Re: [PATCH 0/2] perf vendor events arm64: Add A720/A520 events/metrics

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Feb 18, 2025 at 09:30:23AM +0000, James Clark wrote:
> 
> 
> On 18/02/2025 12:41 am, Ian Rogers wrote:
> > On Fri, Feb 14, 2025 at 2:02 AM James Clark <james.clark@linaro.org> wrote:
> > > 
> > > 
> > > 
> > > On 14/02/2025 5:49 am, Yangyu Chen wrote:
> > > > 
> > > > 
> > > > > On 14 Feb 2025, at 09:12, Namhyung Kim <namhyung@kernel.org> wrote:
> > > > > 
> > > > > Hello,
> > > > > 
> > > > > On Thu, Feb 13, 2025 at 11:11:01PM +0800, Yangyu Chen wrote:
> > > > > > This patchset adds the perf JSON files for the Cortex-A720 and Cortex-A520
> > > > > > processors. Some events have been tested on Raxda Orion 6 with Cix P1 SoC
> > > > > > (8xA720 + 4xA520) running mainline Kernel with ACPI mode.
> > > > > 
> > > > > I'm curious how the name of PMUs look like.  It is cortex_a720 (or a520)?
> > > > 
> > > > The name of PMUs comes from Arm's documentation. I have included these
> > > > links in each patch.
> > > > 
> > > > > I remember there's a logic to check the length of hex digits at the end.
> > > > > 
> > > > 
> > > > Could you provide more details about this?
> > > > 
> > > > > Ian, are you ok with this?
> > > > > 
> > > 
> > > I think they wouldn't be merged because they're core PMUs, so should be
> > > fine? Even though they would otherwise be merged because they're more
> > > than 3 hex digits.
> > 
> > Do we know the PMU names? If they are cortex_a520 and cortex_a720 then
> 
> It will be "armv9_cortex_a720" from this line:
> 
>   PMUV3_INIT_SIMPLE(armv9_cortex_a720)

I see, thanks!

> 
> > this comment at least reads a little stale:
> > https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/util/pmus.c?h=perf-tools-next#n76
> > ```
> > /*
> > * There is a '_{num}' suffix. For decimal suffixes any length
> > * will do, for hexadecimal ensure more than 2 hex digits so
> > * that S390's cpum_cf PMU doesn't match.
> > */
> > ```
> > James is right that core PMUs aren't put on the same list as uncore/other PMUs.

Ok, then I guess we're good.

Thanks,
Namhyung