Re: [PATCH v2 00/16] Consistently prefer sysfs/json events

From: Atish Kumar Patra <atishp@rivosinc.com>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	 Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	 Mark Rutland <mark.rutland@arm.com>,
	 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	 Adrian Hunter <adrian.hunter@intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	 James Clark <james.clark@arm.com>,
	linux-perf-users@vger.kernel.org,  linux-kernel@vger.kernel.org,
	bpf@vger.kernel.org,  linux-riscv@lists.infradead.org,
	Beeman Strong <beeman@rivosinc.com>
Subject: Re: [PATCH v2 00/16] Consistently prefer sysfs/json events
Date: Tue, 23 Apr 2024 17:28:00 -0700	[thread overview]
Message-ID: <CAHBxVyF-u__MY9BNkqxUJg4ra76CzT0p_JBVaQqZm=u4V4u5AQ@mail.gmail.com> (raw)
In-Reply-To: <20240416061533.921723-1-irogers@google.com>

On Mon, Apr 15, 2024 at 11:15 PM Ian Rogers <irogers@google.com> wrote:
>
> As discussed in:
> https://lore.kernel.org/lkml/20240217005738.3744121-1-atishp@rivosinc.com/
> preferring sysfs/json events consistently (with or without a given
> PMU) will enable RISC-V's hope to customize legacy events in the perf
> tool.
>

Thanks for remapping legacy events in a generic way. This looks great
and got rid of my
ugly arch specific way of remapping.  Is there a good way for the
driver (e.g via sysfs) to tell the perf tool
whether to remap the legacy event or not ?

In RISC-V the legacy systems without the new ISA extension may not
want to remap if running
the latest kernel.

I described the problem in detail in the original thread as well.
https://lore.kernel.org/lkml/63d73f09-84e5-49e1-99f5-60f414b22d70@rivosinc.com/

FWIW, for the entire series.
Tested-by: Atish Patra <atishp@rivosinc.com>

> Some minor clean-up is performed on the way.
>
> v2. Additional cleanup particularly adding better error messages. Fix
>     some line length issues on the earlier patches.
>
> Ian Rogers (16):
>   perf parse-events: Factor out '<event_or_pmu>/.../' parsing
>   perf parse-events: Directly pass PMU to parse_events_add_pmu
>   perf parse-events: Avoid copying an empty list
>   perf pmu: Refactor perf_pmu__match
>   perf tests parse-events: Use branches rather than cache-references
>   perf parse-events: Legacy cache names on all PMUs and lower priority
>   perf parse-events: Handle PE_TERM_HW in name_or_raw
>   perf parse-events: Constify parse_events_add_numeric
>   perf parse-events: Prefer sysfs/json hardware events over legacy
>   perf parse-events: Inline parse_events_update_lists
>   perf parse-events: Improve error message for bad numbers
>   perf parse-events: Inline parse_events_evlist_error
>   perf parse-events: Improvements to modifier parsing
>   perf parse-event: Constify event_symbol arrays
>   perf parse-events: Minor grouping tidy up
>   perf parse-events: Tidy the setting of the default event name
>
>  tools/perf/tests/parse-events.c |   6 +-
>  tools/perf/util/parse-events.c  | 482 ++++++++++++++++----------------
>  tools/perf/util/parse-events.h  |  49 ++--
>  tools/perf/util/parse-events.l  | 196 +++++++++----
>  tools/perf/util/parse-events.y  | 261 +++++++----------
>  tools/perf/util/pmu.c           |  27 +-
>  tools/perf/util/pmu.h           |   2 +-
>  7 files changed, 540 insertions(+), 483 deletions(-)
>
> --
> 2.44.0.683.g7961c838ac-goog
>