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

* Gautham R. Shenoy [off-list ref] [2018-08-20 11:11:44]:

From: "Gautham R. Shenoy" <redacted>

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 <redacted>