RTOS timing

[gogoman]

Hi new to this subject, forgive the obvious.

In a multi thread application where thread 1 is called every 30us (highest priority, 3us completion), thread 2 called every 100us,  500us to complete , and thread 3 called  every 1 ms 100us to complete.
A general  explanation would be helpful.

btw The processor clk is 100 mhz,
thanks

[Sal Ammoniac]

Well, thread 2 is a problem because it's getting called every 100us, but it takes 500us to complete. What exactly are you looking for here?

[Brianf]

What overhead does your RTOS have when thread switching?
How much jitter can you tolerate on your thread's start times?

[Kjelt]

Google for "Rate Monotonic Analysis" and study the basics.

[MosherIV]

In a multi thread application where thread 1 is called every 30us (highest priority, 3us completion), thread 2 called every 100us,  500us to complete , and thread 3 called  every 1 ms 100us to complete.
A general  explanation would be helpful.

I do no think that is how RTOS scheduling works.

Generally, RTOS task scheduling is pre-emptive round robin with priorities.
That means every task is given the same length of time slot to run before the next one is scheduled in.
There is a level based priority system, the highest priority tasks get scheduled before the lower ones.
All task run until suspension or completion or they get put back on the suspended task list waiting for their next time slot.

The scheduler in some RTOS can be set to run in co-operative mode, that is tasks run until suspension or completion and then the next task is scheduled.
Again, this can be done with task priorities.

Hope this helps.

[mikerj]

Hi new to this subject, forgive the obvious.

In a multi thread application where thread 1 is called every 30us (highest priority, 3us completion), thread 2 called every 100us,  500us to complete , and thread 3 called  every 1 ms 100us to complete.
A general  explanation would be helpful.

btw The processor clk is 100 mhz,
thanks

You haven't actually asked us a question, what exactly do you want to know?

[gogoman]

thanks for the info.