>I have noticed that ALSA tends to use mutexes a lot >for its internal locking. Has anyone ever considered >using rw-semaphores instead? The biggest impact would >probably be to the /proc filesystem since it would >allow multiple concurrent readers, but I suppose that >it might also reduce other contention issues.
what contention issues? almost all the locks in ALSA are per-device (e.g. per PCM device), so unless you have 2 or more threads accessing the device at the same time, there is no contention. i haven't seen any source code that has such a design, and it would be quite odd given the synchronous nature of audio interfaces. i have seen very, very little locking that happens at the "top level" of ALSA. am i missing them? in addition, its quite a tricky task to work through the code and decide whether a r-lock, w-lock or mutex is needed at any point in time, but i suspect that in most cases, a mutex is called for (i.e. we read and then write the value of a variable). comments? --p _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
