config: _fill: inbox name extraction optimization

Using substr() instead of a string copy + s// substitution here
reduces ->fill_all from 4.00s to 3.88s with 50K inboxes on my
workstation.

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index 577337dc8a024d375be2db4f72cffb0365be2ffb..cd8957a1276bb0fa01becd74bf47c61158aec127 100644 (file)
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -424,9 +424,7 @@ EOF
                }
        }
 
-       my $name = $pfx;
-       $name =~ s/\Apublicinbox\.//;
-
+       my $name = substr($pfx, length('publicinbox.'));
        if (!valid_inbox_name($name)) {
                warn "invalid inbox name: '$name'\n";
                return;