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

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Date: Tue, 23 Apr 2024 17:28:00 -0700
From: Atish Kumar Patra <atishp@...osinc.com>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	James Clark <james.clark@....com>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org, bpf@...r.kernel.org, 
	linux-riscv@...ts.infradead.org, Beeman Strong <beeman@...osinc.com>
Subject: Re: [PATCH v2 00/16] Consistently prefer sysfs/json events

On Mon, Apr 15, 2024 at 11:15 PM Ian Rogers <irogers@...gle.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@...osinc.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
>