linux-kernel - Re: [PATCH 1/5] perf stat: add perf stat -B to pretty print large numbers

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Date:	Mon, 31 May 2010 21:30:36 +0200
From:	Stephane Eranian <eranian@...gle.com>
To:	Valdis.Kletnieks@...edu
Cc:	Arnaldo Carvalho de Melo <acme@...radead.org>,
	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Tom Zanussi <tzanussi@...il.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: Re: [PATCH 1/5] perf stat: add perf stat -B to pretty print large 
	numbers

On Mon, May 31, 2010 at 9:11 PM,  <Valdis.Kletnieks@...edu> wrote:
> On Tue, 18 May 2010 23:08:16 -0300, Arnaldo Carvalho de Melo said:
>
> (Sorry for late reply)
>
>> instance LC_NUMERIC=en_US.UTF8. You need to pass -B to activate this
>> feature. This way existing scripts parsing the output do not need to be
>> changed. Here is an example.
>>
>> $ perf stat noploop 2
>> noploop for 2 seconds
>>
>>  Performance counter stats for 'noploop 2':
>>
>>         1998.347031  task-clock-msecs         #      0.998 CPUs
>>                  61  context-switches         #      0.000 M/sec
>>                   0  CPU-migrations           #      0.000 M/sec
>>                 118  page-faults              #      0.000 M/sec
>>       4,138,410,900  cycles                   #   2070.917 M/sec  (scaled from 70.01%)
>>       2,062,650,268  instructions             #      0.498 IPC    (scaled from 70.01%)
>>       2,057,653,466  branches                 #   1029.678 M/sec  (scaled from 70.01%)
>>              40,267  branch-misses            #      0.002 %      (scaled from 30.04%)
>>       2,055,961,348  cache-references         #   1028.831 M/sec  (scaled from 30.03%)
>>              53,725  cache-misses             #      0.027 M/sec  (scaled from 30.02%)
>>
>>         2.001393933  seconds time elapsed
>>
>> $ perf stat -B  noploop 2
>> noploop for 2 seconds
>>
>>  Performance counter stats for 'noploop 2':
>>
>>         1998.297883  task-clock-msecs         #      0.998 CPUs
>>                  59  context-switches         #      0.000 M/sec
>>                   0  CPU-migrations           #      0.000 M/sec
>>                 119  page-faults              #      0.000 M/sec
>>       4,131,380,160  cycles                   #   2067.450 M/sec  (scaled from 70.01%)
>>       2,059,096,507  instructions             #      0.498 IPC    (scaled from 70.01%)
>>       2,054,681,303  branches                 #   1028.216 M/sec  (scaled from 70.01%)
>>              25,650  branch-misses            #      0.001 %      (scaled from 30.05%)
>>       2,056,283,014  cache-references         #   1029.017 M/sec  (scaled from 30.03%)
>>              47,097  cache-misses             #      0.024 M/sec  (scaled from 30.02%)
>>
>>         2.001391016  seconds time elapsed
>
> Is it me, or did -B not make any difference for these two examples?
> I'm confused.
>
Did you set the LC_NUMERIC environement variable?

>> -     fprintf(stderr, " %14.6f  %-24s", msecs, event_name(counter));
>> +     fprintf(stderr, " %18.6f  %-24s", msecs, event_name(counter));
>
>> -     fprintf(stderr, " %14.0f  %-24s", avg, event_name(counter));
>> +     if (big_num)
>> +             fprintf(stderr, " %'18.0f  %-24s", avg, event_name(counter));
>> +     else
>> +             fprintf(stderr, " %18.0f  %-24s", avg, event_name(counter));
>
>> -             fprintf(stderr, " %14s  %-24s\n",
>> +             fprintf(stderr, " %18s  %-24s\n",
>>                       "<not counted>", event_name(counter));
>
>> -     fprintf(stderr, " %14.9f  seconds time elapsed",
>> +     fprintf(stderr, " %18.9f  seconds time elapsed",
>
> Why is the 'if (big_num)' applied to only one of the 4 sites, and the
> other 3 blindly expanded from 14 to 18 characters?

Because the units of the others don't make sense.
The expansion is to make things still appear aligned when the thousands
are separated.

>



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