I am both both happy and sorry to say that I solved (happy) the problem, and it was a
pointer error (sorry) in the statement next to the sem_post(s) in your example below.
Of course I did small changes in the code every time I tried to understand the
problem, which gave different error, and ultimately only confused me even more!
I should have learned by now, when I don't understand a thing of what is happening, it
is usually a pointer error.... :-)
So: a very different question: can anyone recommend a tool for statically checking the
correctness of a C program, specifically if all pointers and/or indexes of arrays ar
initialized before use? This would be very useful, apart from adding -Wuninitialized
to CFLAGS...
Cheers!
Jonas
______________________________________________________________________
Jonas Persson E-mail: [EMAIL PROTECTED]
Project Manager, M.Sc C.Sc&E http://www.comsys.se/
Comsys AB Phone: +46-(0)46-286 3051
Forskningsbyn IDEON Fax: +46-(0)46-286 3505
S-223 70 Lund, Sweden
-----Ursprungligt meddelande-----
Fran: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]For Victor
Yodaiken
Skickat: den 29 maj 2001 23:57
Till: [EMAIL PROTECTED]
Amne: Re: [rtl] Weird scheduling problem
What version of RTLinux?
Can you describe the code in more detail?
Try with a simpler design
A:
while(1){
sem_wait(s);
do something
}
B:
while(1){
do something
sem_post(s);
clock_nanosleep(CLOCK_REALTIME, ns2ts(10000));
}
On Tue, May 29, 2001 at 02:27:13PM +0200, Jonas Persson wrote:
> Hi all,
>
> I have a strange scheduling problem. Let's say I have two (RTL-) threads, A and B,
>which interact in the following way - B, which has higher priority, calls sem_wait on
>a semaphore. Whenever A has one piece of data ready for B, A calls sem_post on the
>same semaphore.
>
> For whatever reason, when running this example A runs one cycle and so does B. But
>when I insert another module, being another RTLinux program, whenever usleep() is
>called from there, both A and B runs another cycle!
>
> Both A and B are periodic processes with the same periodicity, but only A make calls
>to pthread_make_periodic_np and pthread_wait_np since B waits for the semaphore and
>has higher priority than A.
>
> Any thought appreciated!
>
> Regards,
> Jonas
>
> ______________________________________________________________________
> Jonas Persson E-mail: [EMAIL PROTECTED]
> Project Manager, M.Sc C.Sc&E http://www.comsys.se/
> Comsys AB Phone: +46-(0)46-286 3051
> Forskningsbyn IDEON Fax: +46-(0)46-286 3505
> S-223 70 Lund, Sweden
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