RE: [PATCH 1/1] x86/cqm: Cqm requirements

[Thomas Gleixner]

On Tue, 7 Mar 2017, Luck, Tony wrote:

> > That's all nice and good, but I still have no coherent explanation why
> > measuring across allocation domains makes sense.
> 
> Is this in reaction to this one?
> 
> >> 5)      Put multiple threads into a single measurement group
> 
> If we fix it to say "threads from the same CAT group" does it fix things?
> 
> We'd like to have measurement groups use a single RMID ... if we
> allowed tasks from different CAT groups in the same measurement
> group we wouldn't be able to split the numbers back to report the
> right overall total for each of the CAT groups.

Right. And the same applies to CPU measurements. If we have threads from 3
CAT groups running on a CPU then the aggregate value (except for bandwidth
which can be computed by software) is useless.

Thanks,

	tglx