From: Michael J Gruber <git@drmicha.warpmail.net>
To: Marat Radchenko <marat@slonopotamus.org>
Cc: git@vger.kernel.org
Subject: Re: What's the difference between `git show branch:file | diff -u - file` vs `git diff branch file`?
Date: Tue, 23 Aug 2011 17:34:50 +0200 [thread overview]
Message-ID: <4E53C89A.9000604@drmicha.warpmail.net> (raw)
In-Reply-To: <1314096731.15017.2.camel@n900.home.ru>
Marat Radchenko venit, vidit, dixit 23.08.2011 12:52:
>> Is that a very large tree or a very slow file system?
> Tree is large (500k files), file system is irrelevant since all time is spend on CPU.
>
>> Do we enumerate all
>> differing files and only then limit diff output by path??
>
> Dunno, that's why I am asking why it is so slow.
Well, we have to read the full tree before diffing. But I can't
reproduce the extreme difference which you observed (0.003s vs. 30s),
only a factor of ten or so for a repo with 100k files:
git init
seq 0 100000|while read n ; do echo a > a$n;done
git add .
git commit -m m
echo b > a0
On a ramdisk, I get:
time git diff > /dev/null
real 0m0.160s
user 0m0.064s
sys 0m0.190s
time git diff -- a0 > /dev/null
real 0m0.070s
user 0m0.051s
sys 0m0.021s
time git diff HEAD > /dev/null
real 0m0.266s
user 0m0.145s
sys 0m0.212s
time git diff HEAD -- a0 > /dev/null
real 0m0.171s
user 0m0.136s
sys 0m0.033s
time git show HEAD:a0 > /dev/null
real 0m0.018s
user 0m0.009s
sys 0m0.007s
time git show HEAD:a0 | diff -u - a0 > /dev/null
real 0m0.019s
user 0m0.010s
sys 0m0.008s
Stumped.
In your case, do you have a lot of differing files besides the one you
are limitting to? Anyway, that does not seem to make a huge difference
in my timings. (Just tried.) Still Stumped.
Michael
next prev parent reply other threads:[~2011-08-23 15:35 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-23 7:25 What's the difference between `git show branch:file | diff -u - file` vs `git diff branch file`? Marat Radchenko
2011-08-23 10:03 ` Michael J Gruber
2011-08-23 10:52 ` Marat Radchenko
2011-08-23 15:20 ` Michael Witten
2011-08-23 15:34 ` Michael J Gruber [this message]
2011-08-23 16:45 ` Marat Radchenko
2011-08-23 17:15 ` Junio C Hamano
2011-08-23 18:21 ` Marat Radchenko
2011-08-23 20:07 ` Michael J Gruber
2011-08-25 16:09 ` Marat Radchenko
2011-08-25 21:10 ` Junio C Hamano
2011-08-26 9:43 ` Marat Radchenko
2011-08-29 7:41 ` Nguyen Thai Ngoc Duy
2011-08-29 14:48 ` Marat Radchenko
2011-08-29 16:09 ` Nguyen Thai Ngoc Duy
2011-08-29 17:18 ` Junio C Hamano
2011-08-29 20:42 ` Junio C Hamano
2011-08-29 20:50 ` Junio C Hamano
2011-08-29 21:09 ` Junio C Hamano
2011-08-29 21:33 ` [PATCH 0/3] Un-pessimize "diff-index $commit -- $pathspec" Junio C Hamano
2011-08-29 21:33 ` [PATCH 1/3] traverse_trees(): allow pruning with pathspec Junio C Hamano
2011-08-30 12:53 ` Nguyen Thai Ngoc Duy
2011-08-30 17:44 ` Junio C Hamano
2011-08-31 1:35 ` Nguyen Thai Ngoc Duy
2011-10-09 15:39 ` Michael Haggerty
2011-10-09 21:35 ` Nguyen Thai Ngoc Duy
2011-10-10 4:42 ` Michael Haggerty
2011-08-29 21:33 ` [PATCH 2/3] unpack-trees: " Junio C Hamano
2011-08-30 13:03 ` Nguyen Thai Ngoc Duy
2011-08-30 17:32 ` Junio C Hamano
2011-08-30 15:24 ` David Michael Barr
2011-08-29 21:33 ` [PATCH 3/3] diff-index: pass pathspec down to unpack-trees machinery Junio C Hamano
2012-01-11 6:31 ` Jonathan Nieder
2012-01-11 8:05 ` Junio C Hamano
2012-01-11 12:33 ` Nguyen Thai Ngoc Duy
2012-01-11 12:47 ` Nguyen Thai Ngoc Duy
2012-01-11 20:40 ` Junio C Hamano
2012-01-12 4:09 ` [PATCH] tree_entry_interesting: make recursive mode default Nguyễn Thái Ngọc Duy
2012-01-12 5:04 ` Junio C Hamano
2012-01-12 5:44 ` Nguyen Thai Ngoc Duy
2012-01-14 9:23 ` [PATCH v2 1/2] Document limited recursion pathspec matching with wildcards Nguyễn Thái Ngọc Duy
2012-01-14 9:23 ` [PATCH v2 2/2] tree_entry_interesting: make recursive mode default Nguyễn Thái Ngọc Duy
2012-01-15 3:12 ` Junio C Hamano
2012-01-15 10:03 ` Nguyen Thai Ngoc Duy
2012-01-16 22:15 ` Junio C Hamano
2012-01-18 8:59 ` Nguyen Thai Ngoc Duy
2012-01-15 2:38 ` [PATCH v2 1/2] Document limited recursion pathspec matching with wildcards Junio C Hamano
2012-01-15 9:48 ` Nguyen Thai Ngoc Duy
2011-08-29 21:56 ` [PATCH 0/3] Un-pessimize "diff-index $commit -- $pathspec" Linus Torvalds
2011-08-29 22:05 ` Junio C Hamano
2011-08-29 22:11 ` Linus Torvalds
2011-08-29 23:42 ` Junio C Hamano
2011-08-30 6:16 ` Marat Radchenko
2011-08-31 0:18 ` Junio C Hamano
2011-08-30 10:04 ` Michael J Gruber
2011-08-30 17:03 ` Junio C Hamano
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