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Re: Query about eCos scheduler


"Ravi Joshi" <ravijoshi@operamail.com> writes:

> Dear all,
> 
> I have following queries on eCos scheduler.
> 
> 1. Which scheduler is being used in eCos(MLQ or bitmap)?

The default is the MLQ scheduler.

> 
> 2. Is there any place to trace this in the kernel?
>

You can turn on instrumentation. This will give you a trace of
important events in the kernel. You have to interpret the contents of
the instrumentation buffer yourself, however.

> 3. I remember reading in eCos reference manual that bitmap scheduler
> doesn't allow multiple threads running on the same priority level,
> what is the effect if user tries to run multiple threads running at
> the same priority level? does any thread starts running?
>

If the application tries to create a thread at a priority that is
already occupied, then it creates it at the next available lower
priority.

> 4. Anybody has clue on what happens if user tries to run multiple
> threads on the same priority with MLQ scheduler?  Which thread will
> get to run first and when will the other threads run? this is
> because all threads have the same priority and scheduler can
> schedule only one thread at a time.
>

The threads will be run in the order in which they were created. If
timeslicing is enabled then the scheduler will switch to the next
thread at each timeslice point.

-- 
Nick Garnett                    eCos Kernel Architect
http://www.ecoscentric.com      The eCos and RedBoot experts


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