[Lmuse-developer] MusE 0.7.1pre1 scheduling priority bug

[Levi D. B. <ld...@pu...>]

On Sunday 28 November 2004 4:15 pm, Robert Jonsson wrote:

>       * Made some changes to how threads are created, for systems
>         where thread creation has been erratic, linux2.6 in various
>         configurations.

On my kernel 2.4.26 system, I get the following on startup:

set realtime scheduler: Invalid argument
midi thread 26436 _NOT_ running SCHED_FIFO

In muse/midiseq.cpp, when it attempts to change the scheduling priority, it 
tries setting it to 0.  This I think is the problem.  I manually set it to 1, 
and it appears to have successfully set the scheduling priority/policy.  Then 
I found something a little better (but still seems a bit odd setting it as 
low as possible...)

void MidiSeq::threadStart(void*)
      {
      struct sched_param rt_param;
      memset(&rt_param, 0, sizeof(rt_param));

      if (prio == 0) prio = sched_get_priority_min(SCHED_FIFO);

      printf("scheduling priority set to %d\n", prio);

      rt_param.sched_priority = prio;

      int rv = pthread_setschedparam(pthread_self(), SCHED_FIFO, &rt_param);
      if (rv != 0)
            perror("set realtime scheduler");

      int policy;
      if ((policy = sched_getscheduler (0)) < 0) {
            printf("Cannot get current client scheduler: %s\n", 
strerror(errno));
            }
      if (policy != SCHED_FIFO)
            printf("midi thread %d _NOT_ running SCHED_FIFO\n", getpid());
      updatePollFd();
      }

Notice the call to sched_get_priority_min(SCHED_FIFO).

This is the output when I run muse now:

[root@x1-6-00-a0-cc-e5-08-b1 muse]# ./muse
DEBUG: connecting to `default' server
no locale <muse_en_US>/</usr/share/muse/locale>
scheduling priority set to 1

So, it appears to not like the priority of 0.

-- 
Levi D. Burton
http://www.puresimplicity.net/~ldb/