Re: [PATCH v7 00/27] Legacy hardware/cache events as json

[Ian Rogers]

On Wed, Oct 8, 2025 at 4:06 AM James Clark <james.clark@xxxxxxxxxx> wrote:
> On 05/10/2025 7:24 pm, Ian Rogers wrote:
> > Mirroring similar work for software events in commit 6e9fa4131abb
> > ("perf parse-events: Remove non-json software events"). These changes
> > migrate the legacy hardware and cache events to json.  With no hard
> > coded legacy hardware or cache events the wild card, case
> > insensitivity, etc. is consistent for events. This does, however, mean
> > events like cycles will wild card against all PMUs. A change doing the
> > same was originally posted and merged from:
> > https://lore.kernel.org/r/20240416061533.921723-10-irogers@xxxxxxxxxx
> > and reverted by Linus in commit 4f1b067359ac ("Revert "perf
> > parse-events: Prefer sysfs/JSON hardware events over legacy"") due to
> > his dislike for the cycles behavior on ARM with perf record. Earlier
> > patches in this series make perf record event opening failures
> > non-fatal and hide the cycles event's failure to open on ARM in perf
> > record, so it is expected the behavior will now be transparent in perf
> > record on ARM. perf stat with a cycles event will wildcard open the
> > event on all PMUs, however, with default events the cycles event will
> > only be opened on core PMUs.
> >
>
> Hi Ian,
>
> The previous issues seem to be fixed, I don't see any Perf test
> regressions or issues when there is an uncore PMU with a cycles event.
>
> Tested-by: James Clark <james.clark@xxxxxxxxxx>

Thanks James!

Ian