From 3ce7d8bfb822cf253724cc3677e54fad5aeb1e2b Mon Sep 17 00:00:00 2001 From: "http://smcv.pseudorandom.co.uk/" Date: Mon, 3 Mar 2014 07:44:31 -0400 Subject: an order-of-magnitude optimization which also improves correctness --- .../editing_gitbranch_template_is_really_slow.mdwn | 34 ++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'doc') diff --git a/doc/bugs/editing_gitbranch_template_is_really_slow.mdwn b/doc/bugs/editing_gitbranch_template_is_really_slow.mdwn index d8af150c1..57fdbbf4e 100644 --- a/doc/bugs/editing_gitbranch_template_is_really_slow.mdwn +++ b/doc/bugs/editing_gitbranch_template_is_really_slow.mdwn @@ -29,3 +29,37 @@ of the problem is that it evaluates the pagespec `backlink(plugins/goodstuff)` up to a million times, with various pages and locations. --[[smcv]] + +> [[!template id=gitbranch branch=smcv/ready/perf +author="[[Simon McVittie|smcv]]" +browse=http://git.pseudorandom.co.uk/smcv/ikiwiki.git/shortlog/refs/heads/ready/perf]] +> [[!tag patch]] +> +> Previously, if a page like `plugins/trail` contained a conditional like +> +> [[!if test="backlink(plugins/goodstuff)" all=no]] +> +> (which it gets via `templates/gitbranch`), then the +> [[plugins/conditional]] plugin would give `plugins/trail` a dependency on +> `(backlink(plugins/goodstuff)) and plugins/trail`. This dependency is +> useless: that pagespec can never match any page other than +> `plugins/trail`, but if `plugins/trail` has been modified or deleted, +> then it's going to be rendered or deleted *anyway*, so there's no point +> in spending time evaluating match_backlink for it. +> +> Conversely, the influences from the result were not taken into account, +> so `plugins/trail` did not have the +> `{ "plugins/goodstuff" => $DEPEND_LINKS }` dependency that it should. +> +> We should invert that, depending on the influences but not on the test. +> +> This is at least an order of magnitude faster: when I edit the docwiki +> as described above, a refresh takes 37s with nytprof overhead, compared +> with 458s with nytprof overhead before this change. Without nytprof, +> that refresh takes 14s, which is faster than the 24s rebuild again. +> I didn't record how long the refresh took without nytprof before this +> change, but it was something like 200s. +> +> `bestlink` is still the single most expensive function in this refresh +> at ~ 9.5s, with `match_glob` at ~ 5.2s as the runner-up. +> --[[smcv]] -- cgit v1.2.3