[PATCH v2] perf test workload: Add thread count argument to thloop

[Ian Rogers <irogers@google.com>]

Allow the number of threads for the thloop workload to be increased
beyond the normal 2. Add error checking to the parsed time and thread
count values.

Signed-off-by: Ian Rogers <irogers@google.com>
---
v2: Perform the pthread_join unconditionally and ensure started
    threads terminate.
---
 tools/perf/tests/workloads/thloop.c | 45 ++++++++++++++++++++++++-----
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/tools/perf/tests/workloads/thloop.c b/tools/perf/tests/workloads/thloop.c
index 457b29f91c3e..bd8168f883fb 100644
--- a/tools/perf/tests/workloads/thloop.c
+++ b/tools/perf/tests/workloads/thloop.c
@@ -31,21 +31,52 @@ static void *thfunc(void *arg)
 
 static int thloop(int argc, const char **argv)
 {
-	int sec = 1;
-	pthread_t th;
+	int nt = 2, sec = 1, err = 1;
+	pthread_t *thread_list = NULL;
 
 	if (argc > 0)
 		sec = atoi(argv[0]);
 
+	if (sec <= 0) {
+		fprintf(stderr, "Error: seconds (%d) must be >= 1\n", sec);
+		return 1;
+	}
+
+	if (argc > 1)
+		nt = atoi(argv[1]);
+
+	if (nt <= 0) {
+		fprintf(stderr, "Error: thread count (%d) must be >= 1\n", nt);
+		return 1;
+	}
+
 	signal(SIGINT, sighandler);
 	signal(SIGALRM, sighandler);
-	alarm(sec);
 
-	pthread_create(&th, NULL, thfunc, test_loop);
-	test_loop();
-	pthread_join(th, NULL);
+	thread_list = calloc(nt, sizeof(pthread_t));
+	if (thread_list == NULL) {
+		fprintf(stderr, "Error: malloc failed for %d threads\n", nt);
+		goto out;
+	}
+	for (int i = 1; i < nt; i++) {
+		int ret = pthread_create(&thread_list[i], NULL, thfunc, test_loop);
 
-	return 0;
+		if (ret) {
+			fprintf(stderr, "Error: failed to create thread %d\n", i);
+			done = 1; // Ensure started threads terminate.
+			goto out;
+		}
+	}
+	alarm(sec);
+	test_loop();
+	err = 0;
+out:
+	for (int i = 1; i < nt; i++) {
+		if (thread_list && thread_list[i])
+			pthread_join(thread_list[i], /*retval=*/NULL);
+	}
+	free(thread_list);
+	return err;
 }
 
 DEFINE_WORKLOAD(thloop);
-- 
2.51.1.851.g4ebd6896fd-goog