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: <f84d3b6-ccea-bcc-b628-4966fa19f227@os.amperecomputing.com>
Date: Thu, 7 Nov 2024 15:56:51 -0800 (PST)
From: Ilkka Koskinen <ilkka@...amperecomputing.com>
To: Leo Yan <leo.yan@....com>
cc: Ilkka Koskinen <ilkka@...amperecomputing.com>, 
    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 Thu, 7 Nov 2024, Leo Yan wrote:
> 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.

Hi Leo,

Makes sense, I'll do that.

--Ilkka

>
> 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
>>
>>
>