Re: [RESEND][PATCH 0/8] Introduce support for artificial Energy Model

[Lukasz Luba]

Hi Rafael,

gentle ping. If you need some help with this maintenance,
we can help.

Regards,
Lukasz

On 4/4/22 13:35, Lukasz Luba wrote:
> Hi Rafael,
>
>
> The patch set has been on LKML for quite a while and got one ACK,
> for the code touching something outside the EM (thermal cooling).
>
> AFAICS there is no interest and objections from others for this code.
>
> Therefore, I have a question:
> What would be be process to have merge this code?
> (We had internally a few reviews of this code)
>
> On 3/21/22 09:57, Lukasz Luba wrote:
> > Hi all,
> >
> > This patch set adds new callback and support for artificial Energy 
> > Model (EM).
> > The new EMs have artificially generated performance states.
> > Such EMs can be created from lean information sources, such
> > as the relative energy efficiency between CPUs. The ACPI based
> > platforms provide this information
> > (ACPI 6.4, s5.2.12.14 'GIC CPU Interface (GICC) Structure'
> > 'Processor Power efficiency Class' field).
> >
> > Artificial EMs might require to directly provide the 'cost' of
> > the generated performance state. This patch set adds a new callback
> > .get_cost() for this. The EM framework does not force any model
> > or formula, it's up to the platform code.
> >
> > Artificial EMs aim to leverage the Energy Aware Scheduler
> > (EAS). Other frameworks relying on performance states
> > information (i.e. IPA/DTPM) must be informed of the
> > EM type and might be prevented from using it. This patch
> > sets also does this by introducing a new flag:
> > EM_PERF_DOMAIN_ARTIFICIAL.
> >
> > The patch set is based on current linux-next, where some
> > changes to OPP & EM are queuing.
> >
> > The patch set also contains (patch 7/8 and patch 8/8) logic which 
> > prevents
> > two EM's client frameworks from using this new EM type. Some other 
> > approach,
> > using 'milli-watts', has been proposed and discussed, but refused [1].
> > This new flag is more precised and should not leave space for
> > wrong interpretation.
> >
> > Shortly after this patch set you will see a patch set implementing the
> > platform code and registering this new EM.
>
>
> No one from Arm is an official maintainer of the EM code.
>
> Regards,
> Lukasz