| Subject | Re: [PATCH 16/19] sched/numa: Detect if node actively handling migration | From | Rik van Riel <> | Date | Mon, 04 Jun 2018 16:05:55 -0400 |
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On Mon, 2018-06-04 at 15:30 +0530, Srikar Dronamraju wrote:
> @@ -1554,6 +1562,9 @@ static void task_numa_compare(struct > task_numa_env *env, > if (READ_ONCE(dst_rq->numa_migrate_on)) > return; > > + if (*move && READ_ONCE(pgdat->active_node_migrate)) > + *move = false;
Why not do this check in task_numa_find_cpu?
That way you won't have to pass this in as a pointer, and you also will not have to recalculate NODE_DATA(cpu_to_node(env->dst_cpu)) for every CPU.
> /* > + * If the numa importance is less than SMALLIMP,
^^^ numa improvement
> + * task migration might only result in ping pong > + * of tasks and also hurt performance due to cache > + * misses. > + */ > + if (imp < SMALLIMP || imp <= env->best_imp + SMALLIMP / 2) > + goto unlock;
I can see a use for the first test, but why limit the search for the best score once you are past the threshold?
I don't understand the use for that second test.
What workload benefits from it?
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