Benjamin Franksen
Producer/consumer ping-pong is 15 times slower between threads running on different OS threads than on two unbound threads.
Which OS?
Linux/NPTL. A context switch which changes OS threads involves: setitimer pthread_sigmask pthread_mutex_lock pthread_cond_signal pthread_cond_wait (starting) and in the other thread: pthread_cond_wait (returning) pthread_mutex_unlock pthread_sigmask setitimer setitimer is necessary because I tested that it is installed per thread rather than per process, even though SUSv3 says it should be per process. pthread_sigmask makes the thread holding the capability handle signals. I've heard that the interaction of signals and threads is broken in pre-NPTL Linux threads, I will have to check how it behaves and what should be used in this case (perhaps having signals unblocked in all threads). -- __("< Marcin Kowalczyk \__/ qrczak@knm.org.pl ^^ http://qrnik.knm.org.pl/~qrczak/