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

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Wed, 12 Aug 2020 at 12:53, Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
>
> Em Wed, Aug 12, 2020 at 10:06:53AM -0600, Mathieu Poirier escreveu:
> > Hi Arnaldo,
> >
> > On Fri, 7 Aug 2020 at 01:16, Leo Yan <leo.yan@linaro.org> wrote:
> > >
> > > This patch set is to enable Arm arch timer counter and Arm SPE is the
> > > first customer to use arch timer counter for its timestamp.
> > >
> > > Patches 01 ~ 03 enables Arm arch timer counter in Perf tool; patch 01 is
> > > to retrieve arch timer's parameters from mmaped page; patch 02 provides
> > > APIs for the conversion between arch timer's counter and time; patch 03
> > > adds a test for patches 01 and 02.
> > >
> > > As the first customer to use Arm arch timer counter in perf tool, patch
> > > 04 is to generate sample's timestamp for ARM SPE AUX trace data.
> > >
> > > This patch set has been rebased on perf/core branch with the latest
> > > commit c4735d990268 ("perf evsel: Don't set
> > > sample_regs_intr/sample_regs_user for dummy event").
> >
> > 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?
>

I agree, it is time to sort out this part.

> We have this already:
>
> PERFORMANCE EVENTS SUBSYSTEM ARM64 PMU EVENTS
> R:      John Garry <john.garry@huawei.com>
> R:      Will Deacon <will@kernel.org>
> L:      linux-arm-kernel@lists.infradead.org (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?
>

Yes - I'll send you a patch for that once v5.9-rc1 comes out (unless
you want it now).

> Leo, it would be good for you to try and find someone at your
> organization or elsewhere that could help with this, this way I would
> wait a bit, see if someone else Acks it, and collect those, processing
> it from you after a while if nobody chimes in.
>

Right, the same kind of arrangement you and I have for coresight.  So
far this has worked quite well and I don't see a need to proceed
differently.

> Please continue providing 'perf test' regression tests, etc, to help
> with maintaining this code being checked.

Those are quite useful.

>
> - Arnaldo
>
> > Thanks,
> > Mathieu
> >
> > >
> > > After changes:
> > >
> > >   # perf test 67 -v
> > >     67: Convert perf time to arch timer counter
> > >     --- start ---
> > >     test child forked, pid 5463
> > >     mmap size 528384B
> > >     1st event perf time 2231755083020 arch timer cnt 113097053477
> > >     test time           2231755087460 arch timer cnt 113097053699
> > >     2nd event perf time 2231755090680 arch timer cnt 113097053860
> > >     test child finished with 0
> > >     ---- end ----
> > >
> > >   Reports the SPE sample with timestamp:
> > >
> > >   $ perf script -F,+time
> > >     dd  6799 [034] 25496.733475:          1              l1d-access:      ffff87f37b88 _dl_start+0x288 (/usr/lib/aarch64-linux-gnu/ld-2.28.so)
> > >     dd  6799 [034] 25496.733475:          1              tlb-access:      ffff87f37b88 _dl_start+0x288 (/usr/lib/aarch64-linux-gnu/ld-2.28.so)
> > >     dd  6799 [034] 25496.733479:          1              l1d-access:      ffff87f37c74 _dl_start+0x374 (/usr/lib/aarch64-linux-gnu/ld-2.28.so)
> > >     dd  6799 [034] 25496.733479:          1              tlb-access:      ffff87f37c74 _dl_start+0x374 (/usr/lib/aarch64-linux-gnu/ld-2.28.so)
> > >     dd  6799 [034] 25496.733485:          1              l1d-access:      ffff87f49af4 __GI___tunables_init+0x3c (/usr/lib/aarch64-linux-gnu/ld-2.28.so)
> > >     dd  6799 [034] 25496.733485:          1              tlb-access:      ffff87f49af4 __GI___tunables_init+0x3c (/usr/lib/aarch64-linux-gnu/ld-2.28.so)
> > >
> > > Changes from v1:
> > > * Rebased on the latest perf/core branch;
> > > * Added a testing for Arm timer counter conversion (Ian Rogers).
> > >
> > >
> > > Leo Yan (4):
> > >   perf tools: Support Arm arch timer counter
> > >   perf arm_arch_timer: Convert between counter and timestamp
> > >   perf arm_arch_timer: Test conversion between counter and timestamp
> > >   perf arm-spe: Enable timestamp with arch timer counter
> > >
> > >  tools/perf/arch/arm64/include/arch-tests.h    |   6 +
> > >  tools/perf/arch/arm64/tests/Build             |   1 +
> > >  tools/perf/arch/arm64/tests/arch-tests.c      |   4 +
> > >  .../tests/perf-time-to-arch-timer-counter.c   | 189 ++++++++++++++++++
> > >  tools/perf/arch/arm64/util/Build              |   1 +
> > >  tools/perf/arch/arm64/util/arch_timer.c       |  50 +++++
> > >  tools/perf/arch/arm64/util/arm-spe.c          |  17 ++
> > >  tools/perf/util/Build                         |   1 +
> > >  tools/perf/util/arm-spe.c                     |  16 +-
> > >  tools/perf/util/arm-spe.h                     |   5 +
> > >  tools/perf/util/arm_arch_timer.c              |  28 +++
> > >  tools/perf/util/arm_arch_timer.h              |  23 +++
> > >  12 files changed, 339 insertions(+), 2 deletions(-)
> > >  create mode 100644 tools/perf/arch/arm64/tests/perf-time-to-arch-timer-counter.c
> > >  create mode 100644 tools/perf/arch/arm64/util/arch_timer.c
> > >  create mode 100644 tools/perf/util/arm_arch_timer.c
> > >  create mode 100644 tools/perf/util/arm_arch_timer.h
> > >
> > > --
> > > 2.17.1
> > >
>
> --
>
> - Arnaldo