Just out of curiosity, what version of PHP did you use while profiling?
Going by Special:Version on semantic-mediawiki.org, it says
PHP5.2.0-8+etch13. Is that the version you used?
Looking at the PHP Changelog (http://www.php.net/ChangeLog-5.php), 5.2.0 was
released Nov 2006, and there have been several changes to PCRE (from v6.7 to
7.8 - http://www.pcre.org/changelog.txt ), memleaks plugged and perf tweaks
I realize you're running Debian-etch-stable and Debian has a very
conservative upgrade regimen. But now that you're focusing on squeezing as
much performance from SMW, it may be worthwhile to see how the underlying
PHP version may be influencing performance.
Perhaps, you can then identify the "best" or recommended PHP for us SMW
users. And maybe (cross fingers) the upgraded PCRE in PHP may address some
of the regexp problems you discussed in the past.
joel@... * wireless@...
Think Different! (http://en.wikipedia.org/wiki/Think_different#Text)