Re: [PATCH v9] libperf: Add arm64 support to perf_mmap__read_self()

[John Garry]

On 01/02/2022 21:40, Rob Herring wrote:
> Add the arm64 variants for read_perf_counter() and read_timestamp().
> Unfortunately the counter number is encoded into the instruction, so the
> code is a bit verbose to enumerate all possible counters.
>
> Tested-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>

Ha, I was just looking at this same topic yesterday from an old patchset 
[0] and wasn't aware of this separate change.

Tested-by: John Garry <john.garry@xxxxxxxxxx>

[0] https://lore.kernel.org/all/20210311000837.3630499-1-robh@xxxxxxxxxx/

BTW, Documentation/arm64/perf.rst has a reference to a file which does 
not seem to exit:

.. _tools/perf/arch/arm64/tests/user-events.c:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/arch/arm64/tests/user-events.c

Thanks,
john