perf evlist: Introduce add_tracepoints method

Convenient way of asking for tracepoint events to be added to an
existing evlist.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
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-0ylj4wrg54791u0baqb9swbb@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 56 insertions, 1 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 58aa1e0092bd..3bc5a287a9f9 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -6,12 +6,13 @@
  *
  * Released under the GPL v2. (and only v2, not any later version)
  */
+#include "util.h"
+#include "debugfs.h"
 #include <poll.h>
 #include "cpumap.h"
 #include "thread_map.h"
 #include "evlist.h"
 #include "evsel.h"
-#include "util.h"
 
 #include "parse-events.h"
 
@@ -134,6 +135,60 @@ out_delete_partial_list:
         return -1;
 }
 
+static int trace_event__id(const char *evname)
+{
+        char *filename, *colon;
+        int err = -1, fd;
+
+        if (asprintf(&filename, "%s/%s/id", tracing_events_path, evname) < 0)
+                return -1;
+
+        colon = strrchr(filename, ':');
+        if (colon != NULL)
+                *colon = '/';
+
+        fd = open(filename, O_RDONLY);
+        if (fd >= 0) {
+                char id[16];
+                if (read(fd, id, sizeof(id)) > 0)
+                        err = atoi(id);
+                close(fd);
+        }
+
+        free(filename);
+        return err;
+}
+
+int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
+                                 const char *tracepoints[],
+                                 size_t nr_tracepoints)
+{
+        int err;
+        size_t i;
+        struct perf_event_attr *attrs = zalloc(nr_tracepoints * sizeof(*attrs));
+
+        if (attrs == NULL)
+                return -1;
+
+        for (i = 0; i < nr_tracepoints; i++) {
+                err = trace_event__id(tracepoints[i]);
+
+                if (err < 0)
+                        goto out_free_attrs;
+
+                attrs[i].type          = PERF_TYPE_TRACEPOINT;
+                attrs[i].config        = err;
+                attrs[i].sample_type   = (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |
+                                          PERF_SAMPLE_CPU);
+                attrs[i].sample_period = 1;
+        }
+
+        err = perf_evlist__add_attrs(evlist, attrs, nr_tracepoints);
+out_free_attrs:
+        free(attrs);
+        return err;
+}
+
 void perf_evlist__disable(struct perf_evlist *evlist)
 {
         int cpu, thread;