[RTEMS Project] #2795: Overrun Handling for general real-time models

RTEMS trac trac at rtems.org
Wed Oct 12 06:01:30 UTC 2016

#2795: Overrun Handling for general real-time models
 Reporter:  khchen                               |       Owner:
     Type:  enhancement                          |      Status:  new
 Priority:  high                                 |   Milestone:  4.11.1
Component:  cpukit                               |     Version:  4.11
 Severity:  critical                             |  Resolution:
 Keywords:  Overrun, RMS, SP, Scheduler,         |
  Periodicity                                    |

Comment (by sebastian.huber):

 In RTEMS the behaviour of the rate-monotonic periods depends on the
 scheduler. We have a fix-priority scheduler (default scheduler) and a job-
 level fixed-priority scheduler (EDF).

 In your test case you have 6000/10000 + 1000/2000 = 110% processor
 utilization, so your task set is not schedulable.

 In case of the default scheduler, the priority assignment is not according
 to the rules:


 Task 2 has a shorter period compared to task 1, so it must have a higher

 What changes your patch? You automatically restart the watchdog in case of
 a timeout and count the number of timeouts?

Ticket URL: <http://devel.rtems.org/ticket/2795#comment:2>
RTEMS Project <http://www.rtems.org/>
RTEMS Project

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