config: git_config_dump: pre-compile RE for split

It appears the Perl split() operator is not optimized for fixed
strings at all.  With this change, PublicInbox::Config->new (w/o
->fill_all) time is reduced from 1.81s to 1.22s on a config file
with 50K inboxes.

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index cd8957a1276bb0fa01becd74bf47c61158aec127..4d143c6e3cc6620a920ec1ca30b463afe6df5e7d 100644 (file)
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -165,7 +165,7 @@ sub git_config_dump {
        return {} unless -e $file;
        my $cmd = [ qw(git config -z -l --includes), "--file=$file" ];
        my $fh = popen_rd($cmd);
-       my $rv = config_fh_parse($fh, "\0", "\n");
+       my $rv = config_fh_parse($fh, "\0", qr/\n/);
        close $fh or die "failed to close (@$cmd) pipe: $?";
        $rv;
 }