[PATCH v4 0/2] perf stat: Add interval-count and time support

[ufo19890607 <ufo19890607@gmail.com>]

From: yuzhoujian <yuzhoujian@didichuxing.com>

Introduce two new options for perf stat and update perf-stat documentation
accordingly.

The interval-count option can be used to print counts for fixed number of
times, and it should be used specifically with "-I" option.

Show below is the output of the interval-count option for perf stat.

        $ perf stat -I 1000 --interval-count 2 -e cycles -a
        #           time             counts unit events
             1.002827089         93,884,870      cycles
             2.004231506         56,573,446      cycles
    
The time option can be used to print counts after a period of time, and it
should not be used with "-I" option.

Show below is the output of the time option for perf stat.

        $ perf stat --time 2000 -e cycles -a
        Performance counter stats for 'system wide':

                157,260,423      cycles

                2.003060766 seconds time elapsed

yuzhoujian (2):
  perf stat: Add support to print counts for fixed times
  perf stat: Add support to print counts after a period of time

Changes since v3: 
- merge interval_count check and times check to one line.
- fix the wrong indent in stat.h
- use stat_config.times instead of 'times' in cmd_stat function.

Changes since v2: 
- modify the time check in __run_perf_stat func to keep some consistency
  with the workload case.
- add the warning when the time is set between 10ms to 100ms.
- add the pr_err when the time is set below 10ms.

Changes since v1:
- change the name of the new option "times-print" to "interval-count".
- keep the interval-count option interval specifically.


 tools/perf/Documentation/perf-stat.txt | 10 +++++++
 tools/perf/builtin-stat.c              | 53 ++++++++++++++++++++++++++++++++--
 tools/perf/util/stat.h                 |  2 ++
 3 files changed, 62 insertions(+), 3 deletions(-)

-- 
2.14.1