[PATCH] libperf: Add API for allocating new thread map

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

The existing API perf_thread_map__new_dummy() allocates new thread map
for one thread. I couldn't find a way to reallocate the map with more
threads, or to allocate a new map for more than one thread. Having
multiple threads in a thread map is essential for some use cases.
That's why a new API is proposed, which allocates a new thread map
for given number of threads:
 perf_thread_map__new()

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 tools/lib/perf/Documentation/libperf.txt |  1 +
 tools/lib/perf/include/perf/threadmap.h  |  1 +
 tools/lib/perf/libperf.map               |  1 +
 tools/lib/perf/tests/test-threadmap.c    | 27 ++++++++++++++++++++++++
 tools/lib/perf/threadmap.c               | 15 +++++++++----
 5 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index 32c5051c24eb..9cbd41c29bff 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -62,6 +62,7 @@ SYNOPSIS
   struct perf_thread_map;
 
   struct perf_thread_map *perf_thread_map__new_dummy(void);
+  struct perf_thread_map *perf_thread_map__new(int nr);
 
   void perf_thread_map__set_pid(struct perf_thread_map *map, int thread, pid_t pid);
   char *perf_thread_map__comm(struct perf_thread_map *map, int thread);
diff --git a/tools/lib/perf/include/perf/threadmap.h b/tools/lib/perf/include/perf/threadmap.h
index a7c50de8d010..47d433416040 100644
--- a/tools/lib/perf/include/perf/threadmap.h
+++ b/tools/lib/perf/include/perf/threadmap.h
@@ -8,6 +8,7 @@
 struct perf_thread_map;
 
 LIBPERF_API struct perf_thread_map *perf_thread_map__new_dummy(void);
+LIBPERF_API struct perf_thread_map *perf_thread_map__new(int nr);
 
 LIBPERF_API void perf_thread_map__set_pid(struct perf_thread_map *map, int thread, pid_t pid);
 LIBPERF_API char *perf_thread_map__comm(struct perf_thread_map *map, int thread);
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 93696affda2e..240a2f087b70 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -11,6 +11,7 @@ LIBPERF_0.0.1 {
 		perf_cpu_map__empty;
 		perf_cpu_map__max;
 		perf_cpu_map__has;
+		perf_thread_map__new;
 		perf_thread_map__new_dummy;
 		perf_thread_map__set_pid;
 		perf_thread_map__comm;
diff --git a/tools/lib/perf/tests/test-threadmap.c b/tools/lib/perf/tests/test-threadmap.c
index 5e2a0291e94c..3388bf36dfc0 100644
--- a/tools/lib/perf/tests/test-threadmap.c
+++ b/tools/lib/perf/tests/test-threadmap.c
@@ -11,9 +11,12 @@ static int libperf_print(enum libperf_print_level level,
 	return vfprintf(stderr, fmt, ap);
 }
 
+#define THREADS_NR	5
+
 int test_threadmap(int argc, char **argv)
 {
 	struct perf_thread_map *threads;
+	int i;
 
 	__T_START;
 
@@ -27,6 +30,30 @@ int test_threadmap(int argc, char **argv)
 	perf_thread_map__put(threads);
 	perf_thread_map__put(threads);
 
+	threads = perf_thread_map__new(THREADS_NR);
+	if (!threads)
+		tests_failed++;
+
+	if (perf_thread_map__nr(threads) != THREADS_NR)
+		tests_failed++;
+
+	for (i = 0; i < THREADS_NR; i++) {
+		if (perf_thread_map__pid(threads, i) != -1)
+			tests_failed++;
+	}
+
+	for (i = 1; i < THREADS_NR; i++)
+		perf_thread_map__set_pid(threads, i, i * 100);
+
+	if (perf_thread_map__pid(threads, 0) != -1)
+		tests_failed++;
+
+	for (i = 1; i < THREADS_NR; i++) {
+		if (perf_thread_map__pid(threads, i) != i * 100)
+			tests_failed++;
+	}
+	perf_thread_map__put(threads);
+
 	__T_END;
 	return tests_failed == 0 ? 0 : -1;
 }
diff --git a/tools/lib/perf/threadmap.c b/tools/lib/perf/threadmap.c
index e92c368b0a6c..843fe1070cc9 100644
--- a/tools/lib/perf/threadmap.c
+++ b/tools/lib/perf/threadmap.c
@@ -42,18 +42,25 @@ char *perf_thread_map__comm(struct perf_thread_map *map, int thread)
 	return map->map[thread].comm;
 }
 
-struct perf_thread_map *perf_thread_map__new_dummy(void)
+struct perf_thread_map *perf_thread_map__new(int nr)
 {
-	struct perf_thread_map *threads = thread_map__alloc(1);
+	struct perf_thread_map *threads = thread_map__alloc(nr);
+	int i;
 
 	if (threads != NULL) {
-		perf_thread_map__set_pid(threads, 0, -1);
-		threads->nr = 1;
+		for (i = 0; i < nr; i++)
+			perf_thread_map__set_pid(threads, i, -1);
+		threads->nr = nr;
 		refcount_set(&threads->refcnt, 1);
 	}
 	return threads;
 }
 
+struct perf_thread_map *perf_thread_map__new_dummy(void)
+{
+	return perf_thread_map__new(1);
+}
+
 static void perf_thread_map__delete(struct perf_thread_map *threads)
 {
 	if (threads) {
-- 
2.34.1