Re: [Contiki-developers] preemptive multitasking

[Kasun H. <kas...@gm...>]

Hi,

As I know preemptive multitasking is supported by Contiki.But I have never
used it. Have look at a platform specific implementation ("mtarch.h"
"mtarch,c") in
http://contiki.git.sourceforge.net/git/gitweb.cgi?p=contiki/contiki;a=tree;f=cpu/msp430;hb=HEAD

On Sun, Nov 13, 2011 at 8:50 PM, Michal Ulianko <mic...@gm...>wrote:

> Yes, I've read that. And I now acknowledge the Contiki is protothread,
> FIFO, event based OS.
>
> But a question remain: What are functions *mtarch_pstart()* and *
> mtarch_pstop()* supposed to mean? They are mentioned in
> http://dak664.github.com/contiki-doxygen/a01626.html and they are
> declared in mt.h.
> They look like either remains of some idea or inception of some idea.
>
>
> 2011/11/13 David Kopf <da...@em...>
>
>> Have you seen http://dak664.github.com/contiki-doxygen/a01625.html? I
>> have
>> not used it and most micros do not have enough RAM for more than one
>> stack.
>> Rtimer interrupts might perhaps give a similar function; look at how
>> contikimac interrupts at 8Hz into a protothread.  One must then make
>> certain
>> that any routines called are reentrant if the interrupt could have
>> occurred
>> in them.
>>
>> -----Original Message-----
>> From: Michal Ulianko
>> Sent: Saturday, November 12, 2011 8:24 PM
>> To: con...@li...
>> Subject: [Contiki-developers] preemptive multitasking
>>
>> Hi,
>>
>> I'm porting Contiki to energymicro efm32g (cortex-m3) platform and I have
>> few questions about preemptive multitasking.
>> There is mention about mtarch_pstart() and mtarch_pstop() functions in the
>> documentation, but they aren't called anywhere. What they should do?
>> Is it really a good idea to allocate stack statically in mtarch_thread?
>> How should I treat stack overflow? (Detecting it with cortex-m3's MPU
>> should
>> not be a problem.)
>>
>> Anyway, how is preemptive multitasking supposed to work with Contiki's
>> protothread-process system? From the example 'multi-threading.c' from the
>> documentation I guess it is intended to put this whole "multitasking" to
>> one
>> protothread-process. And how to implement preemption? My idea is that
>> every
>> time this protothread is run it could run some sort of scheduler, run one
>> task until it yield or some preemption-timer expires, then the protothread
>> itself would yield to let other contiki protothread-processes process some
>> events.
>> Actually I'm really a newbie to Contiki...
>>
>> Regards,
>> Michal Ulianko
>>
>>
>>
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>
>
>
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-- 
Best Regards,
Kasun Hewage