linux-kernel - Re: [PATCH v4 14/25] perf stat: Add default hybrid events

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Date:   Thu, 22 Apr 2021 10:12:49 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v4 14/25] perf stat: Add default hybrid events

Hi Jiri,

On 4/22/2021 2:29 AM, Jiri Olsa wrote:
> On Fri, Apr 16, 2021 at 10:05:06PM +0800, Jin Yao wrote:
> 
> SNIP
> 
>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>> index 1255af4751c2..0351b99d17a7 100644
>> --- a/tools/perf/builtin-stat.c
>> +++ b/tools/perf/builtin-stat.c
>> @@ -1145,6 +1145,13 @@ static int parse_stat_cgroups(const struct option *opt,
>>   	return parse_cgroups(opt, str, unset);
>>   }
>>   
>> +static int add_default_hybrid_events(struct evlist *evlist)
>> +{
>> +	struct parse_events_error err;
>> +
>> +	return parse_events(evlist, "cycles,instructions,branches,branch-misses", &err);
>> +}
>> +
>>   static struct option stat_options[] = {
>>   	OPT_BOOLEAN('T', "transaction", &transaction_run,
>>   		    "hardware transaction statistics"),
>> @@ -1626,6 +1633,12 @@ static int add_default_attributes(void)
>>     { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS	},
>>     { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES		},
>>   
>> +};
>> +	struct perf_event_attr default_sw_attrs[] = {
>> +  { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK		},
>> +  { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES	},
>> +  { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS		},
>> +  { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS		},
> 
> hum, why not use default_attrs0, it's the same, no?
> 

The default_attrs0 has one more item " {.type = PERF_TYPE_HARDWARE, .config = 
PERF_COUNT_HW_CPU_CYCLES },"

So I have to only pick out the sw attrs and save them to default_sw_attrs.

>>   };
>>   
>>   /*
>> @@ -1863,6 +1876,14 @@ static int add_default_attributes(void)
>>   	}
>>   
>>   	if (!evsel_list->core.nr_entries) {
>> +		if (perf_pmu__has_hybrid()) {
>> +			if (evlist__add_default_attrs(evsel_list,
>> +						      default_sw_attrs) < 0) {
>> +				return -1;
>> +			}
>> +			return add_default_hybrid_events(evsel_list);
> 
> please do it the same way like when topdown calls parse events,
> we don't need to check for cycles, but please check result and
> display the error
> 

Something like this?

err = parse_events(evsel_list, "cycles,instructions,branches,branch-misses", &errinfo);
if (err) {
	fprintf(stderr,...);
	parse_events_print_error(&errinfo, ...);
	return -1;
}

> 
>> +		}
>> +
>>   		if (target__has_cpu(&target))
>>   			default_attrs0[0].config = PERF_COUNT_SW_CPU_CLOCK;
> 
> also you still want this change for hybrid pmus as well
> 

Yes, the default_sw_attr only uses 'PERF_COUNT_SW_TASK_CLOCK', we do need to change it to 
PERF_COUNT_SW_CPU_CLOCK for system wide.

> thanks,
> jirka
>

Thanks
Jin Yao

>>   
>> -- 
>> 2.17.1
>>
>