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From: Joachim B Haga <cjhaga@fys.uio.no>
To: git@vger.kernel.org
Subject: Re: Some git performance measurements..
Date: Sat, 01 Dec 2007 12:36:04 +0100	[thread overview]
Message-ID: <85abou8x5n.fsf@lupus.ig3.net> (raw)
In-Reply-To: alpine.LFD.0.9999.0711281852160.8458@woody.linux-foundation.org

Linus Torvalds <torvalds@linux-foundation.org> writes:

> The pack-files (both index and data) are accessed somewhat randomly, but 
> there is still enough locality that doing read-ahead and clustering really 
> does help.

They are dense enough that slurping them in whole is 20% faster, at 
least here. And much less noisy! These are both cache-cold tests.

$ time git read-tree -m -u HEAD HEAD

real    0m9.255s
user    0m0.832s
sys     0m0.196s

$ time (cat .git/objects/pack/* .git/index >/dev/null; git read-tree -m -u HEAD HEAD)

real    0m7.141s
user    0m0.936s
sys     0m1.912s


Now, I don't know how useful this is since git doesn't know if the
data are cached. Is it perhaps possible to give a hint to the
readahead logic that it should try to read as far as possible?


-j.

  parent reply	other threads:[~2007-12-01 11:36 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-29  2:49 Some git performance measurements Linus Torvalds
2007-11-29  3:14 ` Linus Torvalds
2007-11-29  3:59   ` Nicolas Pitre
2007-11-29  4:32     ` Linus Torvalds
2007-11-29 17:25       ` Nicolas Pitre
2007-11-29 17:48         ` Linus Torvalds
2007-11-29 18:52           ` Nicolas Pitre
2007-11-30  5:00           ` Junio C Hamano
2007-11-30  6:03             ` Linus Torvalds
2007-11-30  0:54         ` Jakub Narebski
2007-11-30  2:21           ` Linus Torvalds
2007-11-30  2:39             ` Jakub Narebski
2007-11-30  2:40             ` Nicolas Pitre
2007-11-30  6:11               ` Steffen Prohaska
2007-12-07 13:35                 ` Mike Ralphson
2007-12-07 13:49                   ` Johannes Schindelin
2007-12-07 16:07                     ` Linus Torvalds
2007-12-07 16:09                     ` Mike Ralphson
2007-12-07 18:37                       ` Johannes Schindelin
2007-12-07 19:15                         ` Mike Ralphson
2007-12-08 11:05                           ` Johannes Schindelin
2007-12-08 23:04                             ` Brian Downing
2007-11-30  2:54             ` Linus Torvalds
2007-12-05  1:04               ` Federico Mena Quintero
2007-12-01 11:36   ` Joachim B Haga [this message]
2007-12-01 17:19     ` Linus Torvalds
2007-11-29  5:17 ` Junio C Hamano
2007-11-29 10:17   ` [PATCH] per-directory-exclude: lazily read .gitignore files Junio C Hamano

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