#136 Periodic thread isBestEffort

[Pharos Team]

In some cases, the periodic thread does not meet the period. That is, a job of a thread may take longer than its period. The current Pharos behavior is to trigger a health handler (even if the thread does not have a deadline).

In this ticket it is proposed for periodic threads to have a "isBestEffort" boolean flag which, if set to TRUE (the default is FALSE), the health handler will not be invoked and the thread will just be rescheduled to awake at the next release instant (release + N*period)

[Pharos Team]

Implemented in threadperiodic.c:

/* if is not a best error */
            if(periodic->isBestEffort == FALSE)
            {
                /* announce error (a full period elapsed and the thread did not even start to execute) */
                pharosSThreadErrorAnnounce(thread , PHAROS_THREAD_ERROR_PERIOD_MISS , NULL , NULL);
            }
            else
            {
                /* awake at the next release instant */
                thread->lastReplenishmentInstant = thread->lastReplenishmentInstant +
                        ((currentTime - thread->lastReplenishmentInstant) / thread->replenishBudgetInterval + 1) * thread->lastReplenishmentInstant;

                pharosITimeTickAddThread(&periodic->rtThread.thread , thread->lastReplenishmentInstant ,
                                         PHAROS_TIME_TICK_AWAKEN_PERIODIC_THREAD , thread->scheduler);

                /* re-enable interrupts */
                pharosCpuEnableInterrupts(&interrupt);

                break;
            }

Tested in Test3200.