Re: [PATCH 1/4] perf vendor events amd: Add Zen 5 core events

[Ian Rogers]

On Sun, Mar 10, 2024 at 10:23 PM Sandipan Das <sandipan.das@xxxxxxx> wrote:
>
> Add core events taken from Section 1.4 "Core Performance Monitor
> Counters" of the Performance Monitor Counters for AMD Family 1Ah Model
> 00h-0Fh Processors document available at the link below. This
> constitutes events which capture information on op dispatch, execution
> and retirement, branch prediction, L1 and L2 cache activity,
> TLB activity, etc.
>
> Link: https://bugzilla.kernel.org/attachment.cgi?id=305974
> Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx>
> ---
>  .../pmu-events/arch/x86/amdzen5/branch.json   |  82 ++
>  .../pmu-events/arch/x86/amdzen5/cache.json    | 605 +++++++++++++
>  .../pmu-events/arch/x86/amdzen5/core.json     | 122 +++
>  .../arch/x86/amdzen5/floating-point.json      | 830 ++++++++++++++++++
>  .../pmu-events/arch/x86/amdzen5/memory.json   | 180 ++++
>  .../pmu-events/arch/x86/amdzen5/other.json    | 168 ++++
>  6 files changed, 1987 insertions(+)
>  create mode 100644 tools/perf/pmu-events/arch/x86/amdzen5/branch.json
>  create mode 100644 tools/perf/pmu-events/arch/x86/amdzen5/cache.json
>  create mode 100644 tools/perf/pmu-events/arch/x86/amdzen5/core.json
>  create mode 100644 tools/perf/pmu-events/arch/x86/amdzen5/floating-pointjson
>  create mode 100644 tools/perf/pmu-events/arch/x86/amdzen5/memory.json
>  create mode 100644 tools/perf/pmu-events/arch/x86/amdzen5/other.json
>
> diff --git a/tools/perf/pmu-events/arch/x86/amdzen5/branch.json b/tools/perf/pmu-events/arch/x86/amdzen5/branch.json
> new file mode 100644
> index 000000000000..208c646c59ca
> --- /dev/null
> +++ b/tools/perf/pmu-events/arch/x86/amdzen5/branch.json
> @@ -0,0 +1,82 @@
> +[
> +  {
> +    "EventName": "bp_l2_btb_correct",
> +    "EventCode": "0x8b",
> +    "BriefDescription": "L2 branch prediction overrides existing prediction (speculative)."
> +  },
> +  {
> +    "EventName": "bp_dyn_ind_pred",
> +    "EventCode": "0x8e",
> +    "BriefDescription": "Dynamic indirect predictions (branch used the indirect predictor to make a prediction)."
> +  },
> +  {
> +    "EventName": "bp_de_redirect",
> +    "EventCode": "0x91",
> +    "BriefDescription": "Instruction decoder corrects the predicted target and resteers the branch predictor."
> +  },
> +  {
> +    "EventName": "ex_ret_brn",
> +    "EventCode": "0xc2",
> +    "BriefDescription": "Retired branch instructions (all types of architectural control flow changes, including exceptions and interrupts)."
> +  },

So the "bp_" prefix means branch predictor, but here this is an "ex_"
prefix. You've put them both in the topic "branch".

[ ... snip ... ]

> diff --git a/tools/perf/pmu-events/arch/x86/amdzen5/other.json b/tools/perf/pmu-events/arch/x86/amdzen5/other.json
> new file mode 100644
> index 000000000000..9d49a23622e9
> --- /dev/null
> +++ b/tools/perf/pmu-events/arch/x86/amdzen5/other.json
> @@ -0,0 +1,168 @@
> +[
> +  {
> +    "EventName": "bp_redirects.resync",
> +    "EventCode": "0x9f",
> +    "BriefDescription": "Redirects of the branch predictor caused by resyncs.",
> +    "UMask": "0x01"
> +  },

Here is a branch predictor "bp_" event but the topic is "other", why
isn't it a topic of branch?

Given the number of events categorized as topic "other" wouldn't it be
better to regenerate the events just using the prefix to set the
topic?

Thanks,
Ian

[ ... snip ... ]