From: Avery Pennarun <apenwarr@gmail.com>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: git@vger.kernel.org
Subject: Re: Why is "git tag --contains" so slow?
Date: Wed, 30 Jun 2010 21:00:21 -0400 [thread overview]
Message-ID: <AANLkTikkLIKm3soF9agXnN34P7Xnq4AiVqGU_qFaaRmZ@mail.gmail.com> (raw)
In-Reply-To: <E1OU82h-0001xY-3b@closure.thunk.org>
On Wed, Jun 30, 2010 at 8:54 PM, Theodore Ts'o <tytso@mit.edu> wrote:
> I'm trying to write a script that can determine the first kernel release
> (i.e., a tag of that matchs v2.6.*) that contains a particular commit.
>
> I can do this using "git tag --contains <commit-id>", but it's quite
> slow. It takes something like 8-9 seconds. (8.5 seconds of user time,
> 8.6 times of wall clock, to be precise).
>
> I can get the information much faster using "gitk -1 <commit-id>", which
> finishes painting the screen in under 2 seconds, but that throws up a
> GUI and then a human has to pull the information out using their eyes.
There's a big difference between the two: the gitk command you're
using only works if the given commit is *itself* named by a tag, while
'git tag --contains' needs to search the entire history of every tag
to see if the given commit is *inside* it somewhere.
If all you want is to see if a given commit exactly matches a tag,
perhaps you want something like
git describe --exact-match <commit-id>
Have fun,
Avery
next prev parent reply other threads:[~2010-07-01 1:00 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-01 0:54 Why is "git tag --contains" so slow? Theodore Ts'o
2010-07-01 0:58 ` Shawn O. Pearce
2010-07-03 23:27 ` Sam Vilain
2010-07-01 1:00 ` Avery Pennarun [this message]
2010-07-01 12:17 ` tytso
2010-07-01 15:03 ` Jeff King
2010-07-01 15:38 ` Jeff King
2010-07-02 19:26 ` tytso
2010-07-03 8:06 ` Jeff King
2010-07-04 0:55 ` tytso
2010-07-05 12:27 ` Jeff King
2010-07-05 12:33 ` [RFC/PATCH 1/4] tag: speed up --contains calculation Jeff King
2010-10-13 22:07 ` Jonathan Nieder
2010-10-13 22:56 ` Clemens Buchacher
2011-02-23 15:51 ` Ævar Arnfjörð Bjarmason
2011-02-23 16:39 ` Jeff King
2010-07-05 12:34 ` [RFC/PATCH 2/4] limit "contains" traversals based on commit timestamp Jeff King
2010-10-13 23:21 ` Jonathan Nieder
2010-07-05 12:35 ` [RFC/PATCH 3/4] default core.clockskew variable to one day Jeff King
2010-07-05 12:36 ` [RFC/PATCH 4/4] name-rev: respect core.clockskew Jeff King
2010-07-05 12:39 ` Why is "git tag --contains" so slow? Jeff King
2010-10-14 18:59 ` Jonathan Nieder
2010-10-16 14:32 ` Clemens Buchacher
2010-10-27 17:11 ` Jeff King
2010-10-28 8:07 ` Clemens Buchacher
2010-07-05 14:10 ` tytso
2010-07-06 11:58 ` Jeff King
2010-07-06 15:31 ` Will Palmer
2010-07-06 16:53 ` tytso
2010-07-08 11:28 ` Jeff King
2010-07-08 13:21 ` Will Palmer
2010-07-08 13:54 ` tytso
2010-07-07 17:45 ` Jeff King
2010-07-08 10:29 ` Theodore Tso
2010-07-08 11:12 ` Jakub Narebski
2010-07-08 19:29 ` Nicolas Pitre
2010-07-08 19:39 ` Avery Pennarun
2010-07-08 20:13 ` Nicolas Pitre
2010-07-08 21:20 ` Jakub Narebski
2010-07-08 21:30 ` Sverre Rabbelier
2010-07-08 23:10 ` Nicolas Pitre
2010-07-08 23:15 ` Nicolas Pitre
2010-07-08 11:31 ` Jeff King
2010-07-08 14:35 ` Johan Herland
2010-07-08 19:06 ` Nicolas Pitre
2010-07-07 17:50 ` Jeff King
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