Re: allow the load to grow upto its cpu_power (was Re: [Patch] don'tkick ALB in the presence of pinned task)

[Nick Piggin]

Siddha, Suresh B wrote:

> For example, lets take two nodes each having two physical packages. And
> assume that there are two tasks and both of them are on (may or may n't be
> pinned) two packages in node-0
>
> Todays load balance will detect that there is an imbalance between the
> two nodes and will try to distribute the load between the nodes.
>
> In general, we should allow the load of a group to grow upto its cpu_power
> and stop preventing these costly movements.
>
> Appended patch will fix this. I have done limited testing of this patch.
> Guys with big NUMA boxes, please give this patch a try. 
>
> --
>
> When the system is lightly loaded, don't bother about the average load.
> In this case, allow the load of a sched group to grow upto its cpu_power.

Yeah this makes sense. Thanks.

I think we'll only need your first line change to fix this, though.

Your second change will break situations where a single group is very
loaded, but it is in a domain with lots of cpu_power
(total_load <= total_power).

Nick


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