David Beazley <d...@dabeaz.com> added the comment: I've attached a test "fair.py" that gives an example of the fair CPU scheduling issue. In this test, there are two threads, one of which has fast-running ticks, one of which has slow-running ticks.
Here is their sequential performance (OS-X, Python 2.6): slow: 5.71 fast: 0.32 Here is their threaded performance (OS-X, Python 2.6.4): slow : 5.99 fast : 6.04 (Notice : Huge jump in execution, unfair CPU) Here is their threaded performance using the Py3K New GIL: slow : 5.96 fast : 0.67 (Notice : Fair CPU use--time only doubled) Using Linux with semaphores gives no benefit here. The fast code is stalled in the same way. For example: here are my Linux results (Ubuntu 8.10, Python-2.6.4, dual-core, using semaphores): Sequential: slow : 6.24 fast : 0.59 Threaded: slow : 6.40 fast : 6.69 (even slower than the slow code!) ---------- Added file: http://bugs.python.org/file16946/fair.py _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue8299> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com