Re: [RFC -v2 PATCH 2/3] sched: add yield_to function

Mike Galbraith
2010-12-20T10:46:50Z

On Mon, 2010-12-20 at 12:39 +0200, Avi Kivity wrote:
> On 12/20/2010 12:33 PM, Mike Galbraith wrote:
> > >
> > > Correct. I don't want the other task to run before me, I just don't
> > > want to run before it.
> >
> > OK, so what I gather is that if you can preempt another of your own
> > threads to get the target to cpu, that would be a good thing whether
> > he's on the same cpu as yield_to() caller or not. If the target is
> > sharing a cpu with you, that's even better. Correct?
>
> Correct. I'm not interested in scheduling wrt other tasks, just my tasks.
>
> However, if I'm all alone on my cpu, and the other task is runnable but
> not running, behind some unrelated task, then I do need that task to be
> preempted (or to move tasks around).

So in that case, a pull may be advantageous.

> > Would a kick/hint option be useful?
>
> Depends on what it does...

Let you decide whether you only want to drop a hint and leave it at
that, or also attempt a preemption.

-Mike