Re: [PATCH v5] perf script: Fix output type for dynamically allocated core PMU's

[Ian Rogers]

On Mon, Mar 3, 2025 at 5:39 PM Thomas Falcon <thomas.falcon@xxxxxxxxx> wrote:
>
> This patch was originally posted here:
>
> https://lore.kernel.org/all/20241213215421.661139-1-thomas.falcon@xxxxxxxxx/
>
> I have rebased on top of Arnaldo's patch here:
>
> https://lore.kernel.org/all/Z2XCi3PgstSrV0SE@x1/
>
> The original commit message:
> "
> perf script output may show different fields on different core PMU's
> that exist on heterogeneous platforms. For example,
>
> perf record -e "{cpu_core/mem-loads-aux/,cpu_core/event=0xcd,\
> umask=0x01,ldlat=3,name=MEM_UOPS_RETIRED.LOAD_LATENCY/}:upp"\
> -c10000 -W -d -a -- sleep 1
>
> perf script:
>
> chromium-browse   46572 [002] 544966.882384:      10000         cpu_core/MEM_UOPS_RETIRED.LOAD_LATENCY/: 7ffdf1391b0c     10268100142 \
>  |OP LOAD|LVL L1 hit|SNP None|TLB L1 or L2 hit|LCK No|BLK    N/A    5   7    0   7fad7c47425d [unknown] (/usr/lib64/libglib-2.0.so.0.8000.3)
>
> perf record -e cpu_atom/event=0xd0,umask=0x05,ldlat=3,\
> name=MEM_UOPS_RETIRED.LOAD_LATENCY/upp -c10000 -W -d -a -- sleep 1
>
> perf script:
>
> gnome-control-c  534224 [023] 544951.816227:      10000 cpu_atom/MEM_UOPS_RETIRED.LOAD_LATENCY/:   7f0aaaa0aae0  [unknown] (/usr/lib64/libglib-2.0.so.0.8000.3)
>
> Some fields, such as data_src, are not included by default.
>
> The cause is that while one PMU may be assigned a type such as
> PERF_TYPE_RAW, other core PMU's are dynamically allocated at boot time.
> If this value does not match an existing PERF_TYPE_X value,
> output_type(perf_event_attr.type) will return OUTPUT_TYPE_OTHER.
>
> Instead search for a core PMU with a matching perf_event_attr type
> and, if one is found, return PERF_TYPE_RAW to match output of other
> core PMU's.
> "
>
> Suggested-by: Kan Liang <kan.liang@xxxxxxxxx>
> Signed-off-by: Thomas Falcon <thomas.falcon@xxxxxxxxx>
> ---
> v2: restrict pmu lookup to platforms with more than one core pmu
> v3: only scan core pmu list
> v4: rebase on top of Arnaldo's patch
> v5: update based on Namhyung's feedback here
> https://lore.kernel.org/lkml/Z8YcOidenzGofq7R@xxxxxxxxxx/
> ---
>  tools/perf/builtin-script.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index d797cec4f054..4d2764df48a0 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -385,6 +385,19 @@ static int evsel_script__fprintf(struct evsel_script *es, FILE *fp)
>                        st.st_size / 1024.0 / 1024.0, es->filename, es->samples);
>  }
>
> +static bool is_core_pmu_type(unsigned int type)
> +{
> +       struct perf_pmu *pmu = NULL;
> +
> +       if (perf_pmus__num_core_pmus() > 1) {

On ARM it isn't a given that if there is 1 core PMU the type will be
PERF_TYPE_RAW, on x86 this is normally the case.

> +               while ((pmu = perf_pmus__scan_core(pmu)) != NULL) {
> +                       if (pmu->type == type)
> +                               return true;
> +               }
> +       }
> +       return type == PERF_TYPE_RAW;
> +}
> +
>  static inline int output_type(unsigned int type)
>  {
>         switch (type) {
> @@ -395,6 +408,9 @@ static inline int output_type(unsigned int type)
>                         return type;
>         }
>
> +       if (is_core_pmu_type(type))

Given this is called by evsel__output_type I think you can do:
```
static inline int output_type(unsigned int type)
{
       switch (type) {
       case PERF_TYPE_SYNTH:
               return OUTPUT_TYPE_SYNTH;
       default:
               if (type < PERF_TYPE_MAX)
                       return type;
       }

       return OUTPUT_TYPE_OTHER;
}

static inline int evsel__output_type(struct evsel *evsel)
{
       int output_type = evsel->script_output_type;

       if (output_type == OUTPUT_TYPE_UNSET) {
               output_type = output_type(evsel->core.attr.type);
               if (output_type == OUTPUT_TYPE_OTHER) {
                      struct perf_pmu *pmu = evsel__find_pmu(evsel);

                      if (pmu && pmu->is_core)
                             output_type = PERF_TYPE_RAW;
               }
               evsel->script_output_type = output_type;

       return output_type;
}
```
The evsel__find_pmu will cache the PMU for future callers.

Thanks,
Ian

> +               return PERF_TYPE_RAW;
> +
>         return OUTPUT_TYPE_OTHER;
>  }
>
> --
> 2.48.1
>