From: Thomas Rast <trast@student.ethz.ch>
To: "René Scharfe" <rene.scharfe@lsrfire.ath.cx>
Cc: Eric Herman <eric@freesa.org>, <git@vger.kernel.org>,
Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH v2 3/3] grep: disable threading in all but worktree case
Date: Mon, 5 Dec 2011 10:02:21 +0100 [thread overview]
Message-ID: <201112051002.22138.trast@student.ethz.ch> (raw)
In-Reply-To: <4ED8F9AE.8030605@lsrfire.ath.cx>
René Scharfe wrote:
> Am 02.12.2011 14:07, schrieb Thomas Rast:
> > Measuring grep performance showed that in all but the worktree case
> > (as opposed to --cached,<committish> or<treeish>), threading
> > actually slows things down. For example, on my dual-core
> > hyperthreaded i7 in a linux-2.6.git at v2.6.37-rc2, I got:
> >
> > Threads worktree case | --cached case
> > --------------------------------------------------------------------------
> > 8 (default) | 2.17user 0.15sys 0:02.20real | 0.11user 0.26sys 0:00.11real
> > 4 | 2.06user 0.17sys 0:02.08real | 0.11user 0.26sys 0:00.12real
> > 2 | 2.02user 0.25sys 0:02.08real | 0.15user 0.37sys 0:00.28real
> > NO_PTHREADS | 1.57user 0.05sys 0:01.64real | 0.09user 0.12sys 0:00.22real
>
> Are the columns mixed up?
Indeed, sorry.
In case you were wondering why this table is different from the
numbers given in the cover letter: I noticed at some point that I had
an incomplete checkout (apparently 'git checkout -- .' is really not
the same as 'git reset --hard'... sigh). Then I saw that while the
numbers were different, the conclusion was not, so I forgot to update
it.
> This is a bit radical. I think the underlying issue that
> read_sha1_file() is not thread-safe can be solved eventually and then
> we'd need to readd that code.
I'm also scared of sha1_file.c, especially when it gets down to
packfiles. But perhaps it wouldn't be *too* hard to do it in parallel
iff the object can be read from the loose object store.
> PS: Patches one and three missed a signoff.
Oops, thanks, turns out I had a misconfigured alias ...
--
Thomas Rast
trast@{inf,student}.ethz.ch
next prev parent reply other threads:[~2011-12-05 9:02 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-25 14:46 [PATCH] grep: load funcname patterns for -W Thomas Rast
2011-11-25 16:32 ` René Scharfe
2011-11-26 12:15 ` [PATCH] grep: enable multi-threading for -p and -W René Scharfe
2011-11-29 9:54 ` Thomas Rast
2011-11-29 13:49 ` René Scharfe
2011-11-29 14:07 ` Thomas Rast
2011-12-02 13:07 ` [PATCH v2 0/3] grep multithreading and scaling Thomas Rast
2011-12-02 13:07 ` [PATCH v2 1/3] grep: load funcname patterns for -W Thomas Rast
2011-12-02 13:07 ` [PATCH v2 2/3] grep: enable threading with -p and -W using lazy attribute lookup Thomas Rast
2011-12-02 13:07 ` [PATCH v2 3/3] grep: disable threading in all but worktree case Thomas Rast
2011-12-02 16:15 ` René Scharfe
2011-12-05 9:02 ` Thomas Rast [this message]
2011-12-06 22:48 ` René Scharfe
2011-12-06 23:01 ` [PATCH 4/2] grep: turn off threading for non-worktree René Scharfe
2011-12-07 4:42 ` Jeff King
2011-12-07 17:11 ` René Scharfe
2011-12-07 18:28 ` Jeff King
2011-12-07 20:11 ` J. Bruce Fields
2011-12-07 20:45 ` Jeff King
2011-12-07 8:12 ` Thomas Rast
2011-12-07 17:00 ` René Scharfe
2011-12-10 13:13 ` Pete Wyckoff
2011-12-12 22:37 ` René Scharfe
2011-12-07 4:24 ` [PATCH v2 3/3] grep: disable threading in all but worktree case Jeff King
2011-12-07 16:52 ` René Scharfe
2011-12-07 18:10 ` Jeff King
2011-12-07 8:11 ` Thomas Rast
2011-12-07 16:54 ` René Scharfe
2011-12-12 21:16 ` [PATCH v3 0/3] grep attributes and multithreading Thomas Rast
2011-12-12 21:16 ` [PATCH v3 1/3] grep: load funcname patterns for -W Thomas Rast
2011-12-12 21:16 ` [PATCH v3 2/3] grep: enable threading with -p and -W using lazy attribute lookup Thomas Rast
2011-12-16 8:22 ` Johannes Sixt
2011-12-16 17:34 ` Junio C Hamano
2011-12-12 21:16 ` [PATCH v3 3/3] grep: disable threading in non-worktree case Thomas Rast
2011-12-12 22:37 ` [PATCH v3 0/3] grep attributes and multithreading René Scharfe
2011-12-12 23:44 ` Junio C Hamano
2011-12-13 8:44 ` Thomas Rast
2011-12-23 22:37 ` [PATCH v2 3/3] grep: disable threading in all but worktree case Ævar Arnfjörð Bjarmason
2011-12-23 22:49 ` Thomas Rast
2011-12-24 1:39 ` Ævar Arnfjörð Bjarmason
2011-12-24 7:07 ` Jeff King
2011-12-24 10:49 ` Nguyen Thai Ngoc Duy
2011-12-24 10:55 ` Nguyen Thai Ngoc Duy
2011-12-24 13:38 ` Jeff King
2011-12-25 3:32 ` Nguyen Thai Ngoc Duy
2011-12-02 17:34 ` [PATCH v2 0/3] grep multithreading and scaling Jeff King
2011-12-05 9:38 ` Thomas Rast
2011-12-05 20:16 ` Thomas Rast
2011-12-06 0:40 ` Jeff King
2011-12-02 20:02 ` Eric Herman
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