Re: [PATCH v3] perf script: Fix output type for dynamically allocated core PMU's

[Arnaldo Carvalho de Melo]

On Fri, Dec 13, 2024 at 03:54:21PM -0600, Thomas Falcon wrote:
> 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
> ---
>  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 9e47905f75a6..685232883f9c 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -384,6 +384,19 @@ static int evsel_script__fprintf(struct evsel_script *es, FILE *fp)
>  		       st.st_size / 1024.0 / 1024.0, es->filename, es->samples);
>  }
>  
> +static bool output_type_many_core_pmus(unsigned int type)
> +{
> +	struct perf_pmu *pmu = NULL;
> +
> +	if (perf_pmus__num_core_pmus() > 1) {
> +		while ((pmu = perf_pmus__scan_core(pmu)) != NULL) {
> +			if (pmu->type == type)
> +				return true;
> +		}
> +	}
> +	return false;
> +}
> +
>  static inline int output_type(unsigned int type)
>  {
>  	switch (type) {
> @@ -394,6 +407,9 @@ static inline int output_type(unsigned int type)
>  			return type;
>  	}
>  
> +	if (output_type_many_core_pmus(type))
> +		return PERF_TYPE_RAW;
> +
>  	return OUTPUT_TYPE_OTHER;
>  }

Can you please test the patch below so that we don't do this while loop
in all calls to output_type when we have more than one core pmu?

I haven't tested this patch, so please see if your patch on top of it
produces the desired result.

- Arnaldo