perf evsel: Introduce method to request IDs be used

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@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-1z4xcmbud30lamklfe80oopu@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 31a7c51aac7635476992fc01892d8a6719c847ce..a30647487ba394f2ddfeed226a845764dafb65b6 100644 (file)
--- 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 4743b6d7a09ad959b9dd90a10493e2023b4c7e4b..cdd50755af51d6155e1fcf875965ae5576fe70d1 100644 (file)
--- 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 fc80f5a32fa60a7bd4ae366771ad8cb6b2cb018c..9dde7e933be94a44a2e9328cd379475db21b1aea 100644 (file)
--- 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 7398539692439156e86a26f5e4025b1d318e2108..5c089775064f7f9ff69a43225334c26aa6b8a489 100644 (file)
--- 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);