Subject:
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Re: LeJos threads / sleep() takes too long
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Newsgroups:
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lugnet.robotics.rcx.java
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Date:
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Wed, 6 Mar 2002 16:06:43 GMT
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Viewed:
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3767 times
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Hi Bart,
Bart Pattyn <rcx@ranavision.com> writes:
>
> I have the impression my "try { sleep(nnn) }" takes
> a somewhat arbitrary time. It's 'at least' nnn milisec,
> but often much longer (particularly when sensorthread
> has a lot of work, it seems).
if you mean LISTENER_THREAD then that sounds plausible.
> Is this 'standard' Java behaviour?
Yes, LISTENER_THREAD has maximum priority, so it runs before
any threads of lower priority, even yield doesn't help.
> It becomes very difficult to have a timed 'small
> turn left' routine. Sometimes it turns a bit (as I want),
> sometimes it makes a 180°. And no, I can't miss a rotation
> sensor on this one (already 'overloading' sensors with light+touch etc)
Yes, I think we'll have to fix that somehow.
> It seems a bit akward to go about and "implement" a
> low-level sleep?! ( slicing sleep into 10ms and verify
> system clock?)
That won't help you, if your thread doesn't run.
> Is thread-priority the problem here? (not clear if
> higest-priority threads really 'yields()')
I think the problem is that the sensor thread has maximum priority
and too much work to do, so it blocks other threads.
> Any suggestions?
Play with Poll.setThrottle.
Have fun
Jürgen
--
Jürgen Stuber <stuber@loria.fr>
http://www.loria.fr/~stuber/
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Message has 1 Reply:
 | | Re: LeJos threads / sleep() takes too long
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| The priority mechanism used in lejos is the same as that specified in the Real Time Specification for Java (RTSJ): Threads of a higher priority will absolutely block threads of a lower priority as long as they remain runnable. The sensor listener (...) (23 years ago, 1-Apr-02, to lugnet.robotics.rcx.java)
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Message is in Reply To:
| | LeJos threads / sleep() takes too long
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| Experimenting with Lejos, two 'major' problems: memory (cleaning up platform & lang: Math.class is huge!) and... threads. I have the impression my "try { sleep(nnn) }" takes a somewhat arbitrary time. It's 'at least' nnn milisec, but often much (...) (23 years ago, 6-Mar-02, to lugnet.robotics.rcx.java)
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