On Sat, 2007-04-07 at 18:20 +0200, Mike Galbraith wrote:

quoted text
> xx.c
> 
> #include <stdio.h>
> #include <sys/time.h>
> 
> #define max(a,b) ((a) > (b) ? (a) : (b))
> #define min(a,b) ((a) < (b) ? (a) : (b))
> 
> int main(void)
> {
>     struct timeval then, now;
>     struct timespec t = {0, 1000}, r;
> 
>     for(;;) {
>         int t1, t2;
>         short i;
> 
>         if (gettimeofday(&then, 0))
>             break;
>         for (i = 1; i > 0; i++);
>         if (gettimeofday(&now, 0))
>             break;
>         t2 = max(then.tv_usec, now.tv_usec);
>         t1 = min(then.tv_usec, now.tv_usec);
>         if (t2 - t1 >= 1000 && nanosleep(&t, &r))
>             break;
>     }
>     return 0;
> }

I lowered the time to 500us, and ran at nice -10.. it starves tenpercent
here every time.  (ran as taskset -c 1 nice -n -10 ./fairtest)  The
starving 10% duty cycle task has trouble getting 1% CPU.

	-Mike