From: Pavel Machek <pavel@ucw.cz>
To: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <dsahern@gmail.com>,
git@vger.kernel.org,
Arnaldo Carvalho de Melo <acme@infradead.org>,
linux-kernel@vger.kernel.org, Andrew Vagin <avagin@openvz.org>,
Borislav Petkov <bp@amd64.org>,
David Howells <dhowells@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Paul Mackerras <paulus@samba.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Stephane Eranian <eranian@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
arnaldo.melo@gmail.com,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: Re: 'git describe' is very slow on development trees with lots of commits
Date: Wed, 31 Oct 2012 18:52:26 +0100 [thread overview]
Message-ID: <20121031175226.GB20660@elf.ucw.cz> (raw)
In-Reply-To: <20121027133352.GB30001@gmail.com>
Hi!
> (Cc:-ed the Git development list.)
>
> * David Ahern <dsahern@gmail.com> wrote:
>
> > PERF-VERSION-GEN and specifically the git commands are the
> > cause of more delay than the config checks, especially when
> > doing the build in a VM with the kernel source on an NFS
> > mount.
>
> Yes, I have noticed that too.
....
> The cost on this pretty fast machine is about 1 msecs per commit
> - which adds up to about 2.5 seconds during much of the
> development cycle.
Well... I noticed my builds when little changed are very slow... and
it was due to the computation of version string. Ouch.
pavel@amd:~/mainline-altera/linux$ time git describe
fixes-for-linus-506-g71ca8691
0.68user 0.22system 27.82 (0m27.820s) elapsed 3.26%CPU
pavel@amd:~/mainline-altera/linux$
(Cached it is more reasonable 3 seconds, but it keeps going out of
cache all the time. Uncached clean build is 3 minutes, cached is 9
seconds + time to do git describe).
Thikpad X60.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
prev parent reply other threads:[~2012-10-31 17:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1351261913-28250-1-git-send-email-acme@infradead.org>
[not found] ` <20121026145451.GA14379@gmail.com>
[not found] ` <508AA709.7010202@gmail.com>
2012-10-27 13:33 ` 'git describe' is very slow on development trees with lots of commits Ingo Molnar
2012-10-31 17:52 ` Pavel Machek [this message]
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