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From: Junio C Hamano <gitster@pobox.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: Really slow 'git gc'
Date: Thu, 19 Feb 2009 13:14:48 -0800	[thread overview]
Message-ID: <7vr61uku2f.fsf@gitster.siamese.dyndns.org> (raw)
In-Reply-To: <alpine.LFD.2.00.0902191200010.21686@localhost.localdomain> (Linus Torvalds's message of "Thu, 19 Feb 2009 12:24:43 -0800 (PST)")

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

> The real reason _seems_ to be the "--unpacked=pack-....pack" arguments. I 
> literally had 232 pack-files, and it looks like a lot of the time was 
> spent in that silly loop oer 'ignore_packed' in find_pack_entry(), when 
> revision.c does that "has_sha1_pack()" thing. You get a O(n**2) effect in 
> number of pack-files: for each commit we look over every pack-file, and 
> for every pack-file we look at, we look over each ignore_pack entry.

I think we can add a single bit to "struct packed_git" and in the middle
of setup_revisions() perform the O(N**2) once, so that find_pack_entry()
can check the bit without looping.

  reply	other threads:[~2009-02-19 21:16 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-19 20:24 Really slow 'git gc' Linus Torvalds
2009-02-19 21:14 ` Junio C Hamano [this message]
2009-02-19 21:25   ` Linus Torvalds
2009-02-28  9:15     ` [PATCH 0/6] "git repack -a -d" improvements Junio C Hamano
2009-02-28  9:15       ` [PATCH 1/6] git-repack: resist stray environment variable Junio C Hamano
2009-02-28  9:15       ` [PATCH 2/6] has_sha1_pack(): refactor "pretend these packs do not exist" interface Junio C Hamano
2009-02-28  9:15       ` [PATCH 3/6] has_sha1_kept_pack(): take "struct rev_info" Junio C Hamano
2009-02-28  9:15       ` [PATCH 4/6] Consolidate ignore_packed logic more Junio C Hamano
2009-02-28  9:15       ` [PATCH 5/6] Simplify is_kept_pack() Junio C Hamano
2009-02-28  9:15       ` [PATCH 6/6] is_kept_pack(): final clean-up Junio C Hamano
2009-02-28 12:29       ` [PATCH 0/6] "git repack -a -d" improvements Kjetil Barvik
2009-02-28 17:41         ` Junio C Hamano
     [not found]       ` <7Vazs5mFk91IKAarOd0wrBNmYj7eSJxVIcR0PEQxJl8R0aQmQDEqSJMphMrXhmVu570fijupQ34@cipher.nrlssc.navy.mil>
2009-03-18 20:59         ` [PATCH] t7700-repack: repack -a now works properly, expect success from test Brandon Casey
2009-03-20  3:47           ` [PATCH 0/5] repack improvements Brandon Casey
2009-03-20  3:47             ` [PATCH 1/5] t7700-repack: add two new tests demonstrating repacking flaws Brandon Casey
2009-03-20  3:47               ` [PATCH 2/5] git-repack.sh: don't use --kept-pack-only option to pack-objects Brandon Casey
2009-03-20  3:47                 ` [PATCH 3/5] pack-objects: only repack or loosen objects residing in "local" packs Brandon Casey
2009-03-20  3:47                   ` [PATCH 4/5] t7700-repack: repack -a now works properly, expect success from test Brandon Casey
2009-03-20  3:47                     ` [PATCH 5/5] Remove --kept-pack-only option and associated infrastructure Brandon Casey
2009-03-20  4:05             ` [PATCH 0/5] repack improvements Brandon Casey
2009-02-19 21:34   ` Really slow 'git gc' Junio C Hamano

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