There's an interesting discussion on my weblog at http://taint.org/2006/07/07/184022a.html , regarding the recently-contributed "trie" and Aho-Corasick regexp optimizations, which have been added to perl 5.9.x.
These could provide a way to get *serious* speedups in SpamAssassin. If anyone is interested in working on speedups, this would be a really great place to do it; body rules are by far the biggest CPU time sink in our code. Be sure to read the comments -- the author of the code goes into a lot of detail there! --j.
