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

From: Thomas Gleixner
Date: Wed Mar 08 2017 - 04:43:33 EST


On Tue, 7 Mar 2017, Stephane Eranian wrote:
> On Tue, Mar 7, 2017 at 12:04 PM, Luck, Tony <tony.luck@xxxxxxxxx> 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?
> >
> Inside a CAT partition, there may be multiple tasks split into different
> cgroups. We need the ability to monitor groups of tasks individually
> within that CAT partition. I think this is what this bullet is about.

I completely understand that. That's fine and I never debated that one, but
the requirements list is too vague about what you want to measure.

> >>> 5) Put multiple threads into a single measurement group

That can be:

A) threads within a CAT group

B) threads which belong to different CAT groups

A) is fine. B) does not make any sense to me

Same applies for per CPU measurements.