Re: [PATCH v6 3/6] perf vendor events arm64: Update scale units and descriptions of common topdown metrics

From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: James Clark <james.clark@arm.com>
Cc: linux-perf-users@vger.kernel.org, irogers@google.com,
	john.g.garry@oracle.com, renyu.zj@linux.alibaba.com,
	Will Deacon <will@kernel.org>, Mike Leach <mike.leach@linaro.org>,
	Leo Yan <leo.yan@linaro.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kajol Jain <kjain@linux.ibm.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Haixin Yu <yuhaixin.yhx@linux.alibaba.com>,
	Nick Forrington <nick.forrington@arm.com>,
	Eduard Zingerman <eddyz87@gmail.com>,
	Sohom Datta <sohomdatta1@gmail.com>,
	Rob Herring <robh@kernel.org>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v6 3/6] perf vendor events arm64: Update scale units and descriptions of common topdown metrics
Date: Wed, 16 Aug 2023 13:15:24 -0300	[thread overview]
Message-ID: <ZNz2HO/NGsz+2Qaa@kernel.org> (raw)
In-Reply-To: <20230816114841.1679234-4-james.clark@arm.com>

Em Wed, Aug 16, 2023 at 12:47:45PM +0100, James Clark escreveu:
> Metrics will be published here [1] going forwards, but they have
> slightly different scale units. To allow autogenerated metrics to be
> added more easily, update the scale units to match.
> 
> The more detailed descriptions have also been taken and added to the
> common file.
> 
> [1]: https://gitlab.arm.com/telemetry-solution/telemetry-solution/-/tree/main/data/pmu/cpu/

This one I had cherry-picked and is already in perf-tools-next, I
applied the others locally, will wait till later to see if people
ack/object.

- Arnaldo

> Acked-by: Ian Rogers <irogers@google.com>
> Reviewed-by: John Garry <john.g.garry@oracle.com>
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
>  tools/perf/pmu-events/arch/arm64/sbsa.json | 24 +++++++++++-----------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/tools/perf/pmu-events/arch/arm64/sbsa.json b/tools/perf/pmu-events/arch/arm64/sbsa.json
> index f90b338261ac..4eed79a28f6e 100644
> --- a/tools/perf/pmu-events/arch/arm64/sbsa.json
> +++ b/tools/perf/pmu-events/arch/arm64/sbsa.json
> @@ -1,34 +1,34 @@
>  [
>      {
> -        "MetricExpr": "stall_slot_frontend / (#slots * cpu_cycles)",
> -        "BriefDescription": "Frontend bound L1 topdown metric",
> +        "MetricExpr": "100 * (stall_slot_frontend / (#slots * cpu_cycles))",
> +        "BriefDescription": "This metric is the percentage of total slots that were stalled due to resource constraints in the frontend of the processor.",
>          "DefaultMetricgroupName": "TopdownL1",
>          "MetricGroup": "Default;TopdownL1",
>          "MetricName": "frontend_bound",
> -        "ScaleUnit": "100%"
> +        "ScaleUnit": "1percent of slots"
>      },
>      {
> -        "MetricExpr": "(1 - op_retired / op_spec) * (1 - stall_slot / (#slots * cpu_cycles))",
> -        "BriefDescription": "Bad speculation L1 topdown metric",
> +        "MetricExpr": "100 * ((1 - op_retired / op_spec) * (1 - stall_slot / (#slots * cpu_cycles)))",
> +        "BriefDescription": "This metric is the percentage of total slots that executed operations and didn't retire due to a pipeline flush.\nThis indicates cycles that were utilized but inefficiently.",
>          "DefaultMetricgroupName": "TopdownL1",
>          "MetricGroup": "Default;TopdownL1",
>          "MetricName": "bad_speculation",
> -        "ScaleUnit": "100%"
> +        "ScaleUnit": "1percent of slots"
>      },
>      {
> -        "MetricExpr": "(op_retired / op_spec) * (1 - stall_slot / (#slots * cpu_cycles))",
> -        "BriefDescription": "Retiring L1 topdown metric",
> +        "MetricExpr": "100 * ((op_retired / op_spec) * (1 - stall_slot / (#slots * cpu_cycles)))",
> +        "BriefDescription": "This metric is the percentage of total slots that retired operations, which indicates cycles that were utilized efficiently.",
>          "DefaultMetricgroupName": "TopdownL1",
>          "MetricGroup": "Default;TopdownL1",
>          "MetricName": "retiring",
> -        "ScaleUnit": "100%"
> +        "ScaleUnit": "1percent of slots"
>      },
>      {
> -        "MetricExpr": "stall_slot_backend / (#slots * cpu_cycles)",
> -        "BriefDescription": "Backend Bound L1 topdown metric",
> +        "MetricExpr": "100 * (stall_slot_backend / (#slots * cpu_cycles))",
> +        "BriefDescription": "This metric is the percentage of total slots that were stalled due to resource constraints in the backend of the processor.",
>          "DefaultMetricgroupName": "TopdownL1",
>          "MetricGroup": "Default;TopdownL1",
>          "MetricName": "backend_bound",
> -        "ScaleUnit": "100%"
> +        "ScaleUnit": "1percent of slots"
>      }
>  ]
> -- 
> 2.34.1
> 

-- 

- Arnaldo

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