perf evsel: No need to always ask for PERF_FORMAT_ID in read_format

Instead make perf_evlist__confir_attrs use perf_evsel__set_sample_id()
when having more than one event, that way only if we have multiple
events we'll ask to have the event ids returned when we read its file
descriptors.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-xuho5hrrxy2ky0cjpr80hyfp@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/attr/base-record

@@ -7,7 +7,7 @@ size=96
 config=0
 sample_period=4000
 sample_type=263
-read_format=7
+read_format=3
 disabled=1
 inherit=1
 pinned=0

tools/perf/tests/attr/test-record-group

@@ -6,12 +6,14 @@ args    = --group -e cycles,instructions kill >/dev/null 2>&1
 fd=1
 group_fd=-1
 sample_type=327
+read_format=7
 
 [event-2:base-record]
 fd=2
 group_fd=1
 config=1
 sample_type=327
+read_format=7
 mmap=0
 comm=0
 enable_on_exec=0

tools/perf/tests/attr/test-record-group1

@@ -6,6 +6,7 @@ args    = -e '{cycles,instructions}' kill >/tmp/krava 2>&1
 fd=1
 group_fd=-1
 sample_type=327
+read_format=7
 
 [event-2:base-record]
 fd=2
@@ -13,6 +14,7 @@ group_fd=1
 type=0
 config=1
 sample_type=327
+read_format=7
 mmap=0
 comm=0
 enable_on_exec=0

tools/perf/util/evlist.c

@@ -61,7 +61,7 @@ void perf_evlist__config_attrs(struct perf_evlist *evlist,
 		perf_evsel__config(evsel, opts);
 
 		if (evlist->nr_entries > 1)
-			perf_evsel__set_sample_bit(evsel, ID);
+			perf_evsel__set_sample_id(evsel);
 	}
 }
 

tools/perf/util/evsel.c

@@ -466,8 +466,7 @@ void perf_evsel__config(struct perf_evsel *evsel,
 	attr->sample_id_all = opts->sample_id_all_missing ? 0 : 1;
 	attr->inherit	    = !opts->no_inherit;
 	attr->read_format   = PERF_FORMAT_TOTAL_TIME_ENABLED |
-			      PERF_FORMAT_TOTAL_TIME_RUNNING |
-			      PERF_FORMAT_ID;
+			      PERF_FORMAT_TOTAL_TIME_RUNNING;
 
 	perf_evsel__set_sample_bit(evsel, IP);
 	perf_evsel__set_sample_bit(evsel, TID);