Consolidate relative sched_get_priority computation

2 files changed, 29 insertions, 27 deletions

diff --git a/libs/pbd/pbd/pthread_utils.h b/libs/pbd/pbd/pthread_utils.h
index e917fa27ce..f223d1c22e 100644
--- a/libs/pbd/pbd/pthread_utils.h
+++ b/libs/pbd/pbd/pthread_utils.h
@@ -60,6 +60,7 @@ LIBPBD_API int pbd_realtime_pthread_create (
 		void *(*start_routine) (void *),
 		void *arg);
 
+LIBPBD_API int  pbd_absolute_rt_priority (int policy, int priority);
 LIBPBD_API int  pbd_set_thread_priority (pthread_t, const int policy, int priority);
 LIBPBD_API bool pbd_mach_set_realtime_policy (pthread_t thread_id, double period_ns);
 
diff --git a/libs/pbd/pthread_utils.cc b/libs/pbd/pthread_utils.cc
index 118c54b97f..64ac8bb563 100644
--- a/libs/pbd/pthread_utils.cc
+++ b/libs/pbd/pthread_utils.cc
@@ -209,6 +209,32 @@ pthread_cancel_one (pthread_t thread)
 }
 
 int
+pbd_absolute_rt_priority (int policy, int priority)
+{
+	/* POSIX requires a spread of at least 32 steps between min..max */
+	const int p_min = sched_get_priority_min (policy); // Linux: 1
+	const int p_max = sched_get_priority_max (policy); // Linux: 99
+
+	if (priority == 0) {
+		/* use default. XXX this should be relative to audio (JACK) thread,
+		 * internal backends use -20 (Audio), -21 (MIDI), -22 (compuation)
+		 */
+		priority = 7; // BaseUI backwards compat.
+	}
+
+	if (priority > 0) {
+		priority += p_min;
+	} else {
+		priority += p_max;
+	}
+	if (priority > p_max) priority = p_max;
+	if (priority < p_min) priority = p_min;
+	return priority;
+}
+
+
+
+int
 pbd_realtime_pthread_create (
 		const int policy, int priority, const size_t stacksize,
 		pthread_t *thread,
@@ -220,12 +246,7 @@ pbd_realtime_pthread_create (
 	pthread_attr_t attr;
 	struct sched_param parm;
 
-	const int p_min = sched_get_priority_min (policy);
-	const int p_max = sched_get_priority_max (policy);
-	priority += p_max;
-	if (priority > p_max) priority = p_max;
-	if (priority < p_min) priority = p_min;
-	parm.sched_priority = priority;
+	parm.sched_priority = pbd_absolute_rt_priority (policy, priority);
 
 	pthread_attr_init (&attr);
 	pthread_attr_setschedpolicy (&attr, policy);
@@ -237,32 +258,12 @@ pbd_realtime_pthread_create (
 	pthread_attr_destroy (&attr);
 	return rv;
 }
-
 int
 pbd_set_thread_priority (pthread_t thread, const int policy, int priority)
 {
 	struct sched_param param;
 	memset (&param, 0, sizeof (param));
-
-	/* POSIX requires a spread of at least 32 steps between min..max */
-	const int p_min = sched_get_priority_min (policy); // Linux: 1
-	const int p_max = sched_get_priority_max (policy); // Linux: 99
-
-	if (priority == 0) {
-		/* use default. XXX this should be relative to audio (JACK) thread,
-		 * internal backends use -20 (Audio), -21 (MIDI), -22 (compuation)
-		 */
-		priority = 7; // BaseUI backwards compat.
-	}
-
-	if (priority > 0) {
-		priority += p_min;
-	} else {
-		priority += p_max;
-	}
-	if (priority > p_max) priority = p_max;
-	if (priority < p_min) priority = p_min;
-	param.sched_priority = priority;
+	param.sched_priority = pbd_absolute_rt_priority (policy, priority);
 
 	return pthread_setschedparam (thread, SCHED_FIFO, &param);
 }