Re: [PATCH 10/10] sched/fair: Implement an EEVDF like policy

[Peter Zijlstra]

On Thu, Mar 09, 2023 at 10:06:33AM +0100, Peter Zijlstra wrote:
> Hi Mike!
> 
> On Wed, Mar 08, 2023 at 02:36:01PM +0100, Mike Galbraith wrote:
> > On Wed, 2023-03-08 at 09:39 +0100, Mike Galbraith wrote:
> > >
> > > Curiosity got the best of me...
> > 
> > Remember this little bugger, allegedly distilled from a real
> > application control thread starvation issue?
> 
> Oooh, yeah, I should still have that somewhere. I'll try and remember
> what exactly was needed to make it behave properly.

That thing wants both wakeup preemption and sleeper bonus. Specifically,
it needs the signal to insta-preempt the 'pointless' kill loop.

What happens is that while positive lag, we get this, when negative lag
happens wakeup-preemption is not achieved and we get delayed by a full
tick.

This gets us very little actual runtime.

Let me see what do do about that...