Messages in this thread | | | Date | Tue, 17 Nov 2020 14:43:52 +0000 | From | Mel Gorman <> | Subject | Re: [PATCH 2/3] sched/numa: Allow a floating imbalance between NUMA nodes |
| |
On Tue, Nov 17, 2020 at 03:16:03PM +0100, Peter Zijlstra wrote: > On Tue, Nov 17, 2020 at 01:42:21PM +0000, Mel Gorman wrote: > > This patch revisits the possibility that NUMA nodes can be imbalanced > > until 25% of the CPUs are occupied. The reasoning behind 25% is somewhat > > superficial -- it's half the cores when HT is enabled. At higher > > utilisations, balancing should continue as normal and keep things even > > until scheduler domains are fully busy or over utilised. > > Do we want to make that shift depend on the actual SMT factor?
I considered it but decided against it. I wanted the balance point to be somewhere below SMT because select_idle_sibling tries to avoid SMT sharing so I didn't want a point where SMT sharing caused more problems than memory locality. However, I worried that picking a different imbalance point depending on SMT would be surprising to some.
-- Mel Gorman SUSE Labs
| |