Re: [PATCH v2 0/4] Perf tool: Enable Arm arch timer counter and arm-spe's timestamp

From: John Garry
Date: Thu Aug 13 2020 - 08:10:29 EST

On 13/08/2020 12:18, Will Deacon wrote:
[ Adding John, as I only just realised he wasn't on CC and we were talking
about him! ]

On Thu, Aug 13, 2020 at 10:59:01AM +0100, Will Deacon wrote:
On Wed, Aug 12, 2020 at 03:53:34PM -0300, Arnaldo Carvalho de Melo wrote:
Em Wed, Aug 12, 2020 at 10:06:53AM -0600, Mathieu Poirier escreveu:
The ARM SPE perf tools code is orphan and I don't have the cycles to
pick it up. Leo has spent a lot of time in that code and as such I
suggest that he starts maintaining it, probably following the same
kind of arrangement you and I have for coresight.

Thats ok with me, I think we should reflect that on the MAINTAINERS
file, right?

We have this already:

R: John Garry <john.garry@xxxxxxxxxx>
R: Will Deacon <will@xxxxxxxxxx>
L: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx (moderated for non-subscribers)
S: Supported
F: tools/perf/pmu-events/arch/arm64/

I think we should have entries for CoreSight and ARM SPE, one listing
you as the maintainer and the other listing Leo, right?

Fine by me. I'll continue to maintain the in-kernel SPE driver, but I'd love
to see somebody step up to looking after the userspace code. It's seriously
unloved on arm64 :(

I'd even be happy to see one or two M: entries added for
tools/perf/pmu-events/arch/arm64/. I realistically don't have the time to
take that on, but I'd be thrilled if any/all of John, Mathieu and Leo were
to be listed there if they are willing to do so and can spare the time to
look after it. Even just silly things like making sure the thing
cross-compiles have been broken in the recent past, so it's not necessarily
about handling huge amounts of incoming patches.

In other words, rather than slice up the arm64 parts of the perf tool, I'd
argue in favour of a joint maintainership model for all the arm64 bits, if
we have a few willing volunteers.

Right, it makes sense not to chop up too much, so happy to see "PERFORMANCE EVENTS SUBSYSTEM ARM64 PMU EVENTS" expanded in terms of scope and membership.