '#!/bin/sh\n/bin/true' >r && chmod a+x r
> xpasky@machine[0:0]~/linux-2.6.git$ time git-merge-index -o ./r -a
> 
> real    0m3.827s
> user    0m1.788s
> sys     0m2.004s
> xpasky@machine[0:0]~/linux-2.6.git$ time git-merge-index -o ~/git-pb/git-merge-one-file -a
> [lots of "Removing"]
> 
> real    1m21.773s
> user    0m30.806s
> sys     0m13.248s
> 
> The costs are apparently in git-update-index, not in the shell.

Btw, this is where "oprofile" really shines. You can get exact listings of 
which symbols in which programs are taking up CPU-time, even when the time 
is spent in hundreds of different executions of a program.

Me, I'm too lazy to use it often, but not too lazy to point others towards 
it.

You do need to have kernel support for it compiled in, and it works better 
on certain CPU's (that have supported counters) than on others.

		Linus

  reply	other threads:[~2006-02-01  1:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-31 21:33 Bottlenecks in git merge Peter Eriksen
2006-01-31 23:06 ` Junio C Hamano
2006-01-31 23:35   ` Petr Baudis
2006-02-01  0:43     ` Junio C Hamano
2006-01-31 23:45   ` Linus Torvalds
2006-02-01  0:50     ` Petr Baudis
2006-02-01  1:04       ` Linus Torvalds [this message]
2006-01-31 23:27 ` Petr Baudis
2006-02-04  7:31 ` [PATCH] read-tree --aggressive Junio C Hamano
2006-02-04 11:52   ` Peter Eriksen
2006-02-04 12:56   ` Junio C Hamano

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