Re: [patch] git svn slowness on win32

From: Eric Wong <normalperson@yhbt.net>
Date: Feb 17, 2010, 23:15 UTC
Message-ID: <20100217231509.GA29664@dcvr.yhbt.net>
In-Reply-To: <alpine.DEB.1.00.1002161130590.20986@pacific.mpi-cbg.de>

Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

Show 47 quoted lines

> Hi,
> 
> On Tue, 16 Feb 2010, josh robb wrote:
> 
> > I'm using git svn (1.6.4.msysgit.0) within a WindowsXP VM running
> > under VMWare fusion on OSX 10.5. For me (and at least one other person
> > I know) git svn has been unbearably slow.
> > 
> > My profiling shows that almost all of the git-svn runtime is being
> > spent in DynaLoader (via SVN::Base::import) which I guess is slow in a
> > virtualized windows environment. For example:
> > 
> > $ time perl /libexec/git-core/git-svn rebase
> > Current branch master is up to date.
> > 
> > real 2m56.750s
> > user 0m3.129s
> > sys 2m39.232s
> > 
> > I've been able to make significant (an order of magnitude)
> > improvements to it's performance by delaying SVN::Base::import from
> > running until it's actually needed. After making this change:
> > 
> > $ time perl /libexec/git-core/git-svn rebase
> > Current branch master is up to date.
> > 
> > real 0m33.407s
> > user 0m1.409s
> > sys 0m23.054s
> > 
> > git svn rebase -n goes from 3m7.046s to 0m10.312s.
> > 
> > Would love to get some feedback/thoughts etc...
> 
> How about the following commit message (trying to follow 
> http://repo.or.cz/w/git.git?a=blob;f=Documentation/SubmittingPatches;hb=HEAD):
> 
> -- snip --
> git svn: delay importing SVN::Base until it is needed
> 
> Importing functions from a .dll into Git for Windows' perl is pretty slow,
> so let's avoid importing if it is not necessary.
> 
> [... timing statistics here...]
> 
> Signed-off-by: Josh Robb <josh_robb@fastmail.fm>
> -- snap --

Hi Josh,

Your patch was missing a call to ::req_svn() in cmd_branch(), but otherwise it appears fine and passes all tests.

Can you write a proper commit message + patch so we can apply it cleanly as Johannes suggested? Thanks!

(full diff below)

diff --git a/git-svn.perl b/git-svn.perl
index 473a0b9..224c29f 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -36,11 +36,13 @@ $ENV{TZ} = 'UTC';
 $| = 1; # unbuffer STDOUT
 
 sub fatal (@) { print STDERR "@_\n"; exit 1 }
-require SVN::Core; # use()-ing this causes segfaults for me... *shrug*
-require SVN::Ra;
-require SVN::Delta;
-if ($SVN::Core::VERSION lt '1.1.0') {
-	fatal "Need SVN::Core 1.1.0 or better (got $SVN::Core::VERSION)";
+sub _req_svn {
+	require SVN::Core; # use()-ing this causes segfaults for me... *shrug*
+	require SVN::Ra;
+	require SVN::Delta;
+	if ($SVN::Core::VERSION lt '1.1.0') {
+		fatal "Need SVN::Core 1.1.0 or better (got $SVN::Core::VERSION)";
+	}
 }
 my $can_compress = eval { require Compress::Zlib; 1};
 push @Git::SVN::Ra::ISA, 'SVN::Ra';
@@ -730,6 +732,7 @@ sub cmd_branch {
 		$src=~s/^http:/https:/;
 	}
 
+	::_req_svn();
 	my $ctx = SVN::Client->new(
 		auth    => Git::SVN::Ra::_auth_providers(),
 		log_msg => sub {
@@ -4859,6 +4862,8 @@ sub new {
 	$url =~ s!/+$!!;
 	return $RA if ($RA && $RA->{url} eq $url);
 
+	::_req_svn();
+
 	SVN::_Core::svn_config_ensure($config_dir, undef);
 	my ($baton, $callbacks) = SVN::Core::auth_open_helper(_auth_providers);
 	my $config = SVN::Core::config_get_config($config_dir);

-- 
Eric Wong