Re: [patch] CFS scheduler, -v12

Ingo Molnar
2007-05-22T20:15:36Z

* Chris Friesen <cfriesen@nortel.com> wrote:

> Ingo Molnar wrote:
>
> >CFS is fair even on SMP. Consider for example the worst-case
> >3-tasks-on-2-CPUs workload on a 2-CPU box:
> >
> > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> > 2658 mingo 20 0 1580 248 200 R 67 0.0 0:56.30 loop
> > 2656 mingo 20 0 1580 252 200 R 66 0.0 0:55.55 loop
> > 2657 mingo 20 0 1576 248 200 R 66 0.0 0:55.24 loop
> >
> >66% of CPU time for each task. The 'TIME+' column shows a 2% spread
> >between the slowest and the fastest loop after just 1 minute of runtime
> >(and the spread gets narrower with time).
>
> Is there a way in CFS to tune the amount of time over which the load
> balancer is fair? (Of course there would be some overhead involved.)

it should be fair pretty fast (see the 10 seconds run of massive_intr) -
so it's not 1 minute (if you were worried about that).

Ingo