From: "Alex Bennée" <kernel-hacker@bennee.com>
To: Ramkumar Ramachandra <artagnon@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: Poor performance of git describe in big repos
Date: Thu, 30 May 2013 14:09:42 +0100 [thread overview]
Message-ID: <CAJ-05NNAeLUfyk8+NU8PmjKqfTcZ1NT_NPAk3M1QROtzsQKJ8g@mail.gmail.com> (raw)
In-Reply-To: <CALkWK0ndKMZRuWgdg6djqPUGxbDAqZPcv2q0qPrv_2b=1NEM5g@mail.gmail.com>
It looks like it's a file caching effect combined with my repo being
more pathalogical in size and contents. Note run 1 (cold) vs run 2 on
the linux file tree:
13:52 ajb@sloy/x86_64 [linux.git] >time git describe --debug --long
--tags HEAD~10000
searching to describe HEAD~10000
annotated 57 v2.6.34-rc2
annotated 1688 v2.6.34-rc1
annotated 7932 v2.6.33
annotated 8157 v2.6.33-rc8
annotated 8381 v2.6.33-rc7
annotated 8637 v2.6.33-rc6
annotated 8964 v2.6.33-rc5
annotated 9493 v2.6.33-rc4
annotated 9912 v2.6.33-rc3
annotated 10202 v2.6.33-rc2
traversed 10547 commits
more than 10 tags found; listed 10 most recent
gave up search at 55639353a0035052d9ea6cfe4dde0ac7fcbb2c9f
v2.6.34-rc2-57-gef5da59
real 0m7.332s
user 0m0.308s
sys 0m0.244s
14:03 ajb@sloy/x86_64 [linux.git] >time git describe --debug --long
--tags HEAD~10000
searching to describe HEAD~10000
annotated 57 v2.6.34-rc2
annotated 1688 v2.6.34-rc1
annotated 7932 v2.6.33
annotated 8157 v2.6.33-rc8
annotated 8381 v2.6.33-rc7
annotated 8637 v2.6.33-rc6
annotated 8964 v2.6.33-rc5
annotated 9493 v2.6.33-rc4
annotated 9912 v2.6.33-rc3
annotated 10202 v2.6.33-rc2
traversed 10547 commits
more than 10 tags found; listed 10 most recent
gave up search at 55639353a0035052d9ea6cfe4dde0ac7fcbb2c9f
v2.6.34-rc2-57-gef5da59
real 0m0.298s
user 0m0.244s
sys 0m0.036s
Although the perf profile looks subtly different.
First through the linux tree:
22.35% git libz.so.1.2.3.4 [.] inflate
18.56% git libz.so.1.2.3.4 [.] inflate_fast
17.48% git libz.so.1.2.3.4 [.] inflate_table
7.84% git git [.] hashcmp
3.93% git git [.] get_sha1_hex
3.46% git libz.so.1.2.3.4 [.] adler32
And through my "special" repo:
41.58% git libcrypto.so.1.0.0 [.] sha1_block_data_order_ssse3
33.62% git libz.so.1.2.3.4 [.] inflate_fast
10.39% git libz.so.1.2.3.4 [.] adler32
2.03% git [kernel.kallsyms] [k] clear_page_c
I'm not sure why libcrypto features so highly in the results
--
Alex.
On 30 May 2013 12:33, Ramkumar Ramachandra <artagnon@gmail.com> wrote:
> Alex Bennée wrote:
>>>time /usr/bin/git --no-pager
>> traversed 223 commits
>>
>> real 0m4.817s
>> user 0m4.320s
>> sys 0m0.464s
>
> I'm quite clueless about why it is taking this long: I think it's IO
> because there's nothing to compute? I really can't trace anything
> unless you can reproduce it on a public repository. On linux.git with
> my rotating hard disk:
>
> $ time git describe --debug --long --tags HEAD~10000
> searching to describe HEAD~10000
> annotated 5445 v2.6.33
> annotated 5660 v2.6.33-rc8
> annotated 5884 v2.6.33-rc7
> annotated 6140 v2.6.33-rc6
> annotated 6467 v2.6.33-rc5
> annotated 6999 v2.6.33-rc4
> annotated 7430 v2.6.33-rc3
> annotated 7746 v2.6.33-rc2
> annotated 8212 v2.6.33-rc1
> annotated 13854 v2.6.32
> traversed 18895 commits
> more than 10 tags found; listed 10 most recent
> gave up search at 648f4e3e50c4793d9dbf9a09afa193631f76fa26
> v2.6.33-5445-ge7c84ee
>
> real 0m0.509s
> user 0m0.470s
> sys 0m0.037s
>
> 18k+ commits traversed in half a second here, so I really don't know
> what is going on.
--
Alex, homepage: http://www.bennee.com/~alex/
next prev parent reply other threads:[~2013-05-30 13:09 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-30 10:38 Poor performance of git describe in big repos Alex Bennée
2013-05-30 11:33 ` Ramkumar Ramachandra
2013-05-30 13:09 ` Alex Bennée [this message]
2013-05-30 14:32 ` Ramkumar Ramachandra
2013-05-30 15:01 ` Alex Bennée
2013-05-30 15:17 ` Ramkumar Ramachandra
2013-05-30 15:33 ` Thomas Rast
2013-05-30 16:01 ` Alex Bennée
2013-05-30 16:21 ` Thomas Rast
2013-05-30 16:44 ` Thomas Rast
2013-05-30 19:01 ` Antoine Pelisse
2013-05-30 20:00 ` [PATCH 1/2] sha1_file: silence sha1_loose_object_info Thomas Rast
2013-05-30 20:00 ` [PATCH 2/2] lookup_commit_reference_gently: do not read non-{tag,commit} Thomas Rast
2013-05-30 21:22 ` Jeff King
2013-05-31 0:52 ` Duy Nguyen
2013-05-31 8:08 ` Thomas Rast
2013-05-31 16:00 ` Jeff King
2013-05-31 6:43 ` Ramkumar Ramachandra
2013-05-31 8:16 ` Thomas Rast
2013-05-30 19:30 ` Poor performance of git describe in big repos John Keeping
2013-05-31 8:14 ` Alex Bennée
2013-05-31 8:24 ` Thomas Rast
2013-05-31 8:40 ` Alex Bennée
2013-05-31 8:46 ` Thomas Rast
2013-05-31 9:57 ` Alex Bennée
2013-06-03 8:02 ` Alex Bennée
2013-06-03 16:32 ` Junio C Hamano
2013-06-03 17:48 ` Junio C Hamano
2013-05-31 10:27 ` Thomas Rast
2013-05-31 16:17 ` Jeff King
2013-06-03 8:39 ` Alex Bennée
2013-06-03 14:49 ` Jeff King
2013-05-31 8:32 ` John Keeping
2013-05-31 8:49 ` Alex Bennée
2013-05-31 8:59 ` John Keeping
2013-05-30 11:48 ` John Keeping
2013-05-30 12:29 ` Alex Bennée
2013-05-30 13:20 ` Duy Nguyen
[not found] ` <CAJ-05NPacjAEC99Ntd9eMnTD9_PMMYFob-_tAx5CeSB79TkRSg@mail.gmail.com>
2013-05-30 13:45 ` Duy Nguyen
2013-05-30 14:02 ` Alex Bennée
2013-05-30 13:16 ` Alex Bennée
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