+>>> 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]]
+
+>>>> Git branch `smcv/ka-glob-cache` has Kathryn's patch. Git
+>>>> branch `smcv/memoize-glob2re` does as I suggested, which
+>>>> is less verbose than Kathryn's patch but also not as
+>>>> fast; I'm not sure why, tbh. --[[smcv]]
+
+>>>>> I think it's because my patch focuses on match_glob while the memoize patch focuses on `glob2re`, and `glob2re` is called in `filecheck`, `meta` and `po` as well as in `match_glob` and `match_user`; thus the memoized `glob2re` is dealing with a bigger set of globs to look up, and thus could be just that little bit slower. -- [[KathrynAndersen]]
+
+>>>>>> What may be going on is that glob2re is already a fairly fast
+>>>>>> function, so the overhead of memoizing it with the very generic
+>>>>>> `_memoizer` (see its source) swamps the memoization gain. Note
+>>>>>> that the few functions memoized with the Memoizer before were much
+>>>>>> more expensive, so that little overhead was acceptable then.
+>>>>>>
+>>>>>> It also may be that Kathryn's patch is slightly faster due to using
+>>>>>> the construct `$foo =~ $regexp` rather than `$foo =~ /$regexp/`
+>>>>>> (probably avoids a copy or something like that internally) --
+>>>>>> this despite checking both `exists` and `defined` on the hash, which
+>>>>>> should be reundant AFAICS.
+>>>>>>
+>>>>>> My guess is that the best of both worlds would be to move
+>>>>>> the byhand memoization to glob2re and have it return a compiled
+>>>>>> `/^/i` regexp that can be used without further modifiction in most
+>>>>>> cases. --[[Joey]]
+
+>>>>>>> Done, see `smcv/ready/glob-cache` and `smcv/glob-cache-too-far`.
+>>>>>>>
+>>>>>>> Kathryn's patch is a significant improvement; my first patch on top of
+>>>>>>> that is a trivial cleanup that speeds it up a little, and the next two
+>>>>>>> patches (using precompiled regexes) have surprisingly little effect
+>>>>>>> (they don't slow it down either though, so either omit them or merge
+>>>>>>> them, whichever). Detailed benchmark results below.
+>>>>>>>
+>>>>>>> Moving the memoization to `glob2re` actually seems to slow things down
+>>>>>>> again - I suspect the docwiki has few enough mentions of `user()` etc.
+>>>>>>> that caching them is a waste of time, but perhaps it's not the most
+>>>>>>> representative.
+>>>>>>> --[[smcv]]
+
+[[done]] --[[Joey]]
+
+--------------------------------------------------------------
+
+[[!toggle id="smcv-benchmark" text="current benchmarks"]]
+
+[[!toggleable id="smcv-benchmark" text="""
+master at time of branch:
+
+ time elapsed (wall): 29.6348
+ time running program: 24.9212 (84.09%)
+ time profiling (est.): 4.7136 (15.91%)
+ number of calls: 1360181
+ number of exceptions: 13
+
+ %Time Sec. #calls sec/call F name
+ 13.24 3.2986 3408 0.000968 Text::Balanced::_match_tagged
+ 10.94 2.7253 79514 0.000034 IkiWiki::PageSpec::match_glob
+ 3.19 0.7952 59454 0.000013 <anon>:IkiWiki/Plugin/inline.pm:223
+
+`Improve the speed of match_glob`:
+
+ time elapsed (wall): 27.9755
+ time running program: 23.5293 (84.11%)
+ time profiling (est.): 4.4461 (15.89%)
+ number of calls: 1280875
+ number of exceptions: 13
+
+ %Time Sec. #calls sec/call F name
+ 14.56 3.4257 3408 0.001005 Text::Balanced::_match_tagged
+ 7.82 1.8403 79514 0.000023 IkiWiki::PageSpec::match_glob
+ 3.27 0.7698 59454 0.000013 <anon>:IkiWiki/Plugin/inline.pm:223
+
+`match_glob: streamline glob cache slightly`:
+
+ time elapsed (wall): 27.5753
+ time running program: 23.1714 (84.03%)
+ time profiling (est.): 4.4039 (15.97%)
+ number of calls: 1280875
+ number of exceptions: 13
+
+ %Time Sec. #calls sec/call F name
+ 14.09 3.2637 3408 0.000958 Text::Balanced::_match_tagged
+ 7.74 1.7926 79514 0.000023 IkiWiki::PageSpec::match_glob
+ 3.30 0.7646 59454 0.000013 <anon>:IkiWiki/Plugin/inline.pm:223
+
+`glob2re: return a precompiled, anchored case-insensitiv...`:
+
+ time elapsed (wall): 27.5656
+ time running program: 23.1464 (83.97%)
+ time profiling (est.): 4.4192 (16.03%)
+ number of calls: 1282189
+ number of exceptions: 13
+
+ %Time Sec. #calls sec/call F name
+ 14.21 3.2891 3408 0.000965 Text::Balanced::_match_tagged
+ 7.72 1.7872 79514 0.000022 IkiWiki::PageSpec::match_glob
+ 3.32 0.7678 59454 0.000013 <anon>:IkiWiki/Plugin/inline.pm:223
+
+`make use of precompiled regex objects`:
+
+ time elapsed (wall): 27.5357
+ time running program: 23.1289 (84.00%)
+ time profiling (est.): 4.4068 (16.00%)
+ number of calls: 1281981
+ number of exceptions: 13
+
+ %Time Sec. #calls sec/call F name
+ 14.17 3.2776 3408 0.000962 Text::Balanced::_match_tagged
+ 7.70 1.7814 79514 0.000022 IkiWiki::PageSpec::match_glob
+ 3.35 0.7756 59454 0.000013 <anon>:IkiWiki/Plugin/inline.pm:223
+
+`move memoization from match_glob to glob2re`:
+
+ time elapsed (wall): 28.7677
+ time running program: 23.9473 (83.24%)
+ time profiling (est.): 4.8205 (16.76%)
+ number of calls: 1360181
+ number of exceptions: 13
+
+ %Time Sec. #calls sec/call F name
+ 13.98 3.3469 3408 0.000982 Text::Balanced::_match_tagged
+ 8.85 2.1194 79514 0.000027 IkiWiki::PageSpec::match_glob
+ 3.24 0.7750 59454 0.000013 <anon>:IkiWiki/Plugin/inline.pm:223
+
+--[[smcv]]
+"""]]
+
+--------------------------------------------------------------
+
+[[!toggle id="ka-benchmarks" text="Kathryn's benchmarks"]]
+
+[[!toggleable id="ka-benchmarks" text="""
+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.
+"""]]
+