Fair critical section (Linux)

Question

On a multi-threaded Linux application I use a mutex for critical sections. This works very well except for the fairness issue. It can happen that a thread leaving a critical

Answer 1

IMHO you can use a FIFO SCHEDULER on Linux and change de priority of threads:

thread_func() {
    ... 
    pthread_t t_id = pthread_self();
    struct sched_param prio_zero, prio_one;
    prio_zero.sched_priority = sched_get_priority_min(SCHED_FIFO);
    prio_one.sched_priority = sched_get_priority_min(SCHED_FIFO) + 1;
    phtread_setschedparam(t_id, SCHED_FIFO, &prio_zero);
    ...
    while(true)
    {
        ... Doing something before
        phtread_setschedparam(t_id, SCHED_FIFO, &prio_one);
        critsect.enter();
        ... do calculations ...
        ... maybe call a blocking operation so we sleep ...
        critsect.leave();
        phtread_setschedparam(t_id, SCHED_FIFO, &prio_zero);
        ... Do something after
    }
}