From b2ee7647ee05604397672f6b7c1a804b07466270 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Thu, 23 Oct 2014 09:15:20 -0600
Subject: [PATCH] Start and stop status interval (or file) thread separately

This gets rid of the need to create threads on the fly for this,
and we can manage it and stop it before we do real stats at
the end.

Signed-off-by: Jens Axboe <axboe@fb.com>
---
 backend.c |  2 ++
 stat.c    | 80 +++++++++++++++++++++++++++++++++++--------------------
 stat.h    |  2 ++
 3 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/backend.c b/backend.c
index 14803c38..4437d196 100644
--- a/backend.c
+++ b/backend.c
@@ -2073,6 +2073,7 @@ int fio_backend(void)
 	set_genesis_time();
 	stat_init();
 	create_disk_util_thread();
+	create_status_interval_thread();
 
 	cgroup_list = smalloc(sizeof(*cgroup_list));
 	INIT_FLIST_HEAD(cgroup_list);
@@ -2080,6 +2081,7 @@ int fio_backend(void)
 	run_threads();
 
 	wait_for_disk_thread_exit();
+	wait_for_status_interval_thread_exit();
 
 	if (!fio_abort) {
 		__show_run_stats();
diff --git a/stat.c b/stat.c
index 03dc4588..a5fd50b9 100644
--- a/stat.c
+++ b/stat.c
@@ -1422,7 +1422,7 @@ void show_run_stats(void)
 	fio_mutex_up(stat_mutex);
 }
 
-static void *__show_running_run_stats(void *arg)
+static void __show_running_run_stats(void)
 {
 	struct thread_data *td;
 	unsigned long long *rt;
@@ -1471,34 +1471,6 @@ static void *__show_running_run_stats(void *arg)
 
 	free(rt);
 	fio_mutex_up(stat_mutex);
-	free(arg);
-	return NULL;
-}
-
-/*
- * Called from signal handler. It _should_ be safe to just run this inline
- * in the sig handler, but we should be disturbing the system less by just
- * creating a thread to do it.
- */
-void show_running_run_stats(void)
-{
-	pthread_t *thread;
-
-	thread = calloc(1, sizeof(*thread));
-	if (!thread)
-		return;
-
-	if (!pthread_create(thread, NULL, __show_running_run_stats, thread)) {
-		int err;
-
-		err = pthread_detach(*thread);
-		if (err)
-			log_err("fio: DU thread detach failed: %s\n", strerror(err));
-
-		return;
-	}
-
-	free(thread);
 }
 
 static int status_interval_init;
@@ -1917,3 +1889,53 @@ void stat_exit(void)
 	fio_mutex_down(stat_mutex);
 	fio_mutex_remove(stat_mutex);
 }
+
+static pthread_t si_thread;
+static pthread_cond_t si_cond;
+static pthread_mutex_t si_lock;
+static int si_thread_exit;
+
+/*
+ * Called from signal handler. Wake up status thread.
+ */
+void show_running_run_stats(void)
+{
+	pthread_cond_signal(&si_cond);
+}
+
+static void *si_thread_main(void *unused)
+{
+	while (!si_thread_exit) {
+		pthread_cond_wait(&si_cond, &si_lock);
+		if (si_thread_exit)
+			break;
+
+		__show_running_run_stats();
+	}
+
+	return NULL;
+}
+
+void create_status_interval_thread(void)
+{
+	int ret;
+
+	pthread_cond_init(&si_cond, NULL);
+	pthread_mutex_init(&si_lock, NULL);
+
+	ret = pthread_create(&si_thread, NULL, si_thread_main, NULL);
+	if (ret) {
+		log_err("Can't create status thread: %s\n", strerror(ret));
+		return;
+	}
+}
+
+void wait_for_status_interval_thread_exit(void)
+{
+	void *ret;
+
+	si_thread_exit = 1;
+	pthread_cond_signal(&si_cond);
+	pthread_join(si_thread, &ret);
+	pthread_cond_destroy(&si_cond);
+}
diff --git a/stat.h b/stat.h
index d834cffc..2c68edcc 100644
--- a/stat.h
+++ b/stat.h
@@ -234,6 +234,8 @@ extern void stat_calc_lat_m(struct thread_stat *ts, double *io_u_lat);
 extern void stat_calc_lat_u(struct thread_stat *ts, double *io_u_lat);
 extern void stat_calc_dist(unsigned int *map, unsigned long total, double *io_u_dist);
 extern void reset_io_stats(struct thread_data *);
+extern void create_status_interval_thread(void);
+extern void wait_for_status_interval_thread_exit(void);
 
 static inline int usec_to_msec(unsigned long *min, unsigned long *max,
 			       double *mean, double *dev)
-- 
2.25.1