Re: [EXTERNAL] Re: [PATCH v4 1/3] perf: marvell: Add MPAM partid filtering to CN10K TAD PMU

[Will Deacon <will@kernel.org>]

On Fri, Jun 26, 2026 at 09:57:44AM +0100, Ben Horgan wrote:
> >> Where is the user expected to get the PARTID from? The MPAM driver
> >> considers the PARTID as an internal only value.
> >> …
> >> Perhaps some helpers along the lines of:
> >> int resctrl_mount_generation(void)
> >> …
> > Thank you for the detailed feedback — the concern you raise is valid, particularly when 
> > viewed from the perspective of resctrl-managed deployments.
> > 
> > However, to clarify the intent of this patch: the exposure of partid in the TAD PMU is deliberately
> > a low-level, hardware-facing interface, and is not intended to integrate with or mirror the
> > abstractions provided by resctrl. It is mainly meant for platform bring-up and low-level
> > performance/debug users, who already have explicit knowledge of the MPAM configuration,
> > typically provisioned by firmware or other privileged software layers (e.g. EL3/EL2).
> > In such environments, PARTIDs are known out-of-band, so the expectation is that the
> > user supplying partid is already aware of the MPAM IDs programmed on the system.
> 
> When this was proposed before, [1], there was feedback asking to
> document how to get the PARTID.

Yes, please can you update the documentation to cover this? I'm not
necessarily asking for a programmatic way to do it, but even something
like a reference to a document or a firmware table would be useful for
people trying to use the driver to profile their workload. Otherwise,
it's just an opaque id :/

There are also some comments from Sashiko to consider:

https://sashiko.dev/#/patchset/20260618153610.13649-1-gakula@marvell.com?part=1

Thanks,

Will