Subject:
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Re: Spawning threads in NBC
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Newsgroups:
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lugnet.robotics.nxt
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Date:
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Wed, 31 Jan 2007 12:36:00 GMT
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Viewed:
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12907 times
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In lugnet.robotics.nxt, <dickswan@sbcglobal.net> wrote:
>
> I don't know how the NXT-G thread/task scheduler works.
>
> Just wondering if anyone has any idea on the impact on execution
> performance when multiple threads are running? And how often threads are
> scheduled?
>
> For example, if you have a "main" thread running and spawn a secondary
> thread, is the CPU time divided equally between the two threads?
>
> Currently you can't put a thread to "sleep" when you're waiting for a
> timed interval to expire. The low-level code simply loops checking to
> see if interval has expired. Does the firmware detect this situation and
> quickly swap the waiting thread out of execution or does the thread
> consume a "full" timeslice?
I'm sure someone with some firmware knowledge will have a better answer for
this, but my belief is that there are no smarts in the firmware for swapping
threads during a wait - i.e. I bet it uses a full timeslice.
I have done some BT logging from two threads in which I sent the same amount of
information from each and I saw them get equal time (i.e. one would print a line
and then the other would, etc.). However, I don't know how big the timeslices
are.
I would like to see a thread priority scheme and a real "sleep" which will swap
threads immediately. Of course, it's just a toy :).
David
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Message is in Reply To:
 | | RE: Spawning threads in NBC
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| I don't know how the NXT-G thread/task scheduler works. Just wondering if anyone has any idea on the impact on execution performance when multiple threads are running? And how often threads are scheduled? For example, if you have a "main" thread (...) (18 years ago, 31-Jan-07, to lugnet.robotics.nxt)
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