[RTEMS Project] #4019: Potential issue with SMP EDF scheduler and priority inheritance

[RTEMS trac]

#4019: Potential issue with SMP EDF scheduler and priority inheritance
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 Reporter:  Sebastian Huber  |       Owner:  Sebastian Huber
     Type:  defect           |      Status:  assigned
 Priority:  normal           |   Milestone:  6.1
Component:  score            |     Version:
 Severity:  normal           |  Resolution:
 Keywords:                   |  Blocked By:
 Blocking:                   |
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Comment (by Stavros Passas):

 Hi Sebastian,
 I can try to fill in the information for you. the SMP testssuite runs
 clean. We run RTEMS from
 [https://github.com/RTEMS/rtems/commit/714cb06f18ce2c0df265ada06363d71560f14a3e]
 \\

 We run with 2 cores, >= 4 threads (failure is not seen with less than 4
 threads). All threads are pthreads, and are started with
 PTHREAD_EXPLICIT_SCHED If the threads are not pinned to any processor, we
 see no issue. If the threads are pinned to (thread_number % 2), after a
 while (usually 20k-100k iteration) EDF does not schedule any thread --
 both cores are running the idle loop. If I change the schedule to the
 priority affinity SMP scheduler, context switching works as expected.

 I also tried to replace {{{pthread_mutex_lock}}} with {{{sem_wait}}} and
 {{{rtems_semaphore_obtain}}} and all primitives behave the same with EDF.

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Ticket URL: <http://devel.rtems.org/ticket/4019#comment:3>
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