RE: [PATCH 0/6] perf jevents: Add NVIDIA Tegra410 uncore PMU events and metrics

[Besar Wicaksono]

> -----Original Message-----
> From: Ian Rogers <irogers@xxxxxxxxxx>
> Sent: Tuesday, October 20, 2026 8:33 PM
> To: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: James Clark <james.clark@xxxxxxxxxx>; Besar Wicaksono
> <bwicaksono@xxxxxxxxxx>; namhyung@xxxxxxxxxx; linux-
> tegra@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-perf-
> users@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Vikram Sethi
> <vsethi@xxxxxxxxxx>; Rich Wiley <rwiley@xxxxxxxxxx>; Sean Kelley
> <skelley@xxxxxxxxxx>; Matt Ochs <mochs@xxxxxxxxxx>; Raj Joshi
> <rajjoshi@xxxxxxxxxx>; Thierry Reding <treding@xxxxxxxxxx>; Jon Hunter
> <jonathanh@xxxxxxxxxx>; john.garry@xxxxxxxxx; will@xxxxxxxxxx;
> mike.leach@xxxxxxx; leo.yan@xxxxxxxxx; mark.rutland@xxxxxxx;
> alexander.shishkin@xxxxxxxxxxxxxxx; jolsa@xxxxxxxxxx;
> adrian.hunter@xxxxxxxxx; ctshao@xxxxxxxxxx
> Subject: Re: [PATCH 0/6] perf jevents: Add NVIDIA Tegra410 uncore PMU
> events and metrics
> 
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> 
> On Tue, Oct 20, 2026 at 12:15 PM Arnaldo Carvalho de Melo
> <acme@xxxxxxxxxx> wrote:
> >
> > On Mon, Oct 19, 2026 at 06:23:16PM +0100, James Clark wrote:
> > > On 19/10/2026 17:42, Besar Wicaksono wrote:
> > > > Add event aliases and derived metrics for the NVIDIA Tegra410 uncore
> > > > PMUs.
> >
> > > Reviewed-by: James Clark <james.clark@xxxxxxxxxx>
> >
> > Thanks, applied to perf-tools-next, for v7.4.
> 
> Hi Arnaldo,
> 
> can we not take these in v7.4 as there is unaddressed feedback:
> https://lore.kernel.org/linux-perf-users/CAP-
> 5=fWucvdYefDOL3Vn=O=YUPEXE+tngDDfPLv-
> T5i3WkCJVA@xxxxxxxxxxxxxx/
> 
> The specific problem is that the NVidia PMUs have adopted a convention
> not supported by the perf tool of 'pmu_name_<socket>_rc_<num>'. rc
> stands for root complex. What ends up happening is that aggregation is
> broken as the json is claiming that pmu_name is the PMU's name while
> the suffix perf_pmus code thinks pmu_name_<socket>_rc is the pmu name.
> They've wrangled support via the json by claiming these are sys
> events.
> 
> We can either:
> 1) support a new suffix convention of <num>_rc_<num>
> 2) push back and ask the driver writers to name their PMU correctly as
> defined in the ABI:
> https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree
> /Documentation/ABI/testing/sysfs-bus-event_source-devices
> 
> If we do (1) then it would be nice if the support for that could be
> contained in this patch series. In any case these events don't belong
> in sys.

Hi Ian,

Could you elaborate more on why these uncore events don't belong in sys
directory? Is it because T410 already has an entry in mapfile.csv?

I put them in sys so perf matches them to the PMU by its identifier ("Compat")
rather than by the CPU, similar to hisilicon/hip09/sys and thead/yitian710/sys.

For the aggregation concern, I replied on PATCH 4/6 and will look into
it further.

Thanks,
Besar

> 
> Thanks,
> Ian
> 
> > - Arnaldo