[PATCH 11/37] perf tools: Introduce thread__comm_time() helpers

[Namhyung Kim]

When multi-file data storage is enabled, it processes all task, comm
and mmap events first and then goes to the sample events.  So all it
sees is the last comm of a thread although it has information at the
time of sample.

Sort thread's comm by time so that it can find appropriate comm at the
sample time.  The thread__comm_time() will mostly work even if
PERF_SAMPLE_TIME bit is off since in that case, sample->time will be
-1 so it'll take the last comm anyway.

Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
 tools/perf/util/thread.c | 34 +++++++++++++++++++++++++++++++++-
 tools/perf/util/thread.h |  2 ++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 9ebc8b1f9be5..083fa0fcf316 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -103,6 +103,22 @@ struct comm *thread__exec_comm(const struct thread *thread)
 	return last;
 }
 
+struct comm *thread__comm_time(const struct thread *thread, u64 timestamp)
+{
+	struct comm *comm;
+
+	list_for_each_entry(comm, &thread->comm_list, list) {
+		if (timestamp >= comm->start)
+			return comm;
+	}
+
+	if (list_empty(&thread->comm_list))
+		return NULL;
+
+	return list_last_entry(&thread->comm_list, struct comm, list);
+}
+
+/* CHECKME: time should always be 0 if event aren't ordered */
 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 		       bool exec)
 {
@@ -118,7 +134,13 @@ int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
 		new = comm__new(str, timestamp, exec);
 		if (!new)
 			return -ENOMEM;
-		list_add(&new->list, &thread->comm_list);
+
+		/* sort by time */
+		list_for_each_entry(curr, &thread->comm_list, list) {
+			if (timestamp >= curr->start)
+				break;
+		}
+		list_add_tail(&new->list, &curr->list);
 
 		if (exec)
 			unwind__flush_access(thread);
@@ -139,6 +161,16 @@ const char *thread__comm_str(const struct thread *thread)
 	return comm__str(comm);
 }
 
+const char *thread__comm_time_str(const struct thread *thread, u64 timestamp)
+{
+	const struct comm *comm = thread__comm_time(thread, timestamp);
+
+	if (!comm)
+		return NULL;
+
+	return comm__str(comm);
+}
+
 /* CHECKME: it should probably better return the max comm len from its comm list */
 int thread__comm_len(struct thread *thread)
 {
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 160fd066a7d1..0b6dcd70bc8b 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -53,7 +53,9 @@ static inline int thread__set_comm(struct thread *thread, const char *comm,
 int thread__comm_len(struct thread *thread);
 struct comm *thread__comm(const struct thread *thread);
 struct comm *thread__exec_comm(const struct thread *thread);
+struct comm *thread__comm_time(const struct thread *thread, u64 timestamp);
 const char *thread__comm_str(const struct thread *thread);
+const char *thread__comm_time_str(const struct thread *thread, u64 timestamp);
 void thread__insert_map(struct thread *thread, struct map *map);
 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp);
 size_t thread__fprintf(struct thread *thread, FILE *fp);
-- 
2.1.3

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