Hi... On Wed, May 5, 2010 at 17:39, Mohamad Tayssir Alkowatly <idoit.ief@xxxxxxxxx> wrote: > Hi all > > As the long subject indicates, but I'll elaborate the situation: > > I have three pthreads reader/worker/writer. the reader and the writer are of > the same priority and SCHED_FIFO policy while the worker has a lower > priority and a SCHED_RR policy. > The reader is continuously calling select on multiple fds to read from, when > data available it reads and puts them in a reader/worker queue. worker works > then puts the result in a worker/writer queue. writer writes the result to > some fds. > > this program causes a system wide deadlock the moment it started when > running on a uni-processor system. I think this explanation would answer your doubt (from SCHED_SETSCHEDULER(2)) A SCHED_FIFO process runs until either it is blocked by an I/O request, it is preempted by a higher priority process, or it calls sched_yield(2). So, in other word, somehow you make one of these SCHED_FIFO process runs but not blocked sometimes or voluntarily yields its runtime. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
