1NAME = "Priority inversion tests" 2AUTHOR = "Michal Piotrowski <michal.k.k.piotrowski@gmail.com>" 3TIME = "SHORT" 4TEST_CATEGORY = "FUNCTIONAL" 5TEST_CLASS = "KERNEL" 6TEST_TYPE = "CLIENT" 7DOC = """ 8The basic premise here is to set up a deadlock scenario and confirm that PI 9mutexes resolve the situation. Three worker threads will be created from the 10main thread: low, medium and high priority threads that use SCHED_FIFO as 11their scheduling policy. The low priority thread claims a mutex and then 12starts "working". The medium priority thread starts and preempts the low 13priority thread. Then the high priority thread runs and attempts to claim 14the mutex owned by the low priority thread. Without priority inheritance, 15this will deadlock the program. With priority inheritance, the low priority 16thread receives a priority boost, finishes it's "work" and releases the mutex, 17which allows the high priority thread to run and finish and then the medium 18priority thread finishes. 19 20That's the theory, anyway... 21""" 22 23job.run_test('pi_tests') 24