ikiwiki/doc/todo/Improving_the_efficiency_of...

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I've been profiling my IkiWiki to try to improve speed (with many pages makes speed even more important) and I've written a patch to improve the speed of match_glob. This matcher is a good one to improve the speed of, because it gets called so many times.
Here's my patch - please consider it! -- [[KathrynAndersen]]
> It seems to me as though changing `glob2re` to return qr/$re/, and calling
> `memoize(glob2re)` next to the other memoize calls, would be a less
> verbose way to do this? --[[smcv]]
>> I think so, yeah. Anyway, do you have any benchmark results handy,
>> Kathryn? --[[Joey]]
>>> See below.
>>> Also, would it make more sense for glob2re to return qr/^$re$/i rather than qr/$re/? Everything that uses glob2re seems to use
$foo =~ /^$re$/i
>>> rather than /$re/ so I think that would make sense.
>>> -- [[KathrynAndersen]]
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Benchmarks done with Devel::Profile on the same testbed IkiWiki setup. I'm just showing the start of the profile output, since that's what's relevant.
Before:
<pre>
time elapsed (wall): 27.4173
time running program: 22.5909 (82.40%)
time profiling (est.): 4.8264 (17.60%)
number of calls: 1314729
number of exceptions: 65
%Time Sec. #calls sec/call F name
11.05 2.4969 62333 0.000040 IkiWiki::PageSpec::match_glob
4.10 0.9261 679 0.001364 Text::Balanced::_match_tagged
2.72 0.6139 59812 0.000010 IkiWiki::SuccessReason::merge_influences
</pre>
After:
<pre>
time elapsed (wall): 26.1843
time running program: 21.5673 (82.37%)
time profiling (est.): 4.6170 (17.63%)
number of calls: 1252433
number of exceptions: 65
%Time Sec. #calls sec/call F name
7.66 1.6521 62333 0.000027 IkiWiki::PageSpec::match_glob
4.33 0.9336 679 0.001375 Text::Balanced::_match_tagged
2.81 0.6057 59812 0.000010 IkiWiki::SuccessReason::merge_influences
</pre>
Note that the seconds per call for match_glob in the "after" case has gone down by about a third.
K.A.
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<pre>
diff --git a/IkiWiki.pm b/IkiWiki.pm
index 08a3d78..c187b98 100644
--- a/IkiWiki.pm
+++ b/IkiWiki.pm
@@ -2482,6 +2482,8 @@ sub derel ($$) {
return $path;
}
+my %glob_cache;
+
sub match_glob ($$;@) {
my $page=shift;
my $glob=shift;
@@ -2489,8 +2491,15 @@ sub match_glob ($$;@) {
$glob=derel($glob, $params{location});
- my $regexp=IkiWiki::glob2re($glob);
- if ($page=~/^$regexp$/i) {
+ # Instead of converting the glob to a regex every time,
+ # cache the compiled regex to save time.
+ if (!exists $glob_cache{$glob}
+ or !defined $glob_cache{$glob})
+ {
+ my $re=IkiWiki::glob2re($glob);
+ $glob_cache{$glob} = qr/^$re$/i;
+ }
+ if ($page =~ $glob_cache{$glob}) {
if (! IkiWiki::isinternal($page) || $params{internal}) {
return IkiWiki::SuccessReason->new("$glob matches $page");
}
</pre>
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