> If you define fairness in this context as not starving other threads > while consuming resources, that is built into the interpreter via > sys.setcheckinterval() and also anywhere the GIL is released for I/O. > What might be interesting is to see if releasing a critical section > and immediately re-acquiring it every _Py_CheckInterval bytecode > operations behaves in a similar manner (see ceval.c, line 869). My > best guess right now is that it will behave as expected when not using > the spin-based critical section. AFAIK, the kernel processes waiters > in a FIFO manner without regard to priority. Because a guarantee of > mutual exclusion is absolutely necessary, it's up to applications to > provide fairness. Python does a decent job of this.
No: fairness in mutex synchronization means that every waiter for the mutex will eventually acquire it; it won't happen that one thread starves waiting for the mutex. This is something that the mutex needs to provide, not the application. Regards, Martin _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
