On Thu, Mar 8, 2012 at 3:30 PM, Ronny Meeus <ronny.me...@gmail.com> wrote:
> Hello
>
> I'm are using the xenomai-forge pSOS skin (Mercury).
> My application is running on a P4040 (Freescale PPC with 4 cores).
> Some code snippets are put in this mail but the complete testcode is
> also attached.
>
> I have a test task that just consumes the CPU:
>
> int run_test = 1;
> static void perform_work(u_long counter,u_long b,u_long c,u_long d)
> {
> int i;
> while (run_test) {
> for (i=0;i<100000;i++);
> (*(unsigned long*)counter)++;
> }
> while (1) tm_wkafter(1000);
> }
>
> If I create 2 instances of this task with the T_SLICE option set:
>
> t_create("WORK",10,0,0,0,&tid);
> t_start(tid,T_TSLICE, perform_work, args);
>
>
> I see that only 1 task is consuming CPU.
>
> # taskset 1 ./roundrobin.exe &
> # 0"000.543| [main] SCHED_RT priorities => [1 .. 99]
> 0"000.656| [main] SCHED_RT.99 reserved for IRQ emulation
> 0"000.692| [main] SCHED_RT.98 reserved for scheduler-lock emulation
> 0 -> 6602
> 1 -> 0
>
> If I adapt the code so that I call in my init the threadobj_start_rr
> function, I see that the load is equally distributed over the 2
> threads:
>
> # taskset 1 ./roundrobin.exe &
> # 0"000.557| [main] SCHED_RT priorities => [1 .. 99]
> 0"000.672| [main] SCHED_RT.99 reserved for IRQ emulation
> 0"000.708| [main] SCHED_RT.98 reserved for scheduler-lock emulation
> 0 -> 3290
> 1 -> 3291
>
> Here are the questions:
> - why is the threadobj_start_rr function not called from the context
> of the init of the psos layer.
> - why is the roundrobin implemented in this way? If the tasks would be
> mapped on the SCHED_RR instead of the SCHED_FF the Linux scheduler
> would take care of this.
> On the other hand, once the threadobj_start_rr function is called from
> my init, and I create the tasks in T_NOTSLICE mode, the time-slicing
> is still done.
>
> Thanks.
>
> ---
> Ronny
Any comments on this?
---
Ronny
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