From: Thomas Rast <trast@student.ethz.ch>
To: Jeff King <peff@peff.net>
Cc: <git@vger.kernel.org>, Junio C Hamano <gitster@pobox.com>,
Laine Walker-Avina <lwalkera@pasco.com>
Subject: Re: [PATCH] rebase -i: avoid --cherry-pick when rebasing to a direct ancestor
Date: Sat, 20 Feb 2010 14:38:29 +0100 [thread overview]
Message-ID: <201002201438.29635.trast@student.ethz.ch> (raw)
In-Reply-To: <20100220072728.GA12168@coredump.intra.peff.net>
On Saturday 20 February 2010 08:27:28 Jeff King wrote:
> But it is probably the source of the slowness to xdiff that
> gigantic files.
BTW, here's a weird data point:
$ ls -l a b
-rw-r--r-- 1 thomas users 3300765 2010-02-20 12:48 a
-rw-r--r-- 1 thomas users 3253762 2010-02-20 12:48 b
$ time diff -u a b | wc -l
54530
real 0m0.644s
user 0m0.562s
sys 0m0.044s
$ time git diff --no-index a b >/dev/null
real 0m22.848s
user 0m21.956s
sys 0m0.137s
$ time git diff --no-index --patience a b >/dev/null
real 0m19.508s
user 0m18.673s
sys 0m0.273s
'a' and 'b' are two pnm's as per the OPs specification, I made 'a' a
gradient and 'b' the same with two crosses drawn over it. You can
find them at
http://thomasrast.ch/download/slow-diff-pnms.zip
if you want to reproduce.
So what on earth does 'diff' do that makes it 35 times as fast?
--
Thomas Rast
trast@{inf,student}.ethz.ch
next prev parent reply other threads:[~2010-02-20 13:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-19 21:24 Git has bad performance when traversing change-sets with large PPM files Laine Walker-Avina
2010-02-19 23:30 ` [PATCH] rebase -i: avoid --cherry-pick when rebasing to a direct ancestor Thomas Rast
2010-02-20 0:02 ` Thomas Rast
2010-02-20 7:27 ` Jeff King
2010-02-20 11:42 ` [PATCH] cherry_pick_list: quit early if one side is empty Thomas Rast
2010-02-21 6:50 ` Jeff King
2010-02-20 13:38 ` Thomas Rast [this message]
2010-02-21 7:46 ` [PATCH] rebase -i: avoid --cherry-pick when rebasing to a direct ancestor Jeff King
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