linux-kernel - Re: [PATCH v3 2/2] perf arm-spe: Add support for SPE Data Source packet on AmpereOne

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Message-ID: <20241107154424.GD47850@e132581.arm.com>
Date: Thu, 7 Nov 2024 15:44:24 +0000
From: Leo Yan <leo.yan@....com>
To: Ilkka Koskinen <ilkka@...amperecomputing.com>
Cc: John Garry <john.g.garry@...cle.com>, Will Deacon <will@...nel.org>,
	James Clark <james.clark@...aro.org>,
	Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...ux.dev>,
	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>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	"Liang, Kan" <kan.liang@...ux.intel.com>,
	Graham Woodward <graham.woodward@....com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] perf arm-spe: Add support for SPE Data Source
 packet on AmpereOne

On Wed, Nov 06, 2024 at 07:37:40PM +0000, Ilkka Koskinen wrote:
> Warning: EXTERNAL SENDER, use caution when opening links or attachments.
> 
> 
> Decode SPE Data Source packets on AmpereOne. The field is IMPDEF.
> 
> Signed-off-by: Ilkka Koskinen <ilkka@...amperecomputing.com>
> ---
>  .../util/arm-spe-decoder/arm-spe-decoder.h    |  9 +++++
>  tools/perf/util/arm-spe.c                     | 39 +++++++++++++++++++
>  2 files changed, 48 insertions(+)
> 
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
> index 358c611eeddb..4bcd627e859f 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
> @@ -67,6 +67,15 @@ enum arm_spe_common_data_source {
>         ARM_SPE_COMMON_DS_DRAM          = 0xe,
>  };
> 
> +enum arm_spe_ampereone_data_source {
> +       ARM_SPE_AMPEREONE_LOCAL_CHIP_CACHE_OR_DEVICE    = 0x0,
> +       ARM_SPE_AMPEREONE_SLC                           = 0x3,
> +       ARM_SPE_AMPEREONE_REMOTE_CHIP_CACHE             = 0x5,
> +       ARM_SPE_AMPEREONE_DDR                           = 0x7,
> +       ARM_SPE_AMPEREONE_L1D                           = 0x8,
> +       ARM_SPE_AMPEREONE_L2D                           = 0x9,
> +};
> +
>  struct arm_spe_record {
>         enum arm_spe_sample_type type;
>         int err;
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index b222557cc27a..40847a3d18b0 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -531,6 +531,44 @@ static void arm_spe__synth_data_source_common(const struct arm_spe_record *recor
>         }
>  }
> 
> +/*
> + * Source is IMPDEF. Here we convert the source code used on AmpereOne cores
> + * to the common (Neoverse, Cortex) to avoid duplicating the decoding code.
> + */
> +static void arm_spe__synth_data_source_ampereone(const struct arm_spe_record *record,
> +                                                union perf_mem_data_src *data_src)
> +{
> +       struct arm_spe_record common_record;
> +
> +       switch (record->source) {
> +       case ARM_SPE_AMPEREONE_LOCAL_CHIP_CACHE_OR_DEVICE:
> +               common_record.source = ARM_SPE_COMMON_DS_PEER_CORE;
> +               break;
> +       case ARM_SPE_AMPEREONE_SLC:
> +               common_record.source = ARM_SPE_COMMON_DS_SYS_CACHE;
> +               break;
> +       case ARM_SPE_AMPEREONE_REMOTE_CHIP_CACHE:
> +               common_record.source = ARM_SPE_COMMON_DS_REMOTE;
> +               break;
> +       case ARM_SPE_AMPEREONE_DDR:
> +               common_record.source = ARM_SPE_COMMON_DS_DRAM;
> +               break;
> +       case ARM_SPE_AMPEREONE_L1D:
> +               common_record.source = ARM_SPE_COMMON_DS_L1D;
> +               break;
> +       case ARM_SPE_AMPEREONE_L2D:
> +               common_record.source = ARM_SPE_COMMON_DS_L2;
> +               break;
> +       default:
> +               /* Assign a bogus value that's not used for common coding */
> +               common_record.source = 0xffff;

For unsupported source value, just bail out and no need to calling
arm_spe__synth_data_source_common().

It is good to use pr_warning_once() to print out warning log to remind
users.

Thanks,
Leo

> +               break;
> +       }
> +
> +       common_record.op = record->op;
> +       arm_spe__synth_data_source_common(&common_record, data_src);
> +}
> +
>  static const struct data_src data_sources[] = {
>         DS(MIDR_ALL_VERSIONS(MIDR_CORTEX_A720), data_source_common),
>         DS(MIDR_ALL_VERSIONS(MIDR_CORTEX_A725), data_source_common),
> @@ -541,6 +579,7 @@ static const struct data_src data_sources[] = {
>         DS(MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N2), data_source_common),
>         DS(MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V1), data_source_common),
>         DS(MIDR_ALL_VERSIONS(MIDR_NEOVERSE_V2), data_source_common),
> +       DS(MIDR_ALL_VERSIONS(MIDR_AMPERE1A), data_source_ampereone),
>         {},
>  };
> 
> --
> 2.47.0
> 
>