[PATCH 28/37] perf evsel: Introduce method to request IDs be used

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

When mmaping multiple events we need to find the right evsel that
matches an event in the ring buffer.

For that we need to set the PERF_FORMAT_ID bit in
perf_event_attr.read_format so that when we read the event fds we get
that id to then hash it and be able later to use perf_evlist__id2evsel
to find the right evsel.

We also need to set the PERF_SAMPLE_ID bit in
perf_event_attr.sample_type to ask for that id to be stashed in each
sample, so that we can demux it.

So add a perf_evsel__set_sample_id() method to do those two things in
one operation.

Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-1z4xcmbud30lamklfe80oopu@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-top.c      |    6 ++----
 tools/perf/tests/mmap-basic.c |    3 +--
 tools/perf/util/evsel.c       |    6 ++++++
 tools/perf/util/evsel.h       |    2 ++
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 31a7c51..a306474 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -910,10 +910,8 @@ static void perf_top__start_counters(struct perf_top *top)
 			attr->sample_freq = top->freq;
 		}
 
-		if (evlist->nr_entries > 1) {
-			perf_evsel__set_sample_bit(counter, ID);
-			attr->read_format |= PERF_FORMAT_ID;
-		}
+		if (evlist->nr_entries > 1)
+			perf_evsel__set_sample_id(counter);
 
 		if (perf_target__has_cpu(&top->target))
 			perf_evsel__set_sample_bit(counter, CPU);
diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index 4743b6d..cdd5075 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -70,8 +70,7 @@ int test__basic_mmap(void)
 		}
 
 		evsels[i]->attr.wakeup_events = 1;
-		evsels[i]->attr.read_format |= PERF_FORMAT_ID;
-		perf_evsel__set_sample_bit(evsels[i], ID);
+		perf_evsel__set_sample_id(evsels[i]);
 
 		perf_evlist__add(evlist, evsels[i]);
 
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index fc80f5a..9dde7e9 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -68,6 +68,12 @@ void __perf_evsel__reset_sample_bit(struct perf_evsel *evsel,
 	}
 }
 
+void perf_evsel__set_sample_id(struct perf_evsel *evsel)
+{
+	perf_evsel__set_sample_bit(evsel, ID);
+	evsel->attr.read_format |= PERF_FORMAT_ID;
+}
+
 void perf_evsel__init(struct perf_evsel *evsel,
 		      struct perf_event_attr *attr, int idx)
 {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 7398539..5c08977 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -129,6 +129,8 @@ void __perf_evsel__reset_sample_bit(struct perf_evsel *evsel,
 #define perf_evsel__reset_sample_bit(evsel, bit) \
 	__perf_evsel__reset_sample_bit(evsel, PERF_SAMPLE_##bit)
 
+void perf_evsel__set_sample_id(struct perf_evsel *evsel);
+
 int perf_evsel__set_filter(struct perf_evsel *evsel, int ncpus, int nthreads,
 			   const char *filter);
 
-- 
1.7.9.2.358.g22243

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/