linux-kernel - Re: [PATCH v1 8/9] perf stat: Remove --per-thread pid/tid limitation

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Date:   Wed, 22 Nov 2017 13:38:53 +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 v1 8/9] perf stat: Remove --per-thread pid/tid limitation



On 11/21/2017 11:18 PM, Jiri Olsa wrote:
> On Mon, Nov 20, 2017 at 10:43:43PM +0800, Jin Yao wrote:
>> Currently, if we execute 'perf stat --per-thread' without specifying
>> pid/tid, perf will return error.
>>
>> root@skl:/tmp# perf stat --per-thread
>> The --per-thread option is only available when monitoring via -p -t options.
>>      -p, --pid <pid>       stat events on existing process id
>>      -t, --tid <tid>       stat events on existing thread id
>>
>> This patch removes this limitation. If no pid/tid specified, it returns
>> all threads (get threads from /proc).
>>
>> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
>> ---
>>   tools/perf/builtin-stat.c | 23 +++++++++++++++--------
>>   tools/perf/util/target.h  |  7 +++++++
>>   2 files changed, 22 insertions(+), 8 deletions(-)
>>
>> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
>> index 9eec145..2d718f7 100644
>> --- a/tools/perf/builtin-stat.c
>> +++ b/tools/perf/builtin-stat.c
>> @@ -277,7 +277,7 @@ static int create_perf_stat_counter(struct perf_evsel *evsel)
>>   			attr->enable_on_exec = 1;
>>   	}
>>   
>> -	if (target__has_cpu(&target))
>> +	if (target__has_cpu(&target) && !target__has_per_thread(&target))
> 
> please add comment on why this is needed..
> 
>>   		return perf_evsel__open_per_cpu(evsel, perf_evsel__cpus(evsel));
>>   
>>   	return perf_evsel__open_per_thread(evsel, evsel_list->threads);
>> @@ -340,7 +340,7 @@ static int read_counter(struct perf_evsel *counter)
>>   	int nthreads = thread_map__nr(evsel_list->threads);
>>   	int ncpus, cpu, thread;
>>   
>> -	if (target__has_cpu(&target))
>> +	if (target__has_cpu(&target) && !target__has_per_thread(&target))
> 
> same here
> 

That's because this patch series doesn't support cpu_list yet. So if 
it's a cpu_list case, then skip.

I plan to add cpu_list supporting as follow-up patch to avoid adding too 
much in this patch series.

Thanks
Jin Yao

> thanks,
> jirka
>