Re: [PATCH v7 2/2] powerpc: Use cpu_smallcore_sibling_mask at SMT level on bigcores

[Srikar Dronamraju]

* Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx> [2018-08-20 11:11:44]:

> From: "Gautham R. Shenoy" <ego@xxxxxxxxxxxxxxxxxx>
> 
> Each of the SMT4 cores forming a big-core are more or less independent
> units. Thus when multiple tasks are scheduled to run on the fused
> core, we get the best performance when the tasks are spread across the
> pair of SMT4 cores.
> 
> This patch achieves this by setting the SMT level mask to correspond
> to the smallcore sibling mask on big-core systems. This patch also
> ensures that while checked for shared-caches on big-core system, we
> use the smallcore_sibling_mask to compare with the l2_cache_mask.
> This ensure that the CACHE level sched-domain is created, whose groups
> correspond to the threads of the big-core.
> 
> With this patch, the SMT sched-domain with SMT=8,4,2 on big-core
> systems are as follows:


Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>