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| -rw-r--r-- | doc/forum/speeding_up_ikiwiki.mdwn | 75 |
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diff --git a/doc/forum/speeding_up_ikiwiki.mdwn b/doc/forum/speeding_up_ikiwiki.mdwn new file mode 100644 index 000000000..c9ccc6fb1 --- /dev/null +++ b/doc/forum/speeding_up_ikiwiki.mdwn @@ -0,0 +1,75 @@ +My website takes a fairly long time to render. It takes a long time to do +things like add pages, too. I'd like to try and understand what takes the +time and what I might be able to do to speed things up. + +I have 1,234 objects on my site (yikes!). 717 are items under "/log" which +I think might be the main culprit because there are some complex pagespecs +operating in that area (e.g. log/YYYY/MM/DD, YYYY/MM and YYYY for YYYY >= +2003, YYYY <= 2008 which include every page under log/ which was modified +in the corresponding YYYY or YYYY/MM or YYYY/MM/DD). There is very little +linking between the world outside of /log and that within it. + +I was interested in generating a graphical representation of ikiwiki's idea of +page inter-dependencies. I started by looking at the '%links' hash using the +following plugin: + + #!/usr/bin/perl + package IkiWiki::Plugin::deps; + + use warnings; + use strict; + use IkiWiki 3.00; + + + sub import { + hook(type => "format", id => "deps", call => \&fooble); + } + + my $hasrun = 0; + + sub fooble ($$) { + if(0 == $hasrun) { + $hasrun = 1; + open MYFILE, ">/home/jon/deps.dot"; + foreach my $key (keys %links) { + my $arrref = $links{$key}; + foreach my $page (@$arrref) { + print MYFILE "$key -> $page;\n"; + } + } + close MYFILE; + } + } + + 1 + +The resulting file was enormous: 2,734! This turns out to be because of the following code in scan() in Render.pm: + + if ($config{discussion}) {$ + # Discussion links are a special case since they're + # not in the text of the page, but on its template. + $links{$page}=[ $page."/".gettext("discussion") ]; + +Worst case (no existing discussion pages) this will double the number of link +relationships. Filtering out all of those, the output drops to 1,657. This +number is still too large to really visualize: the graphviz PNG and PDF output +engines segfault for me, the PS one works but I can't get any PS software to +render it without exploding. + +Now, the relations in the links hash are not the same thing as IkiWiki's notion of dependencies. Can anyone point me at that data structure / where I might be able to add some debugging foo to generate a graph of it? + +Once I've figured out that I might be able to optimize some pagespecs. I +understand pagespecs are essentially translated into sequential perl code. I +might gain some speed if I structure my complex pagespecs so that the tests +which have the best time complexity vs. "pages ruled out" ratio are performed +first. + +I might also be able to find some dependencies which shouldn't be there and +remove the dependency. + +In general any advice people could offer on profiling ikiwiki would be great. +I did wonder about invoking the magic profiling arguments to perl via the CGI +wrapper. + + +-- [[Jon]] |