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V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by bobbyfengb1124 on April 8, 2017

Hi,

I am doing a round robin simulation on my dual core PC running Windows 10. So I am using the windows port. I am trying to create a task1, then in task1, I create a short task task2 with same priority, then I call taskyield() to give up the processor. based on my understanding of the sheduling behaviour, task2 should always run after I call taskyield(), when task2 is completed, task1 will be schedule, if it is in a single processor environment. However, what I experience is that sometimes task2 will be scheduled after taskyield() is called in task1, sometimes task1 will be running again after taskyield() is called.

May I check with you if the simulation version will utilized the dual processors when schedule the tasks with same priority?

Thanks & Regards Feng Bo


V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by richard_damon on April 8, 2017

I would prsume that the Windows simulator will run single (Windows) threaded (and thus single core) as that is the mode that most looks like the processors it runs on natively. What can happen if you have Preemption enable is that if the (simulated) timer tic occurs just after the call to taskyield(), then the taskyield call would switch to task2, and the time tick then switchs control back to task1.


V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by rtel on April 8, 2017

Correct assumption - only a single core is used.

From the OP: >when task2 is completed

What do you mean by completing a task? Does the task delete itself?


V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by bobbyfengb1124 on April 9, 2017

Yes, task 2 will delete itself.


V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by bobbyfengb1124 on April 9, 2017

Thank you Richard, but I think what you are refering to is the TIMESLICING option, right? When I disable TIMESLICING option, when task1 call taskyield(), it will always come back to schedule task1 again.


V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by bobbyfengb1124 on April 9, 2017

V9.0.0 round robin bahaviour simulation on windows 10, dual core PC

Posted by richard_damon on April 10, 2017

Yes, I was thinking of Time Slicing (which requries Preemption)


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