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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201112051002.22138.trast@student.ethz.ch \
--to=trast@student.ethz.ch \
--cc=eric@freesa.org \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=rene.scharfe@lsrfire.ath.cx \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.