Re: [PATCH] drm/xe/oa: Enable Xe2+ PES disaggregation

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Wed, 11 Sep 2024 08:58:30 -0700, Lucas De Marchi wrote:
>
> On Tue, Sep 10, 2024 at 10:03:56PM GMT, Ashutosh Dixit wrote:
> > On Tue, 10 Sep 2024 17:57:59 -0700, Lucas De Marchi wrote:
> >>
> >> On Tue, Sep 10, 2024 at 05:40:02PM GMT, Ashutosh Dixit wrote:
> >> > On Tue, 10 Sep 2024 10:04:32 -0700, Lucas De Marchi wrote:
> >> >>
> >> >
> >> > Hi Lucas,
> >> >
> >> > We had a whole email thread to figure this out :/
> >> >
> >> >> On Mon, Sep 09, 2024 at 09:59:33AM GMT, Ashutosh Dixit wrote:
> >> >> > Xe2+ PES disaggregation for OAG needs to be enabled to obtain disaggregated
> >> >> > metrics when disaggregated data is needed. There is no uapi impact of this
> >> >>
> >> >> it looks like the *control* for disaggregated data is only available on
> >> >> xe2
> >> >
> >> > Correct, that is why the check below (also this is available only for OAG,
> >> > not say for OAM):
> >> >
> >> >	if (GRAPHICS_VER(stream->oa->xe) >= 20 &&
> >> >	    stream->hwe->oa_unit->type == DRM_XE_OA_UNIT_TYPE_OAG)
> >> >
> >> >> and we always use disaggregated, right?
> >> >
> >> > No we don't, please see below.
> >> >
> >> >>
> >> >> > change.
> >> >> >
> >> >> > v2: Minor change to commit message
> >> >> >
> >> >> > Bspec: 61101
> >> >>
> >> >> "Note: After enabling desired disaggregation mode/s using this control
> >> >> field, PES MODE_SELECT field is used to configure appropriate
> >> >> disaggregation mode of corresponding PEC."
> >> >>
> >> >> Apparently MODE_SELECT == Aggregated is the hw default for xe2. Don't
> >> >> we need to program anything else?
> >> >
> >> > So the code in this patch only enables disaggregation, this additional step
> >> > (PES_MODE_SELECT) is still needed to actually use disaggregation. However
> >> > this second step is done via OA configurations which come in from userspace
> >> > (using add_config observation stream op). So userspace can request either
> >> > aggregated or disaggregated data depending on the OA config it programs.
> >> >
> >> > The goal of this patch is only to enable disaggregation so userspace can
> >> > use it if they want, otherwise they can't, they can only use
> >> > aggregated.
> >>
> >> can you add a paragraph to the commit message stating something like
> >> above?  Because it was not clear it was intentional to enable it in the
> >> control and not in the PES_MODE_SELECT.
> >
> > I have changed the commit message to the following:
> >
> > "
> > Enable Xe2+ PES disaggregation (for OAG) to retrieve disaggregated metrics
> > when disaggregated data is needed. Userspace can select whether to receive
> > aggregated or disaggregated metrics via the particular OA configuration it
> > uses (programmed via DRM_XE_OBSERVATION_OP_ADD_CONFIG).
> > "
>
> looks good to me.

Thanks, patch is now merged to drm-xe-next.

Ashutosh