Re: [PATCH] sched/numa: Restore sched feature NUMA to its earlier avatar.

From: Ingo Molnar
Date: Wed Jul 08 2015 - 09:56:54 EST



* Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> wrote:

> In commit:8a9e62a "sched/numa: Prefer NUMA hotness over cache hotness"
> sched feature NUMA was always set to true. However this sched feature was
> suppose to be enabled on NUMA boxes only thro set_numabalancing_state().
>
> To get back to the above behaviour, bring back NUMA_FAVOUR_HIGHER feature.

Three typos and a non-standard commit ID reference.

> /*
> + * NUMA_FAVOUR_HIGHER will favor moving tasks towards nodes where a
> + * higher number of hinting faults are recorded during active load
> + * balancing. It will resist moving tasks towards nodes where a lower
> + * number of hinting faults have been recorded.
> */
> -SCHED_FEAT(NUMA, true)
> +SCHED_FEAT(NUMA_FAVOUR_HIGHER, true)
> #endif
>

So the comment spells 'favor' American, the constant you introduce is British
spelling via 'FAVOUR'? Please use it consistently!

Also, this name is totally non-intuitive.

Make it something like NUMA_FAVOR_BUSY_NODES or so?

Also, I'm wondering how this can schedule in a stable fashion: if a non-busy node
is not favored, how can we end up there to start building up hinting faults?

Thanks,

Ingo
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