Re: [Xen-devel] [RFC PATCH 0/7] Intel Cache Monitoring: Current Status and Future Opportunities

[Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>]

On Wed, Apr 08, 2015 at 08:23:11AM +0000, Dario Faggioli wrote:
> On Wed, 2015-04-08 at 13:59 +0800, Chao Peng wrote:
> 
> > > Mostly, I was curious to learn why that is not reflected in the current
> > > implementation, i.e., whether there are any reasons why we should not
> > > take advantage of per-socketness of RMIDs, as reported by SDM, as that
> > > can greatly help mitigating RMID shortage in the per-CPU/core/socket
> > > configuration (in general, actually, but it's per-cpu that I'm
> > > interested in).
> > 
> > Andrew is right, RMID is a per-socket property. One reason it's not used
> > in current implementation, I think, is the fact that max_rmid is
> > normally the same among sockets, though they can be different in theory.
> > So the same RMID is targeted for all the sockets. But per-socketness of
> > RMIDs can be used anyway. 
> > 
> Yeah, but rather than to the maximum number of available RMIDs, what I'm
> much interested in is whether I can use _the_ _same_ RMID for different
> cores, if they belong to different sockets. AFAIUI, it is possible, is
> that correct?

You are correct. So you actually have 72 RMIDs(0~71) for each sockets.
Normally there are 2 or more RMIDs per hardware thread.

Chao

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