On 7/11/06, Stefan Westerfeld <[EMAIL PROTECTED]> wrote:
Since we've been comparing different methods here, I thought I might as
well write a benchmark, to look at the performance, too. I wrote a
little test which repeatedly switches between two threads, which wakeup
eachother using a pipe, cond or semaphore.
On an AMD64 3400+ (2200 MHz) running a 2.6.16.16 kernel with preemption
enabled, the timings for 1000000 iterations (each thread runs a brief
period of time 1000000 times) are
- about 5.7 seconds when using a wakeup pipe and poll
- about 5.7 seconds when using a condition with mutex
- about 2.0 seconds when using a semaphore
So: if what you're doing doesn't restrict you in any way, then
semaphores are probably the thing to use.
If you need to wait for multiple things simultaneously (like audio
device fd and another thread), then you can do it with pipes and poll,
but not with semaphores.
Cu... Stefan
--
Stefan Westerfeld, Hamburg/Germany, http://space.twc.de/~stefan
What about POSIX real-time signals? I know mixing threads and signals
is taboo, but I thought I'd throw it out there anyway. Using pselect
then lets you wait atomically for events on file descriptors and/or
signals. Not sure how well it works with threads, though...or if it's
even implemented (though it is described in select(2)).
