[linux-audio-dev] realtimeness: pthread_cond_signal vs. pipe write

[Paul Davis]

On Wed, 2006-06-07 at 11:12 +0300, Jussi Laako wrote:
> Paul Davis wrote:
> > writing to a pipe is not 100% RT safe, but if the pipe is created in a
> > shm filesystem, its as close to it as you will get without ... 
> 
> Nowadays, there's also available a very good interface from POSIX RT
> extensions; posix message queues. See mq_send(3). You can use either
> mq_receive(3) or mq_notify(3) for reception of the message.
> 
> I also measured posix message queues to be about twice as fast as for
> example local (unix) sockets.
> 
> Now that Linux systems generally are pretty close to full POSIX
> (IEEE-1003.1) compliance, I don't see any reason why not to make
> advantage of it.

nice to hear that they are faster. on the other hand, once again POSIX
screws us all over by not integrating everything into a single blocking
wait call. i've said it before, i'll say it again - this is one of the
few things that the win32 API gets right - you can block in one call on
almost *anything*. AFAICT, you cannot select/poll on a msg queue.