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

Dave Robillard drobilla at connect.carleton.ca
Thu Jul 13 16:13:06 UTC 2006

On Wed, 2006-07-12 at 20:54 +0300, Jussi Laako wrote:
> Dave Robillard wrote:
> > realtime thread is pretty sketchy...).  Pipes let you communicate
> > between processes though - I havn't tried the fancier POSIX interprocess
> > stuff yet.
> What do you mean by semaphore then, if not sem_*()?
> sem_post(3)/sem_wait(3) are defined in POSIX realtime extensions (librt
> in glibc). I would recommend _NOT_ to mix these semaphores (or shared
> memory, or message queues) with anything from SysV which is usually
> veeery far from being realtime safe, from implementation point of view.
> IF the implementation happens to be the same in Linux, doesn't mean
> that's the case in any other POSIX system.

Sorry, I /was/ referring to sem_post/sem_wait/etc.  I mean havn't tried
any interprocess posix signalling stuff, like named semaphores or
message queues.

Benchmarking message queues against pipes would be interesting, maybe
Jack could benefit if they're faster?


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