From: Linus Torvalds <torvalds@osdl.org>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Nicolas Pitre <nico@cam.org>, Sergey Vlasov <vsu@altlinux.ru>,
Junio C Hamano <junkio@cox.net>,
git@vger.kernel.org
Subject: Re: heads-up: git-index-pack in "next" is broken
Date: Wed, 18 Oct 2006 14:48:43 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0610181434510.3962@g5.osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0610181407040.18885@alien.or.mcafeemobile.com>
On Wed, 18 Oct 2006, Davide Libenzi wrote:
>
> The hash value (hence the hash bucket index) simply directs you to the
> bucket where a real record-compare loop is performed.
As far as I can tell not all loops do a real "record-compare" thing.
Some of the hash loops _only_ look at the hash, and as such a bad hash
will do more than just cause bad performance, it will actually degrade the
diff itself. Isn't that what XDL_MAX_EQLIMIT effectively does?
Btw, the binary delta generator doesn't seem to have this issue at all: it
uses "unsigned int" for the hash values, so the xdiff delta generation
will give the same exact results on 32-bit and 64-bit architectures.
Or was that one of the changes by Nico? (I only looked at the git version
of that code)
Linus
next prev parent reply other threads:[~2006-10-18 21:49 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-17 4:55 heads-up: git-index-pack in "next" is broken Junio C Hamano
2006-10-17 15:39 ` Nicolas Pitre
2006-10-17 16:07 ` Junio C Hamano
2006-10-17 17:00 ` Nicolas Pitre
2006-10-17 18:11 ` Junio C Hamano
2006-10-17 18:47 ` Nicolas Pitre
2006-10-17 19:36 ` Sergey Vlasov
2006-10-17 20:10 ` Junio C Hamano
2006-10-17 20:25 ` Nicolas Pitre
2006-10-17 20:23 ` Nicolas Pitre
2006-10-17 20:51 ` Linus Torvalds
2006-10-17 21:21 ` Nicolas Pitre
2006-10-17 21:46 ` Linus Torvalds
2006-10-18 0:20 ` Nicolas Pitre
2006-10-18 0:57 ` Linus Torvalds
2006-10-18 2:08 ` Nicolas Pitre
2006-10-18 3:12 ` Linus Torvalds
2006-10-18 6:09 ` Davide Libenzi
2006-10-18 14:56 ` Linus Torvalds
2006-10-18 16:17 ` Davide Libenzi
2006-10-18 16:52 ` Linus Torvalds
2006-10-18 21:21 ` Davide Libenzi
2006-10-18 21:48 ` Linus Torvalds [this message]
2006-10-18 22:34 ` Davide Libenzi
2006-10-18 1:30 ` Junio C Hamano
2006-10-18 2:23 ` Nicolas Pitre
2006-10-18 4:16 ` Junio C Hamano
2006-10-18 5:07 ` Junio C Hamano
2006-10-18 10:00 ` Johannes Schindelin
2006-10-18 13:13 ` Nicolas Pitre
2006-10-18 13:02 ` Nicolas Pitre
2006-10-17 21:54 ` Junio C Hamano
2006-10-18 1:38 ` Nicolas Pitre
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