Balbir Singh [off-list ref] writes:

On 02/03/17 11:49, Oliver O'Halloran wrote:

quoted

In previous generations of Power processors each core had a private L2
cache. The Power9 processor has a slightly different architecture where
the L2 cache is shared among pairs of cores rather than being completely
private.

Making the scheduler aware of this cache sharing allows the scheduler to
make more intelligent migration decisions. When one core in the pair is
overloaded tasks can be migrated to its paired core to improve throughput
without cache-refilling penality typically associated with task
migration.

Could you please describe the changes to sched_domains w.r.t before and
after for P9.

Yes please.

cheers