Go back to the FIFO scheduler for now, as we don't have time to shake out the RR scheduler changeover just yet.

Make the "default" scheduler a centralized definition so that changes are easier in future.

apps/ardrone_interface/ardrone_interface.c

@@ -115,7 +115,7 @@ int ardrone_interface_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		ardrone_interface_task = task_spawn("ardrone_interface",
-						    SCHED_RR,
+						    SCHED_DEFAULT,
 						    SCHED_PRIORITY_MAX - 15,
 						    4096,
 						    ardrone_interface_thread_main,

apps/attitude_estimator_ekf/attitude_estimator_ekf_main.c

@@ -159,7 +159,7 @@ int attitude_estimator_ekf_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		attitude_estimator_ekf_task = task_spawn("attitude_estimator_ekf",
-							 SCHED_RR,
+							 SCHED_DEFAULT,
 							 SCHED_PRIORITY_MAX - 5,
 							 20000,
 							 attitude_estimator_ekf_thread_main,

apps/commander/commander.c

@@ -950,7 +950,7 @@ int commander_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		deamon_task = task_spawn("commander",
-					 SCHED_RR,
+					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_MAX - 50,
 					 4096,
 					 commander_thread_main,

apps/examples/px4_deamon_app/px4_deamon_app.c

@@ -92,7 +92,7 @@ int px4_deamon_app_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		deamon_task = task_spawn("deamon",
-					 SCHED_RR,
+					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_DEFAULT,
 					 4096,
 					 px4_deamon_thread_main,

apps/fixedwing_control/fixedwing_control.c

@@ -416,7 +416,7 @@ int fixedwing_control_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		deamon_task = task_spawn("fixedwing_control",
-					 SCHED_RR,
+					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_MAX - 20,
 					 4096,
 					 fixedwing_control_thread_main,

apps/gps/gps.c

@@ -143,7 +143,7 @@ int gps_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		deamon_task = task_spawn("gps",
-					 SCHED_RR,
+					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_DEFAULT,
 					 4096,
 					 gps_thread_main,

apps/mavlink/mavlink.c

@@ -1872,7 +1872,7 @@ int mavlink_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		mavlink_task = task_spawn("mavlink",
-					  SCHED_RR,
+					  SCHED_DEFAULT,
 					  SCHED_PRIORITY_DEFAULT,
 					  6000,
 					  mavlink_thread_main,

apps/multirotor_att_control/multirotor_att_control_main.c

@@ -353,7 +353,7 @@ int multirotor_att_control_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		mc_task = task_spawn("multirotor_att_control",
-				     SCHED_RR,
+				     SCHED_DEFAULT,
 				     SCHED_PRIORITY_MAX - 15,
 				     4096,
 				     mc_thread_main,

apps/px4/fmu/fmu.cpp

@@ -172,7 +172,7 @@ FMUServo::init()
 
 	/* start the IO interface task */
 	_task = task_spawn("fmuservo",
-			   SCHED_RR,
+			   SCHED_DEFAULT,
 			   SCHED_PRIORITY_DEFAULT,
 			   1024,
 			   (main_t)&FMUServo::task_main_trampoline,

apps/sdlog/sdlog.c

@@ -109,7 +109,7 @@ usage(const char *reason)
  * Makefile does only apply to this management task.
  * 
  * The actual stack size should be set in the call
- * to task_create().
+ * to task_spawn().
  */
 int sdlog_main(int argc, char *argv[])
 {
@@ -126,7 +126,7 @@ int sdlog_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		deamon_task = task_spawn("sdlog",
-					 SCHED_RR,
+					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_DEFAULT - 30,
 					 4096,
 					 sdlog_thread_main,

apps/sensors/sensors.cpp

@@ -1174,7 +1174,7 @@ Sensors::start()
 
 	/* start the task */
 	_sensors_task = task_spawn("sensors_task",
-				   SCHED_RR,
+				   SCHED_DEFAULT,
 				   SCHED_PRIORITY_MAX - 5,
 				   6000,	/* XXX may be excesssive */
 				   (main_t)&Sensors::task_main_trampoline,

apps/systemcmds/led/led.c

@@ -148,7 +148,7 @@ int led_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		led_task = task_spawn("led",
-				      SCHED_RR,
+				      SCHED_DEFAULT,
 				      SCHED_PRIORITY_MAX - 15,
 				      4096,
 				      led_thread_main,

apps/systemlib/systemlib.c

@@ -138,9 +138,8 @@ int task_spawn(const char *name, int scheduler, int priority, int stack_size, ma
 		param.sched_priority = priority;
 		sched_setscheduler(pid, scheduler, &param);
 
-		/* XXX do any other private task accounting here */
+		/* XXX do any other private task accounting here before the task starts */
 	}
-
 	sched_unlock();
 
 	return pid;

apps/systemlib/systemlib.h

@@ -50,6 +50,13 @@ __EXPORT int reboot(void);
 /** Sends SIGUSR1 to all processes */
 __EXPORT void killall(void);
 
+/** Default scheduler type */
+#if CONFIG_RR_INTERVAL > 0
+# define SCHED_DEFAULT	SCHED_RR
+#else
+# define SCHED_DEFAULT	SCHED_FIFO
+#endif
+
 /** Starts a task and performs any specific accounting, scheduler setup, etc. */
 __EXPORT int task_spawn(const char *name,
 			int priority,

nuttx/configs/px4fmu/nsh/defconfig

@@ -546,7 +546,7 @@ CONFIG_HAVE_CXXINITIALIZE=n
 CONFIG_MM_REGIONS=2
 CONFIG_ARCH_LOWPUTC=y
 CONFIG_MSEC_PER_TICK=1
-CONFIG_RR_INTERVAL=1
+CONFIG_RR_INTERVAL=0
 CONFIG_SCHED_INSTRUMENTATION=y
 CONFIG_TASK_NAME_SIZE=24
 CONFIG_START_YEAR=1970