Andy Ibbotson wrote:
> When running from the "Live CD" I can set the base period to 17000ns anything 
> less generates RTAPI delays - is this in keeping with the jitter values?
>   
The jitter is only part of the story.  When you put tasks in the base 
thread, they have to finish executing within that
thread time.  Unfortunately, it is not very easy to find out how long 
each particular task takes to run on any
specific CPU.  There are statistics that rtapi takes, however, and so 
you can check the statistics on all the
tasks in your base thread and add them up.  You then need to leave a 
good cushion to cover cache flushes and
other things that slow the CPU down from time to time.  While 4 - 6 us 
jitter is QUITE good, that is just the
scheduling jitter, ir tells you very little about how much the tasks 
need.  If your base thread tasks take 15 us
to complete, then clearly adding 4 - 6 us jitter, you will have trouble 
with a 17 us base period.

Jon

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