Re: [PATCH v2] perf vendor events arm64 AmpereOneX: Deprecate BPU_FLUSH_MEM_FAULT

[James Clark <james.clark@linaro.org>]

On 03/11/2026 11:26, TAKANO Mitsuhiro wrote:
> AmpereOne named event 0x121 BPU_FLUSH_MEM_FAULT until
> commit 10a149e4b4a9 ("perf vendor events arm64 AmpereOne: Rename
> BPU_FLUSH_MEM_FAULT to GPC_FLUSH_MEM_FAULT") renamed it.  The next patch
> in that series, 16438b652b46, added the AmpereOneX tables with the old
> name in memory.json, so 0x121 carries two names: GPC_FLUSH_MEM_FAULT in
> core-imp-def.json and BPU_FLUSH_MEM_FAULT in memory.json, and the
> default perf list output shows both.  The old name has been in every
> release since v6.8, so deleting it would break scripts that use it.
> 
> Mark the entry deprecated instead of deleting it, as Ian Rogers asked:
> perf list then shows 0x121 once while those scripts keep working.  The
> x86 tables use the same wording, and
> commit eda39f98bbc5 ("perf vendor events amd: Reintroduce deprecated
> Zen 5 core events") brought back deprecated AMD events for the same
> reason.  The flag is only read when listing; the entry still registers
> event=0x121, so perf stat -e bpu_flush_mem_fault resolves as before, and
> regenerating the tables changes nothing but that flag.
> perf list --deprecated still prints the name in the text output; the
> JSON path does not consult the flag, so perf list -j cannot show it.
> No metric expression and no other file refers to either name.
> 
> The duplicate came in because jevents checks repeated names, not event
> codes, and one encoding carrying several names is legitimate, so nothing
> is added for that here.  No AmpereOneX machine was available, so the
> listing was not run on hardware; Ilkka Koskinen, who added both tables,
> tried v1 and v2 and reports that they behave as expected, and his
> Acked-by is for this variant.  The JSON edit and this changelog were
> written with an LLM assistant, Hermes Agent, working from the code and
> the thread; the checks above were run here.
> 
> Fixes: 16438b652b46 ("perf vendor events arm64 AmpereOneX: Add core PMU events and metrics")
> Suggested-by: Ian Rogers <irogers@google.com>
> Link: https://lore.kernel.org/20261021224527.167637-1-takano32@gmail.com
> Link: https://lore.kernel.org/CAP-5=fX+2eRGCHcU43sqU=gi9iKvxqyS6ipwRSnvFcap3D+QzQ@mail.gmail.com
> Link: https://lore.kernel.org/42801873-8908-07a6-aed1-c7076c689e8e@os.amperecomputing.com
> Acked-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
> Signed-off-by: TAKANO Mitsuhiro <takano32@gmail.com>
> ---
> v2: keep the entry and mark it deprecated instead of deleting it,
>      as Ian Rogers suggested, and word both descriptions the way
>      the x86 tables do.  Ilkka Koskinen Acked-by v1 and asked for it
>      to be carried over to v2; the description wording was added on
>      top of that, as said in this thread.
> v1: https://lore.kernel.org/20261021224527.167637-1-takano32@gmail.com
> 
>   .../perf/pmu-events/arch/arm64/ampere/ampereonex/memory.json | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/pmu-events/arch/arm64/ampere/ampereonex/memory.json b/tools/perf/pmu-events/arch/arm64/ampere/ampereonex/memory.json
> index 6c06bc928415..114f95e41e0d 100644
> --- a/tools/perf/pmu-events/arch/arm64/ampere/ampereonex/memory.json
> +++ b/tools/perf/pmu-events/arch/arm64/ampere/ampereonex/memory.json
> @@ -35,9 +35,10 @@
>           "ArchStdEvent": "MEM_ACCESS_CHECKED_WR"
>       },
>       {
> -        "PublicDescription": "Flushes due to memory hazards",
> +        "PublicDescription": "This event is deprecated. Refer to new event GPC_FLUSH_MEM_FAULT Flushes due to memory hazards",

Extremely minor nit, but there should be a full stop before 'Flushes'. 
But if marking it deprecated makes it not show in Perf list, then it 
doesn't make a difference.

Reviewed-by: James Clark <james.clark@linaro.org>

>           "EventCode": "0x121",
>           "EventName": "BPU_FLUSH_MEM_FAULT",
> -        "BriefDescription": "Flushes due to memory hazards"
> +        "BriefDescription": "This event is deprecated. Refer to new event GPC_FLUSH_MEM_FAULT",
> +        "Deprecated": "1"
>       }
>   ]
> 
> base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4