Re: [sched/fair] fcf0553db6: netperf.Throughput_Mbps -30.8% regression

From: Vincent Guittot
Date: Mon Oct 05 2020 - 03:12:52 EST


On Mon, 5 Oct 2020 at 08:50, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Sun, Oct 04, 2020 at 09:27:16PM +0800, kernel test robot wrote:
> > Greeting,
> >
> > FYI, we noticed a -30.8% regression of netperf.Throughput_Mbps due to commit:
> >
> >
> > commit: fcf0553db6f4c79387864f6e4ab4a891601f395e ("sched/fair: Remove meaningless imbalance calculation")
>
> This is the middle of a series that reworks the load balancer. Does this
> regression still exist at the end of it?
>
> Which would be around:
>
> 57abff067a08 ("sched/fair: Rework find_idlest_group()")
>
> or possible a little later, Vincent?

I would consider 6cf82d559e1a ("sched/cfs: fix spurious active migration")

But even then, some fixes have been added. Mel perfectly described that