From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Jakub Narebski" <jnareb@gmail.com>,
git@vger.kernel.org, "Ted Ts'o" <tytso@mit.edu>,
"Jonathan Nieder" <jrnieder@gmail.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Clemens Buchacher" <drizzd@aon.at>,
"Eric Wong" <normalperson@yhbt.net>
Subject: Re: [PATCH 2/5] add object-cache infrastructure
Date: Wed, 13 Jul 2011 02:37:01 -0400 [thread overview]
Message-ID: <20110713063701.GA18238@sigill.intra.peff.net> (raw)
In-Reply-To: <7v62n78hpk.fsf@alter.siamese.dyndns.org>
On Tue, Jul 12, 2011 at 11:41:27AM -0700, Junio C Hamano wrote:
> Jeff King <peff@peff.net> writes:
>
> > 2. The disk store uses a binary search over a sorted list of sha1s.
> > Generalizing this to "a sequence of bytes" would not be hard. But
> > we currently have the option of using the uniform distribution of
> > sha1 to make better guesses about our "middle" (see the comments in
> > sha1-lookup.c). That assumption does not hold over arbitrary bytes.
>
> A side note. I notice that the "comment" you refer to appears twice in the
> file, and the sha1_pos() function that comes earlier in the file does not
> protect itself from overshoot penalty like the sha1_entry_pos() function
> does.
>
> Perhaps we should think about unifying them somehow.
It would be easy to implement sha1_entry_pos in terms of sha1_pos by
writing an access function. But it seems unnecessarily slow to add
function call overhead in what should be a fairly tight loop.
OTOH, we do it everywhere else that we call sha1_pos; either it isn't a
big deal, or nobody has bothered to measure and micro-optimize there
yet.
-Peff
next prev parent reply other threads:[~2011-07-13 6:37 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-11 16:13 [RFC/PATCH 0/5] generation numbers for faster traversals Jeff King
2011-07-11 16:16 ` [PATCH 1/5] decorate: allow storing values instead of pointers Jeff King
2011-07-11 16:39 ` Jeff King
2011-07-11 19:06 ` Junio C Hamano
2011-07-11 21:20 ` Jeff King
2011-07-11 16:17 ` [PATCH 2/5] add object-cache infrastructure Jeff King
2011-07-11 16:46 ` Jeff King
2011-07-11 16:58 ` Shawn Pearce
2011-07-11 19:17 ` Junio C Hamano
2011-07-11 22:01 ` Jeff King
2011-07-11 23:21 ` Junio C Hamano
2011-07-11 23:42 ` Junio C Hamano
2011-07-12 0:03 ` Jeff King
2011-07-12 19:38 ` Clemens Buchacher
2011-07-12 19:45 ` Jeff King
2011-07-12 21:07 ` Clemens Buchacher
2011-07-12 21:15 ` Clemens Buchacher
2011-07-12 21:36 ` Jeff King
2011-07-14 8:04 ` Clemens Buchacher
2011-07-14 16:26 ` Illia Bobyr
2011-07-13 1:33 ` John Szakmeister
2011-07-12 0:14 ` Illia Bobyr
2011-07-12 5:35 ` Jeff King
2011-07-12 21:52 ` Illia Bobyr
2011-07-12 6:36 ` Miles Bader
2011-07-12 10:41 ` Jakub Narebski
2011-07-12 17:57 ` Jeff King
2011-07-12 18:41 ` Junio C Hamano
2011-07-13 6:37 ` Jeff King [this message]
2011-07-13 17:49 ` Junio C Hamano
2011-07-11 16:18 ` [PATCH 3/5] commit: add commit_generation function Jeff King
2011-07-11 17:57 ` Clemens Buchacher
2011-07-11 21:10 ` Jeff King
2011-07-11 16:18 ` [PATCH 4/5] pretty: support %G to show the generation number of a commit Jeff King
2011-07-11 16:18 ` [PATCH 5/5] limit "contains" traversals based on commit generation Jeff King
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