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

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Message-ID: <66df2821-80a4-4ec2-b326-d0edda8fcde2@linux.intel.com>
Date: Fri, 13 Dec 2024 13:34:07 -0500
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Ravi Bangoria <ravi.bangoria@....com>,
 Thomas Falcon <thomas.falcon@...el.com>
Cc: linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
 peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
 namhyung@...nel.org, mark.rutland@....com,
 alexander.shishkin@...ux.intel.com, jolsa@...nel.org, irogers@...gle.com,
 adrian.hunter@...el.com
Subject: Re: [PATCH] perf script: Fix output type for dynamically allocated
 core PMU's



On 2024-12-13 2:07 a.m., Ravi Bangoria wrote:
> Hi Thomas,
> 
>> @@ -386,6 +386,8 @@ static int evsel_script__fprintf(struct evsel_script *es, FILE *fp)
>>  
>>  static inline int output_type(unsigned int type)
>>  {
>> +	struct perf_pmu *pmu;
>> +
>>  	switch (type) {
>>  	case PERF_TYPE_SYNTH:
>>  		return OUTPUT_TYPE_SYNTH;
>> @@ -394,6 +396,10 @@ static inline int output_type(unsigned int type)
>>  			return type;
>>  	}
>>  
>> +	pmu = perf_pmus__find_by_type(type);
>> +	if (pmu && pmu->is_core)
>> +		return PERF_TYPE_RAW;
> 
> Minor nit ...
> 
> output_type() seems to be getting called a lot. For ex, for a perf.data
> with 4530 samples, output_type() was called 181246 times when I ran
> "perf script". IIUC, this pmu lookup is unnecessary for homogeneous
> platforms? If so, can we make it conditional?
> 

Agreed. I think the search should only be applied for the
perf_pmus__num_core_pmus() > 1 case.

We should just need to search the core_pmus when comparing the type.

Thanks,
Kan