RE: [ECOS] scheduler

[Gary Thomas <gthomas@cambridge.redhat.com>]

On 14-May-2001 mekala natarajan wrote:
> Hi,
>    I have a doubt regarding scheduler.
> 
> i have two process one with higher priority and the
> other with lower priority.
> 
> This is the example program which i used.
> 
> 
> int main()
> {
>     xCreateProcess_i(xPclcpsSender_v,5,ZERO,0);
>     xCreateProcess_i(xPclcpr_v,7,ZERO,0);
> 
>         mProcessId_i=xGetProcessId_i();
>       xKillProcess_i(mProcessId_i);
> }
> 
> void xPclcpr_v(void)
> {
>       while(1)
>       {
>       printf("\n Receiver process is created\n");
>       xDelay_v(5);
>       }
> }
> 
> void xPclcpsSender_v(void)
> {
>       while(1)
>       {
>       printf("\n Sender process is created\n");
>       xDelay_v(3);
>       }
> }
> 
> Output:
> -------
>      Sender process is created 
>      Sender process is created
>      receiver process is created
>      Sender process is created
>      Sender process is created
>      receiver process is created
>                ----
> Why is this output. It is supposed to print Sender
> process only once.
> 

Why do you think this should be so?

> How the scheduler behaves here?
> 

I assume that xDelay_v() calls 'thread_sleep()' or some such similar
"blocking" function.

When the "receiver" process is sleeping (xDelay_v()), the "sender"
process will run, thus the printout.

> Can someone explain me?