Re: git slow unless piped to cat

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Date: Aug 27, 2019, 08:56 UTC
Message-ID: <20190827085637.g6cpnuofpteyfqfz@pengutronix.de>
In-Reply-To: <20190827084111.GU20404@szeder.dev>

On Tue, Aug 27, 2019 at 10:41:11AM +0200, SZEDER Gábor wrote:

Show 26 quoted lines

> On Tue, Aug 27, 2019 at 10:15:59AM +0200, Uwe Kleine-König wrote:
> > I have a problem here with git being slow in some situations.
> > Using git 2.23.0 (from Debian) the effect is:
> > 
> > ukl@dude.ptx:/ptx/src/git/linux.git$ sudo sh -c "echo 3 > /proc/sys/vm/drop_caches"; time git show v5.2
> > tag v5.2
> > ...
> > 
> > real	0m12.727s
> > user	0m0.300s
> > sys	0m0.371s
> > 
> > But to get the actual data isn't the problem:
> > 
> > ukl@dude.ptx:/ptx/src/git/linux.git$ sudo sh -c "echo 3 > /proc/sys/vm/drop_caches"; time git show v5.2 | cat
> > tag v5.2
> > ...
> > 
> > real	0m0.764s
> > user	0m0.014s
> > sys	0m0.020s
> > 
> 
> How does 'git --no-pager show v5.2' perform?  If it's as fast as the
> case piping the output to cat, then look into what pager and pager
> options you use.

	ukl@dude.ptx:/ptx/src/git/linux.git$ sudo sh -c "echo 3 > /proc/sys/vm/drop_caches"; time git --no-pager show v5.2
	tag v5.2
	...

	real	0m13.225s
	user	0m0.355s
	sys	0m0.336s

So this doesn't seem to be the problem. Also the local configuration can be ruled out:

	ukl@dude.ptx:/ptx/src/git/linux.git$ sudo sh -c "echo 3 > /proc/sys/vm/drop_caches"; time env GIT_CONFIG_NOSYSTEM=1 HOME=/nonexistant XDG_CONFIG_HOME=/nonexistant git --no-pager show --no-color v5.2
	tag v5.2
	...

	real	0m13.587s
	user	0m0.335s
	sys	0m0.336s

Thanks Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |