1 files changed, 64 insertions, 13 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 42ea4e9..c7d111f 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -302,6 +302,24 @@ static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 {
 	u64 read_data[4] = { 0, };
 	int id_idx = 1; /* The first entry is the counter value */
+	u64 id;
+	int ret;
+
+	ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
+	if (!ret)
+		goto add;
+
+	if (errno != ENOTTY)
+		return -1;
+
+	/* Legacy way to get event id.. All hail to old kernels! */
+
+	/*
+	 * This way does not work with group format read, so bail
+	 * out in that case.
+	 */
+	if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
+		return -1;
 
 	if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
 	    read(fd, &read_data, sizeof(read_data)) == -1)
@@ -312,25 +330,39 @@ static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
 		++id_idx;
 
-	perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
+	id = read_data[id_idx];
+
+ add:
+	perf_evlist__id_add(evlist, evsel, cpu, thread, id);
 	return 0;
 }
 
-struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
+struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id)
 {
 	struct hlist_head *head;
 	struct perf_sample_id *sid;
 	int hash;
 
-	if (evlist->nr_entries == 1)
-		return perf_evlist__first(evlist);
-
 	hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
 	head = &evlist->heads[hash];
 
 	hlist_for_each_entry(sid, head, node)
 		if (sid->id == id)
-			return sid->evsel;
+			return sid;
+
+	return NULL;
+}
+
+struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
+{
+	struct perf_sample_id *sid;
+
+	if (evlist->nr_entries == 1)
+		return perf_evlist__first(evlist);
+
+	sid = perf_evlist__id2sid(evlist, id);
+	if (sid)
+		return sid->evsel;
 
 	if (!perf_evlist__sample_id_all(evlist))
 		return perf_evlist__first(evlist);
@@ -662,6 +694,32 @@ u64 perf_evlist__sample_type(struct perf_evlist *evlist)
 	return first->attr.sample_type;
 }
 
+bool perf_evlist__valid_read_format(struct perf_evlist *evlist)
+{
+	struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
+	u64 read_format = first->attr.read_format;
+	u64 sample_type = first->attr.sample_type;
+
+	list_for_each_entry_continue(pos, &evlist->entries, node) {
+		if (read_format != pos->attr.read_format)
+			return false;
+	}
+
+	/* PERF_SAMPLE_READ imples PERF_FORMAT_ID. */
+	if ((sample_type & PERF_SAMPLE_READ) &&
+	    !(read_format & PERF_FORMAT_ID)) {
+		return false;
+	}
+
+	return true;
+}
+
+u64 perf_evlist__read_format(struct perf_evlist *evlist)
+{
+	struct perf_evsel *first = perf_evlist__first(evlist);
+	return first->attr.read_format;
+}
+
 u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist)
 {
 	struct perf_evsel *first = perf_evlist__first(evlist);
@@ -779,13 +837,6 @@ int perf_evlist__prepare_workload(struct perf_evlist *evlist,
 		fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
 
 		/*
-		 * Do a dummy execvp to get the PLT entry resolved,
-		 * so we avoid the resolver overhead on the real
-		 * execvp call.
-		 */
-		execvp("", (char **)argv);
-
-		/*
 		 * Tell the parent we're ready to go
 		 */
 		close(child_ready_pipe[1]);