Re: [RFC PATCH v3 17/17] x86/resctrl: Introduce interface to modify assignment states of the groups

[Moger, Babu]

Hi Peter,

On 4/17/2024 3:56 PM, Peter Newman wrote:
> Hi Babu,
>
> On Wed, Apr 17, 2024 at 12:39 PM Moger, Babu <babu.moger@xxxxxxx> wrote:
> > On 4/17/24 12:45, Peter Newman wrote:
> > > On Thu, Mar 28, 2024 at 6:10 PM Babu Moger <babu.moger@xxxxxxx> wrote:
> > > > diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
> > > > index 2d96565501ab..64ec70637c66 100644
> > > > --- a/Documentation/arch/x86/resctrl.rst
> > > > +++ b/Documentation/arch/x86/resctrl.rst
> > > > @@ -328,6 +328,77 @@ with the following files:
> > > >           None of events are assigned on this mon group. This is a child
> > > >           monitor group of the non default control mon group.
> > > >
> > > > +       Assignment state can be updated by writing to this interface.
> > > > +
> > > > +       NOTE: Assignment on one domain applied on all the domains. User can
> > > > +       pass one valid domain and assignment will be updated on all the
> > > > +       available domains.
> > > How would different assignments to different domains work? If the
> > > allocations are global, then the allocated monitor ID is available to
> > > all domains whether they use it or not.
> > That is correct.
> > [A] Hardware counters(max 2 per group) are allocated at the group level.
> > So, those counters are available to all the domains on that group. I will
> > maintain a bitmap at the domain level. The bitmap will be set on the
> > domains where assignment is applied and IPIs are sent. IPIs will not be
> > sent to other domains.
> Unless the monitor allocation is scoped at the domain level, I don't
> see much point in implementing the per-domain parsing today, as the
> only benefit is avoiding IPIs to domains whose counters you don't plan
> to read.

In that case lets remove the domain specific assignments. We can avoid 
some code complexity.

thanks

Babu