From: Johan Herland <johan@herland.net>
To: git@vger.kernel.org, spearce@spearce.org
Cc: gitster@pobox.com, Johannes.Schindelin@gmx.de,
trast@student.ethz.ch, tavestbo@trolltech.com,
git@drmicha.warpmail.net, chriscool@tuxfamily.org
Subject: Re: [PATCHv5 00/14] git notes
Date: Sat, 12 Sep 2009 17:50:00 +0200 [thread overview]
Message-ID: <200909121750.00733.johan@herland.net> (raw)
In-Reply-To: <200909080512.34634.johan@herland.net>
On Tuesday 08 September 2009, Johan Herland wrote:
> Algorithm / Notes tree git log -n10 (x100) git log --all
> ------------------------------------------------------------
> before / no-notes 4.78s 63.90s
> before / no-fanout 56.85s 65.69s
>
> 16tree / no-notes 4.77s 64.18s
> 16tree / no-fanout 30.35s 65.39s
> 16tree / 2_38 5.57s 65.42s
> 16tree / 2_2_36 5.19s 65.76s
>
> flexible / no-notes 4.78s 63.91s
> flexible / no-fanout 30.34s 65.57s
> flexible / 2_38 5.57s 65.46s
> flexible / 2_2_36 5.18s 65.72s
> flexible / ym 5.13s 65.66s
> flexible / ym_2_38 5.08s 65.63s
> flexible / ymd 5.30s 65.45s
> flexible / ymd_2_38 5.29s 65.90s
> flexible / y_m 5.11s 65.72s
> flexible / y_m_2_38 5.08s 65.67s
> flexible / y_m_d 5.06s 65.50s
> flexible / y_m_d_2_38 5.07s 65.79s
Ok, I have been pondering this back and forth, and I'm not sure what to
think. It seems allowing (not mandating) date-based fanout gives a slight
runtime advantage if used correctly, but I'm not sure the slight runtime
improvement is worth the added code complexity and worse maintainability.
I'm starting to lean against SHA1-based fanout being "good enough".
But when we look at the memory consumption, it's clear that SHA1-based
fanout loses out (because you cannot throw away subtrees without fear that
they will be needed again soon). Then again, memory consumption has not been
the major focus of the git project, and 14 MB (for holding all ~157000 notes
in the kernel repo example) is not excessive for an average desktop
computer.
Shawn, do you have any additional defence for the date-based fanout? Are
there untested reasonable scenarios that would show the benefits of date-
based fanout? How does the plan for notes usage in your code-review thingy
compare to my test scenario?
...Johan
--
Johan Herland, <johan@herland.net>
www.herland.net
next prev parent reply other threads:[~2009-09-12 15:52 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-08 2:26 [PATCHv5 00/14] git notes Johan Herland
2009-09-08 2:26 ` [PATCHv5 01/14] Introduce commit notes Johan Herland
2009-09-08 2:26 ` [PATCHv5 02/14] Add a script to edit/inspect notes Johan Herland
2009-09-08 2:26 ` [PATCHv5 03/14] Speed up git notes lookup Johan Herland
2009-09-08 2:26 ` [PATCHv5 04/14] Add an expensive test for git-notes Johan Herland
2009-09-08 2:26 ` [PATCHv5 05/14] Teach "-m <msg>" and "-F <file>" to "git notes edit" Johan Herland
2009-09-08 2:26 ` [PATCHv5 06/14] fast-import: Add support for importing commit notes Johan Herland
2009-09-08 2:26 ` [PATCHv5 07/14] t3302-notes-index-expensive: Speed up create_repo() Johan Herland
2009-09-08 2:26 ` [PATCHv5 08/14] Add flags to get_commit_notes() to control the format of the note string Johan Herland
2009-09-08 2:26 ` [PATCHv5 09/14] Add '%N'-format for pretty-printing commit notes Johan Herland
2009-09-08 2:26 ` [PATCHv5 10/14] Teach notes code to free its internal data structures on request Johan Herland
2009-09-08 2:26 ` [PATCHv5 11/14] Teach the notes lookup code to parse notes trees with various fanout schemes Johan Herland
2009-09-08 2:27 ` [PATCHv5 12/14] Selftests verifying semantics when loading notes trees with various fanouts Johan Herland
2009-09-08 2:27 ` [PATCHv5 13/14] Allow flexible organization of notes trees, using both commit date and SHA1 Johan Herland
2009-09-08 2:27 ` [PATCHv5 14/14] Add test cases for date-based fanouts Johan Herland
2009-09-08 3:12 ` [PATCHv5 00/14] git notes Johan Herland
2009-09-08 4:16 ` Junio C Hamano
2009-09-08 8:54 ` Johan Herland
2009-09-08 9:32 ` Johannes Schindelin
2009-09-08 12:36 ` Johan Herland
2009-09-08 15:53 ` Johannes Schindelin
2009-09-08 22:46 ` Johan Herland
2009-09-10 6:23 ` Stephen R. van den Berg
2009-09-10 9:25 ` Johan Herland
2009-09-08 20:31 ` Junio C Hamano
2009-09-08 21:10 ` Shawn O. Pearce
2009-09-08 21:36 ` Sverre Rabbelier
2009-09-08 21:39 ` Shawn O. Pearce
2009-09-08 21:57 ` Sverre Rabbelier
2009-09-08 21:40 ` Johan Herland
2009-09-12 15:50 ` Johan Herland [this message]
2009-09-12 18:11 ` Shawn O. Pearce
2009-09-12 18:35 ` Johan Herland
2009-09-10 14:00 ` Geert Bosch
2009-09-10 14:09 ` Michael J Gruber
2009-09-10 14:12 ` Geert Bosch
2009-09-12 0:11 ` Junio C Hamano
2009-09-12 15:52 ` Johan Herland
2009-09-12 16:08 ` [PATCHv6 " Johan Herland
2009-09-12 16:08 ` [PATCHv6 01/14] Introduce commit notes Johan Herland
2009-09-12 16:08 ` [PATCHv6 02/14] Add a script to edit/inspect notes Johan Herland
2009-09-12 16:08 ` [PATCHv6 03/14] Speed up git notes lookup Johan Herland
2009-09-12 16:08 ` [PATCHv6 04/14] Add an expensive test for git-notes Johan Herland
2009-09-12 16:08 ` [PATCHv6 05/14] Teach "-m <msg>" and "-F <file>" to "git notes edit" Johan Herland
2009-09-12 16:08 ` [PATCHv6 06/14] fast-import: Add support for importing commit notes Johan Herland
2009-09-12 16:08 ` [PATCHv6 07/14] t3302-notes-index-expensive: Speed up create_repo() Johan Herland
2009-09-12 16:08 ` [PATCHv6 08/14] Add flags to get_commit_notes() to control the format of the note string Johan Herland
2009-09-12 16:08 ` [PATCHv6 09/14] Add '%N'-format for pretty-printing commit notes Johan Herland
2009-09-12 16:08 ` [PATCHv6 10/14] Teach notes code to free its internal data structures on request Johan Herland
2009-09-12 18:40 ` Junio C Hamano
2009-09-12 22:21 ` Johan Herland
2009-09-12 16:08 ` [PATCHv6 11/14] Teach the notes lookup code to parse notes trees with various fanout schemes Johan Herland
2009-09-12 16:08 ` [PATCHv6 12/14] Selftests verifying semantics when loading notes trees with various fanouts Johan Herland
2009-09-12 16:08 ` [PATCHv6 13/14] Allow flexible organization of notes trees, using both commit date and SHA1 Johan Herland
2009-09-12 18:41 ` Junio C Hamano
2009-09-12 22:33 ` Johan Herland
2009-09-12 23:37 ` Junio C Hamano
2009-09-12 16:08 ` [PATCHv6 14/14] Add test cases for various date-based fanouts Johan Herland
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