linux-kernel - Re: [PATCH v4 6/8] perf cs_etm: Record ts_source in AUXTRACE

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Message-ID: <fb6564d3-c3a2-08c1-32c5-79ba22c69200@arm.com>
Date:   Thu, 19 Jan 2023 15:56:55 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     James Clark <james.clark@....com>,
        linux-perf-users@...r.kernel.org, tanmay@...vell.com,
        leo.yan@...aro.org, mike.leach@...aro.org
Cc:     sgoutham@...vell.com, gcherian@...vell.com, lcherian@...vell.com,
        bbhushan2@...vell.com, German Gomez <german.gomez@....com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        John Garry <john.g.garry@...cle.com>,
        Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 6/8] perf cs_etm: Record ts_source in AUXTRACE_INFO for
 ETMv4 and ETE

On 19/01/2023 15:43, James Clark wrote:
> From: German Gomez <german.gomez@....com>
> 
> Read the value of ts_source exposed by the driver and store it in the
> ETMv4 and ETE header. If the interface doesn't exist (such as in older
> Kernels), defaults to a safe value of -1.

Super minor nits feel free to ignore.

> 
> Signed-off-by: German Gomez <german.gomez@....com>
> Signed-off-by: James Clark <james.clark@....com>
> ---
>   tools/perf/arch/arm/util/cs-etm.c | 48 +++++++++++++++++++++++++++++++
>   tools/perf/util/cs-etm-base.c     |  2 ++
>   tools/perf/util/cs-etm.h          |  2 ++
>   3 files changed, 52 insertions(+)
> 
> diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
> index b526ffe550a5..481e170cd3f1 100644
> --- a/tools/perf/arch/arm/util/cs-etm.c
> +++ b/tools/perf/arch/arm/util/cs-etm.c
> @@ -53,6 +53,7 @@ static const char * const metadata_etmv4_ro[] = {
>   	[CS_ETMV4_TRCIDR2]		= "trcidr/trcidr2",
>   	[CS_ETMV4_TRCIDR8]		= "trcidr/trcidr8",
>   	[CS_ETMV4_TRCAUTHSTATUS]	= "mgmt/trcauthstatus",
> +	[CS_ETMV4_TS_SOURCE]		= "ts_source",
>   };
>   
>   static const char * const metadata_ete_ro[] = {
> @@ -62,6 +63,7 @@ static const char * const metadata_ete_ro[] = {
>   	[CS_ETE_TRCIDR8]		= "trcidr/trcidr8",
>   	[CS_ETE_TRCAUTHSTATUS]		= "mgmt/trcauthstatus",
>   	[CS_ETE_TRCDEVARCH]		= "mgmt/trcdevarch",
> +	[CS_ETE_TS_SOURCE]		= "ts_source",
>   };
>   
>   static bool cs_etm_is_etmv4(struct auxtrace_record *itr, int cpu);
> @@ -613,6 +615,32 @@ static int cs_etm_get_ro(struct perf_pmu *pmu, int cpu, const char *path)
>   	return val;
>   }
>   
> +static int cs_etm_get_ro_signed(struct perf_pmu *pmu, int cpu, const char *path)

minor nit: This doesn't necessarily care if it is RO ?
Also, does it make sense to rename to include cpu relation :

say,  cs_etm_pmu_cpu_get_signed() ?

> +{
> +	char pmu_path[PATH_MAX];
> +	int scan;
> +	int val = 0;
> +
> +	/* Get RO metadata from sysfs */
> +	snprintf(pmu_path, PATH_MAX, "cpu%d/%s", cpu, path);
> +
> +	scan = perf_pmu__scan_file(pmu, pmu_path, "%d", &val);
> +	if (scan != 1)
> +		pr_err("%s: error reading: %s\n", __func__, pmu_path);
> +
> +	return val;
> +}
> +
> +static bool cs_etm_pmu_path_exists(struct perf_pmu *pmu, int cpu, const char *path)

nit: cs_etm_pmu_cpu_path_exists() ? To make the "cpu" relation explicit ?

Otherwise looks good to me.

Suzuki