------- Additional Comments From law at redhat dot com 2005-04-02 01:31 ------- Some notes on recent poking and prodding.
The big perl speedup is consistent on my P4 -- but perl shows no significant change on my AMD box. Perl spends ~50% of its time in one routine (regexec) and, surprise, that's the routine where profiling shows the great improvements. Unfortunately, the profiling data hasn't pinpointed _why_ that routine is running so much faster. If one is to believe the oprofile data, the huge reduction in cycles actually occurs in the function's header block. But it's not substantially different between the version compiled with and without the threading updates. And it does not appear that threading has turned any of the recursive calls into simple loops. Looking at the profile results from different P4 counters hasn't provided any additional insight yet. Sigh. Anyway, I'll continue poking at Perl -- I'd really like to understand the huge improvements before installing the patch. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19794
