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From: "Theodore Ts'o" <tytso@mit.edu>
To: git@vger.kernel.org
Subject: Why is "git tag --contains" so slow?
Date: Wed, 30 Jun 2010 20:54:15 -0400
Message-ID: <E1OU82h-0001xY-3b@closure.thunk.org> (raw)


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.
(Yeah, or I could figure out where in the 11,631 lines of Tcl script the
"preceeds" line is calculated, but I figured I'd ask here first.)

Is there a better way of calculating what I want from the command line
using the built-in native git tools?  And if so, why is git tag
--contains apparently 4 times slower than gitk at performing this task?

Thanks,

						- Ted

             reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-01  0:54 Theodore Ts'o [this message]
2010-07-01  0:58 ` Shawn O. Pearce
2010-07-03 23:27   ` Sam Vilain
2010-07-01  1:00 ` Avery Pennarun
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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