Real Time (rate monotonic) Scheduling help?

glynn1280 · 11-09-2008, 11:13 AM

Don't know whether anyones familar with rate monotonic and scheduling of real time systems, but here it goes:

Task A (Period = 10 msec, CPU time = 2 msec)
Task B (100, 6)
Task C (250, 11)
Task D (500, 5)
Task E (250, 15)
Task F (100, 6)
Task G (500, 5)
Task H (1000, 20)
Task I (2000, 15)

Question: During the actual operation of the system the driver may press the brake pedal at most 4 times per second. Pressing the pedal turns the system off. This process requires a worst case of 35 msec of cpu time and must respond within 90msec. Explain how you would incorporate this process into the above model.

IS THIS A MATTER OF:- THE 4 TIMES PER SECOND IS THE PERIOD (250msec), BUT IT IS THE DEADLINE OF 35msec THAT THE TASK MUST RESPOND BY SO WE WOULD USE THIS AS THE PERIOD (PERIOD = DEADLINE)?

**koala** · 11-09-2008, 11:38 AM

Please read the forum rules.

Quote:

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glynn1280 · 11-09-2008, 03:22 PM

Ok then, does an aperiodic process still have a period, which is seperate from its hard deadline and can I gather it from the above given information?

11-09-2008, 11:13 AM	#1 (permalink)
glynn1280 Registered User Join Date: Oct 2006 Posts: 8 OS: Vista, Ubuntu	Real Time (rate monotonic) Scheduling help? Don't know whether anyones familar with rate monotonic and scheduling of real time systems, but here it goes: Task A (Period = 10 msec, CPU time = 2 msec) Task B (100, 6) Task C (250, 11) Task D (500, 5) Task E (250, 15) Task F (100, 6) Task G (500, 5) Task H (1000, 20) Task I (2000, 15) Question: During the actual operation of the system the driver may press the brake pedal at most 4 times per second. Pressing the pedal turns the system off. This process requires a worst case of 35 msec of cpu time and must respond within 90msec. Explain how you would incorporate this process into the above model. IS THIS A MATTER OF:- THE 4 TIMES PER SECOND IS THE PERIOD (250msec), BUT IT IS THE DEADLINE OF 35msec THAT THE TASK MUST RESPOND BY SO WE WOULD USE THIS AS THE PERIOD (PERIOD = DEADLINE)?

11-09-2008, 03:22 PM	#3 (permalink)
glynn1280 Registered User Join Date: Oct 2006 Posts: 8 OS: Vista, Ubuntu	Re: Real Time (rate monotonic) Scheduling help? Ok then, does an aperiodic process still have a period, which is seperate from its hard deadline and can I gather it from the above given information?