diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/todo/should_optimise_pagespecs.mdwn | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/doc/todo/should_optimise_pagespecs.mdwn b/doc/todo/should_optimise_pagespecs.mdwn index 3dfa8e1f2..f3048f328 100644 --- a/doc/todo/should_optimise_pagespecs.mdwn +++ b/doc/todo/should_optimise_pagespecs.mdwn @@ -235,6 +235,21 @@ master at the time of rebasing: 14.20s to rebuild, 10.04/12.07/14.01s to refresh. I think you can see the bug clearly here - the pagespecs are getting more complicated every time! +> I can totally see a bug here, and it's one I didn't think existed. Ie, +> I thought that after the first refresh, the pagespec should stabalize, +> and what it stabalized to was probably unnecessarily long, but not +> growing w/o bounds! +> +> a) Explains why ikiwiki.info has been so slow lately. Well that and some +> other things that overloaded the system. +> b) Suggests to me we will probably want to force a rebuild on upgrade +> when fixing this (via the mechanism in the postinst). +> +> BTW, the underlying bug here is really horribly simple: +> When refreshing, `loadindex` preserves the previous depends list, +> and `add_depends` adds stuff to it. So it doubles every time a page is +> re-rendered during refresh. --[[Joey]] + After the initial optimization: 14.27s to rebuild, 8.26/8.33/8.26 to refresh. Success! @@ -243,17 +258,44 @@ I'm worried that duplicates will just build up (again) in less simple cases, though, so 0.2s is probably a small price to pay for that not happening (it might well be experimental error, for that matter). +> It's weird that the suggested optimisations to +> `add_depends` had no effect. So, the commit message to +> b6fcb1cb0ef27e5a63184440675d465fad652acf is actually wrong.. ? --[[Joey]] + Not saving {depends} to the index, using a hash instead of a list to de-duplicate, and allowing add_depends to take an arrayref instead of a single pagespec had no noticable positive or negative effect on this test. +> I see e4cd168ebedd95585290c97ff42234344bfed46c is still in your branch +> though. I don't like using an arrayref, it could just take `($page, @depends)`. +> and I don't see the need to keep it if it doesn't currently help. +> +> Is there any reason to keep 7227c2debfeef94b35f7d81f42900aa01820caa3 +> if it doesn't improve speed? +> --[[Joey]] + Memoizing the results of pagename brought the rebuild time down to 14.06s and the refresh time down to 7.96/7.92/7.92, a significant win. +> Ok, that seems safe to memoize. (It's a real function and it isn't +> called with a great many inputs.) Why did you chose to memoize it +> explicitly rather than adding it to the memoize list at the top? + Refactoring to use pagespec_match_list looks more risky from a code churn point of view; rebuild now takes 14.35s, but refresh is only 7.30/7.29/7.28, another significant win. --[[smcv]] +> I had mostly convinced myself that +> `pagespec_match_list` would not lead to a speed gain here. My reasoning +> was that you want to stop after finding one match, while `pagespec_match_list` +> checks all pages for matches. So what we're seeing is that +> on a rebuild, `@changed` is all pages, and not short-circuiting leads +> to unnecessary work. OTOH, on refresh, `@changed` is small and I suppose +> `pagespec_match_list`'s other slight efficiencies win out somehow. +> +> Welcome to the "I made ikiwiki twice as fast +> and all I got was this lousy git sha1sum" club BTW :-) --[[Joey]] + [[!tag wishlist patch patch/core]] |