perf evlist: Add evlist__add_dummy_on_all_cpus()

Add evlist__add_dummy_on_all_cpus() to enable creating a system-wide dummy
event that sets up the system-wide maps before map propagation.

For convenience, add evlist__add_aux_dummy() so that the logic can be used
whether or not the event needs to be system-wide.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Link: https://lore.kernel.org/r/20220524075436.29144-6-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index efad0e6..48af7d3 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -264,6 +264,51 @@ int evlist__add_dummy(struct evlist *evlist)
        return 0;
 }
 
+static void evlist__add_on_all_cpus(struct evlist *evlist, struct evsel *evsel)
+{
+       evsel->core.system_wide = true;
+
+       /*
+        * All CPUs.
+        *
+        * Note perf_event_open() does not accept CPUs that are not online, so
+        * in fact this CPU list will include only all online CPUs.
+        */
+       perf_cpu_map__put(evsel->core.own_cpus);
+       evsel->core.own_cpus = perf_cpu_map__new(NULL);
+       perf_cpu_map__put(evsel->core.cpus);
+       evsel->core.cpus = perf_cpu_map__get(evsel->core.own_cpus);
+
+       /* No threads */
+       perf_thread_map__put(evsel->core.threads);
+       evsel->core.threads = perf_thread_map__new_dummy();
+
+       evlist__add(evlist, evsel);
+}
+
+struct evsel *evlist__add_aux_dummy(struct evlist *evlist, bool system_wide)
+{
+       struct evsel *evsel = evlist__dummy_event(evlist);
+
+       if (!evsel)
+               return NULL;
+
+       evsel->core.attr.exclude_kernel = 1;
+       evsel->core.attr.exclude_guest = 1;
+       evsel->core.attr.exclude_hv = 1;
+       evsel->core.attr.freq = 0;
+       evsel->core.attr.sample_period = 1;
+       evsel->no_aux_samples = true;
+       evsel->name = strdup("dummy:u");
+
+       if (system_wide)
+               evlist__add_on_all_cpus(evlist, evsel);
+       else
+               evlist__add(evlist, evsel);
+
+       return evsel;
+}
+
 static int evlist__add_attrs(struct evlist *evlist, struct perf_event_attr *attrs, size_t nr_attrs)
 {
        struct evsel *evsel, *n;

diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 4062f5a..1bde9cc 100644 (file)
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -114,6 +114,11 @@ int arch_evlist__add_default_attrs(struct evlist *evlist);
 struct evsel *arch_evlist__leader(struct list_head *list);
 
 int evlist__add_dummy(struct evlist *evlist);
+struct evsel *evlist__add_aux_dummy(struct evlist *evlist, bool system_wide);
+static inline struct evsel *evlist__add_dummy_on_all_cpus(struct evlist *evlist)
+{
+       return evlist__add_aux_dummy(evlist, true);
+}
 
 int evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,
                         evsel__sb_cb_t cb, void *data);