[ECOS] Round robin scheduler question

[Ian Gilmour <ian dot gilmour at ffei dot co dot uk>]

I'm having problems with round robin scheduling with the multi-level queue
scheduler so I knocked up a simple test....

I have a system with a monitor task (TaskA).

TaskA creates 2 equal priority tasks (TaskB and TaskC) that simply loop,
each incrementing their own volatile global counter. TaskB and TaskC have
lower priority than TaskA.

Task A also creates another high priority task TaskD. TaskD priority is
lower than TaskA but higher than TaskB and TaskC. TaskD periodically polls
for Control-C input on the monitor. It polls every NNN clock ticks.

TaskA periodically (every couple of secs) dumps the contents of the 2 global
counters until it sees a Control-C flag set by TaskD, at which point it
kills TaskB, TaskC, and TaskD.

I have the multi-level queue scheduler enabled and the scheduler timeslicing
every 5 clock ticks.

If NNN is greater than or equal to 5 TaskB and TaskC round robin schedule as
I expect.

But if NNN is less than 5 TaskC never runs.

Is this the expected behaviour? Or have I inadvertently set something in the
ecos config to get this behaviour?

I expected TaskB and TaskC to get equal time despite neither ever having a
full 5 clock ticks timeslice.

 
cheers,


Ian


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