Re: [PATCH 09/10] sched/fair: disable stealing if too many NUMA nodes

From: Peter Zijlstra
Date: Mon Oct 22 2018 - 13:06:53 EST

On Mon, Oct 22, 2018 at 07:59:40AM -0700, Steve Sistare wrote:
> The STEAL feature causes regressions on hackbench on larger NUMA systems,
> so disable it on systems with more than sched_steal_node_limit nodes
> (default 2).

How come? From a quick read the stealing is per LLC, where do we steal
across nodes?