underlay: Avoid crashing if lists of underlays (or template directories) are not...

[git.ikiwiki.info.git] / doc / tips / optimising_ikiwiki.mdwn

diff --git a/doc/tips/optimising_ikiwiki.mdwn b/doc/tips/optimising_ikiwiki.mdwn
index e3973733fba4de9754306b80bd22fff8f6a1370b..cf166998bb8060498222768084d2d774e038e173 100644 (file)
--- a/doc/tips/optimising_ikiwiki.mdwn
+++ b/doc/tips/optimising_ikiwiki.mdwn
@@ -34,7 +34,7 @@ when their wiki was small, and found it got slower as they added pages.
 
 ## use the latest version
 
-If your version of ikiwiki is not [[!verison]], try upgrading. New
+If your version of ikiwiki is not [[!version]], try upgrading. New
 optimisations are frequently added to ikiwiki, some of them yielding
 *enormous* speed increases.
 
@@ -140,6 +140,21 @@ That is accomplished as follows:
 Be aware that the [[plugins/search]] plugin has to update the search index
 whenever any page is changed. This can slow things down somewhat.
 
+## profiling
+
+If you have a repeatable change that ikiwiki takes a long time to build,
+and none of the above help, the next thing to consider is profiling
+ikiwiki. 
+
+The best way to do it is:
+
+* Install [[!cpan Devel::NYTProf]]
+* `PERL5OPT=-d:NYTProf`
+* `export PER5OPT`
+* Now run ikiwiki as usual, and it will generate a `nytprof.out` file.
+* Run `nytprofhtml` to generate html files.
+* Those can be examined to see what parts of ikiwiki are being slow.
+
 ## scaling to large numbers of pages
 
 Finally, let's think about how huge number of pages can affect ikiwiki.