[tip:perf/core] perf report: Add an indication of what time slices are used

[tip-bot for Jin Yao]

Commit-ID:  7425664bbd3174814500c7ab8740cbb9bb25396c
Gitweb:     https://git.kernel.org/tip/7425664bbd3174814500c7ab8740cbb9bb25396c
Author:     Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 10 Jan 2018 23:00:30 +0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 17 Jan 2018 10:23:36 -0300

perf report: Add an indication of what time slices are used

Add a time slices indication to the perf report header.

For example,

  # perf report --stdio --time 10%

  # Total Lost Samples: 0
  #
  # Samples: 9K of event 'cycles:ppp' (time slices: 10%)
  # Event count (approx.): 8951288803

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Suggested--by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1515596433-24653-6-git-send-email-yao.jin@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-report.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 7d4f0a5..4aaaa37 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -404,6 +404,9 @@ static size_t hists__fprintf_nr_sample_events(struct hists *hists, struct report
 	if (evname != NULL)
 		ret += fprintf(fp, " of event '%s'", evname);
 
+	if (rep->time_str)
+		ret += fprintf(fp, " (time slices: %s)", rep->time_str);
+
 	if (symbol_conf.show_ref_callgraph &&
 	    strstr(evname, "call-graph=no")) {
 		ret += fprintf(fp, ", show reference callgraph");