[Python-Dev] Reworking the GIL (original) (raw)

Baptiste Lepilleur baptiste.lepilleur at gmail.com
Sun Nov 8 15:07:22 CET 2009

2009/11/7 Antoine Pitrou <solipsis at pitrou.net>

Hello again, > It shows that, on my platform for this specific benchmark: > * newgil manage to leverage a significant amount of parallelism > (1.7) where python 3.1 does not (3.1 is 80% slower) I think you are mistaken: -j0 (main thread only) newgil: 47.483s, 47.605s, 47.512s -j4 (4 consumer threads, main thread producing/waiting) newgil: 48.428s, 49.217s The runtimes are actually the same, so newgil doesn't leverage anything. However, it doesn't degrade performance like 2.x/3.1 does :-)

Ooops, I was comparing to 3.1 -j4 times which make no sense. One would think I wanted to see that result since I though the GIL was released :/. This greatly reduce the interest of this benchmark...

> * 3.1 is more than 2 times slower than python 2.6 on this > benchmark

That's the most worrying outcome I'd say. Are you sure the benchmark really does the same thing? Under 2.6, you should add re.UNICODE to the regular expression flags so as to match the 3.x semantics.

I've tried, but there is no change in result (the regexp does not use \w & co but specify a lot unicode ranges). All strings are already of unicode type in 2.6.

> [if I understood correctly in 3.x regex release the GIL].

Unless I've missed something it doesn't, no. Hmmm, I was confusing with other modules (bzip2 & hashlib?). Looking back at the result of your benchmark it's obvious. Is there a place where the list of functions releasing the GIL is available? I did not see anything in bz2.compress documentation. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20091108/2c3ea338/attachment.htm>

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