Re: [PATCH 1/2] sched/fair: Consider SD_NUMA when selecting the most idle group to schedule on

From: Peter Zijlstra
Date: Tue Feb 13 2018 - 08:04:57 EST


On Tue, Feb 13, 2018 at 11:35:48AM +0000, Mel Gorman wrote:
> > However, if we have numa balancing enabled, that will counteract
> > the normal spreading across nodes, so in that regard it makes sense, but
> > the above code is not conditional on numa balancing.
> >
>
> It's not conditional on NUMA balancing because one case where it mattered
> was a fork-intensive workload driven by shell scripts. In that case, the
> workload benefits from preferring a local node without any involvement from
> NUMA balancing. I could make it conditional on it but it's not strictly
> related to automatic NUMA balancing, it's about being less eager about
> starting new children on remote nodes.

Yeah, I suppose. And you're right, there's no real winning this. It's
all tea-leaves and entrails.

In any case, I think I prefer the kill sync early variant and you were
going to ammend some comments. Can you respin and resend all these
patches (can do in a single series)?