[PATCH v2] perf arm-spe: Report error if set frequency
James Clark
james.clark at linaro.org
Thu Feb 27 02:36:50 PST 2025
On 27/02/2025 8:55 am, Leo Yan wrote:
> When users set the parameter '-F' to specify frequency for Arm SPE, the
> tool reports error:
>
> perf record -F 1000 -e arm_spe_0// -- sleep 1
> Error:
> Invalid event (arm_spe_0//) in per-thread mode, enable system wide with '-a'.
>
> The output logs are confused and it does not give the correct reminding.
> Arm SPE does not support frequency setting given it adopts a statistical
> based approach.
>
> Alternatively, Arm SPE supports setting period. This commit adds a
> for frequency setting. It reports error and reminds users to set period
> instead.
>
> After:
>
> perf record -F 1000 -e arm_spe_0// -- sleep 1
> Arm SPE: Frequency is not supported. Set period with -c option or PMU parameter (-e arm_spe_0/period=NUM/).
>
> Signed-off-by: Leo Yan <leo.yan at arm.com>
> ---
>
> Changes from v1:
> - Sugguested users for '-c' option or PMU parameter 'period' in the log
> (Namhyung)
>
> tools/perf/arch/arm64/util/arm-spe.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> index 4301181b8e45..4f2833b62ff5 100644
> --- a/tools/perf/arch/arm64/util/arm-spe.c
> +++ b/tools/perf/arch/arm64/util/arm-spe.c
> @@ -40,6 +40,19 @@ struct arm_spe_recording {
> bool *wrapped;
> };
>
> +/* Iterate config list to detect if the "freq" parameter is set */
> +static bool arm_spe_is_set_freq(struct evsel *evsel)
> +{
> + struct evsel_config_term *term;
> +
> + list_for_each_entry(term, &evsel->config_terms, list) {
> + if (term->type == EVSEL__CONFIG_TERM_FREQ)
> + return true;
> + }
> +
> + return false;
> +}
> +
> /*
> * arm_spe_find_cpus() returns a new cpu map, and the caller should invoke
> * perf_cpu_map__put() to release the map after use.
> @@ -389,6 +402,14 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
> return -EINVAL;
> }
> opts->full_auxtrace = true;
> +
> + if (opts->user_freq != UINT_MAX ||
> + arm_spe_is_set_freq(evsel)) {
> + pr_err("Arm SPE: Frequency is not supported. "
> + "Set period with -c option or PMU parameter (-e %s/period=NUM/).\n",
> + evsel->pmu->name);
> + return -EINVAL;
> + }
> }
> }
>
Reviewed-by: James Clark <james.clark at linaro.org>
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