From: Jeff King <peff@peff.net>
To: git@vger.kernel.org
Cc: "René Scharfe" <l.s.r@web.de>,
"Rasmus Villemoes" <rv@rasmusvillemoes.dk>,
"Eric Sunshine" <sunshine@sunshineco.com>
Subject: Re: [PATCH v2 0/9] address packed-refs speed regressions
Date: Thu, 16 Apr 2015 05:25:19 -0400 [thread overview]
Message-ID: <20150416092518.GA18135@peff.net> (raw)
In-Reply-To: <20150416084733.GA17811@peff.net>
On Thu, Apr 16, 2015 at 04:47:34AM -0400, Jeff King wrote:
> Here's a re-roll incorporating feedback from the list. Thanks everybody
> for your comments. Last time the final number was ~8.5s, which was
> disappointingly slower than v2.0.0. In this iteration, my final numbers
> are:
>
> real 0m5.703s
> user 0m5.276s
> sys 0m0.432s
>
> which is quite pleasing.
I forgot to mention what I _didn't_ include.
We discussed using mmap instead of stdio. Applying René's mmap patch
drops my best-of-five here to 5.114s. Which is nice, but it is a bit
more invasive (and does not help other callers of strbuf_getline).
If I further apply my really nasty patch to avoid the strbuf entirely
(i.e., we parse straight out of the mmap), I can get it down to 4.835s.
I don't know if the complexity is worth it or not. Ultimately, I think
the best route to making packed-refs faster is to drop the whole
ref_cache structure and just iterate directly over the mmap data. It
would use less RAM, and it opens the possibility of binary-searching to
look at only a subset of the entries. That's a _lot_ more invasive,
though.
-Peff
prev parent reply other threads:[~2015-04-16 9:25 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-05 1:06 [PATCH 0/6] address packed-refs speed regressions Jeff King
2015-04-05 1:07 ` [PATCH 1/6] strbuf_getwholeline: use getc macro Jeff King
2015-04-05 1:08 ` [PATCH 2/6] git-compat-util: add fallbacks for unlocked stdio Jeff King
2015-04-05 1:11 ` [PATCH 3/6] strbuf_getwholeline: use getc_unlocked Jeff King
2015-04-05 4:56 ` Jeff King
2015-04-05 5:27 ` Jeff King
2015-04-05 5:35 ` Jeff King
2015-04-05 20:49 ` Junio C Hamano
2015-04-05 14:36 ` Duy Nguyen
2015-04-05 18:24 ` Jeff King
2015-04-05 20:09 ` Junio C Hamano
2015-04-07 13:48 ` Rasmus Villemoes
2015-04-07 19:04 ` Jeff King
2015-04-07 22:43 ` Rasmus Villemoes
2015-04-08 0:17 ` Jeff King
2015-04-05 1:11 ` [PATCH 4/6] strbuf: add an optimized 1-character strbuf_grow Jeff King
2015-04-06 2:13 ` Eric Sunshine
2015-04-06 5:05 ` Jeff King
2015-04-05 1:11 ` [PATCH 5/6] t1430: add another refs-escape test Jeff King
2015-04-05 1:15 ` [PATCH 6/6] refname_is_safe: avoid expensive normalize_path_copy call Jeff King
2015-04-05 13:41 ` [PATCH 0/6] address packed-refs speed regressions René Scharfe
2015-04-05 18:52 ` Jeff King
2015-04-05 18:59 ` Jeff King
2015-04-05 23:04 ` René Scharfe
2015-04-05 22:39 ` René Scharfe
2015-04-06 4:49 ` Jeff King
2015-04-16 8:47 ` [PATCH v2 0/9] " Jeff King
2015-04-16 8:48 ` [PATCH 1/9] strbuf_getwholeline: use getc macro Jeff King
2015-04-16 8:48 ` [PATCH 2/9] git-compat-util: add fallbacks for unlocked stdio Jeff King
2015-04-16 8:49 ` [PATCH 3/9] strbuf_getwholeline: use getc_unlocked Jeff King
2015-04-16 8:51 ` [PATCH 4/9] config: use getc_unlocked when reading from file Jeff King
2015-04-16 8:53 ` [PATCH 5/9] strbuf_addch: avoid calling strbuf_grow Jeff King
2015-04-16 8:58 ` [PATCH 6/9] strbuf_getwholeline: " Jeff King
2015-04-16 9:01 ` [PATCH 7/9] strbuf_getwholeline: use getdelim if it is available Jeff King
2015-04-17 10:16 ` Eric Sunshine
2015-04-21 23:09 ` Jeff King
2015-05-08 23:56 ` Eric Sunshine
2015-05-09 1:09 ` Jeff King
2015-06-02 18:22 ` Eric Sunshine
2015-04-22 18:00 ` Johannes Schindelin
2015-04-22 18:06 ` Jeff King
2015-04-16 9:03 ` [PATCH 8/9] read_packed_refs: avoid double-checking sane refs Jeff King
2015-04-16 9:04 ` [PATCH 9/9] t1430: add another refs-escape test Jeff King
2015-04-16 9:25 ` Jeff King [this message]
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