Re: [PATCH] perf stat: Create '--add-default' option to append default list

Jin, Yao Tue, 22 Dec 2020 16:59:45 -0800

Hi Arnaldo,

On 12/23/2020 12:15 AM, Arnaldo Carvalho de Melo wrote:

Em Tue, Dec 22, 2020 at 09:11:31AM +0800, Jin Yao escreveu:

The event default 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.


It's better to add a new option to append default list to the -e events.
The new option is '--add-default'.

Before:

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

  Performance counter stats for 'system wide':

               2.05 Joules power/energy-pkg/

        1.000857974 seconds time elapsed

After:

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


I thought about:

     perf stat -e +power/energy-pkg/ -a -- sleep 1


I was surprised to see that '+<event>' syntax had been supported.

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

 Performance counter stats for 'system wide':

              1.99 Joules +power/energy-pkg/

       1.000877852 seconds time elapsed

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

 Performance counter stats for 'system wide':

              2.00 Joules +power/energy-pkg/
        13,780,620        +cycles

       1.001639147 seconds time elapsed

Are there any scripts or usages need the prefix '+' before event? I don't know. But if we append the'+<event>' to the default event list, will break something potentially?

Which would have its counterpart:

     perf stat -e -cycles -0a --sleep 1

To remove an event from the defaults, perhaps to deal with some specific
hardware where the default or what is in -d, -dd, -ddd, etc can't all be
counted. I.e. - and + would remove or add from whaver list was there at
that point.

- Arnaldo

Yes, + and - are more flexible solution. Just for above question, will '+<event>' break existingusage? And for '-', I don't know if user can remember clearly for what the events are in default list.


Thanks
Jin Yao

  Performance counter stats for 'system wide':

               2.10 Joules power/energy-pkg/         #    0.000 K/sec
           8,009.89 msec   cpu-clock                 #    7.995 CPUs utilized
                140        context-switches          #    0.017 K/sec
                  9        cpu-migrations            #    0.001 K/sec
                 66        page-faults               #    0.008 K/sec
         10,671,929        cycles                    #    0.001 GHz
          4,736,880        instructions              #    0.44  insn per cycle
            942,951        branches                  #    0.118 M/sec
             76,096        branch-misses             #    8.07% of all branches

        1.001809960 seconds time elapsed

Signed-off-by: Jin Yao <yao....@linux.intel.com>
---
  tools/perf/Documentation/perf-stat.txt | 5 +++++
  tools/perf/builtin-stat.c              | 4 +++-
  tools/perf/util/stat.h                 | 1 +
  3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-stat.txt 
b/tools/perf/Documentation/perf-stat.txt
index 5d4a673d7621..75a83c2e4dc5 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -438,6 +438,11 @@ convenient for post processing.
  --summary::
  Print summary for interval mode (-I).

+--add-default::

+The default event list includes the most common events which are widely
+used by users. But with -e option, the perf only counts the events assigned
+by -e option. This options appends the default event list to the -e events.
+
  EXAMPLES
  --------

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c

index 89c32692f40c..6ac7b946f9a7 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -1173,6 +1173,8 @@ static struct option stat_options[] = {
                       "print summary for interval mode"),
        OPT_BOOLEAN(0, "quiet", &stat_config.quiet,
                        "don't print output (useful with record)"),
+       OPT_BOOLEAN(0, "add-default", &stat_config.add_default,
+                      "add default events"),
  #ifdef HAVE_LIBPFM
        OPT_CALLBACK(0, "pfm-events", &evsel_list, "event",
                "libpfm4 event selector. use 'perf list' to list available 
events",
@@ -1755,7 +1757,7 @@ static int add_default_attributes(void)
                free(str);
        }

- if (!evsel_list->core.nr_entries) {

+       if (!evsel_list->core.nr_entries || stat_config.add_default) {
                if (target__has_cpu(&target))
                        default_attrs0[0].config = PERF_COUNT_SW_CPU_CLOCK;

diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h

index 9979b4b100f2..6ccc6936348c 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -123,6 +123,7 @@ struct perf_stat_config {
        bool                     metric_no_merge;
        bool                     stop_read_counter;
        bool                     quiet;
+       bool                     add_default;
        FILE                    *output;
        unsigned int             interval;
        unsigned int             timeout;
--
2.17.1

Re: [PATCH] perf stat: Create '--add-default' option to append default list

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