Re: [PATCH v2] perf stat: Append to default list if use -e +event

["Jin, Yao" <yao.jin@linux.intel.com>]

Hi Jiri,

On 1/12/2021 6:08 PM, Jiri Olsa wrote:
> On Mon, Jan 04, 2021 at 10:18:37AM +0800, Jin Yao wrote:
>> The default event list includes the most common events which are widely
>> used by users. But with -e option, the current perf only counts the events
>> assigned by -e option. Users may want to collect some extra events with
>> the default list. For this case, users have to manually add all the events
>> from the default list. It's inconvenient. Also, users may don't know how to
>> get the default list.
>>
>> Now it supports a simple syntax: -e +event
>>
>> The prefix '+' tells perf to append this event (or event list) to default
>> event list.
>>
>> Before:
>>
>> root@kbl-ppc:~# ./perf stat -e power/energy-pkg/ -a -- sleep 1
>>
>>   Performance counter stats for 'system wide':
>>
>>                2.04 Joules power/energy-pkg/
>>
>>         1.000863884 seconds time elapsed
>>
>> After:
>>
>> root@kbl-ppc:~# ./perf stat -e +power/energy-pkg/ -a -- sleep 1
>>
>>   Performance counter stats for 'system wide':
>>
>>                2.11 Joules +power/energy-pkg/        #    0.000 K/sec
> 
> I dont think we should print the extra '+' prefix
> 
> jirka
> 
>>            8,007.17 msec   cpu-clock                 #    7.993 CPUs utilized
>>                 125        context-switches          #    0.016 K/sec
>>                   8        cpu-migrations            #    0.001 K/sec
>>                   2        page-faults               #    0.000 K/sec
>>           8,520,084        cycles                    #    0.001 GHz
>>           2,808,302        instructions              #    0.33  insn per cycle
>>             555,427        branches                  #    0.069 M/sec
>>              59,005        branch-misses             #   10.62% of all branches
>>
>>         1.001832003 seconds time elapsed
>>
>> Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
> 

Printing '+' prefix is the original behavior.

Without this patch,

root@kbl-ppc:# ./perf stat -e +power/energy-pkg/ -a -- sleep 1

  Performance counter stats for 'system wide':

               2.02 Joules +power/energy-pkg/

        1.000859434 seconds time elapsed

The '+' prefix is printed. So I finally decide not to remove the '+' prefix in order to keep 
original behavior.

Thanks
Jin Yao