Merge remote-tracking branch 'upstream/master' into ros

Conflicts:
	src/platforms/px4_middleware.h

src/modules/systemlib/perf_counter.h

@@ -57,7 +57,7 @@ typedef struct perf_ctr_header	*perf_counter_t;
 __BEGIN_DECLS
 
 /**
- * Create a new counter.
+ * Create a new local counter.
  *
  * @param type			The type of the new counter.
  * @param name			The counter name.
@@ -66,6 +66,16 @@ __BEGIN_DECLS
  */
 __EXPORT extern perf_counter_t	perf_alloc(enum perf_counter_type type, const char *name);
 
+/**
+ * Get the reference to an existing counter or create a new one if it does not exist.
+ *
+ * @param type			The type of the counter.
+ * @param name			The counter name.
+ * @return			Handle for the counter, or NULL if a counter
+ *				could not be allocated.
+ */
+__EXPORT extern perf_counter_t	perf_alloc_once(enum perf_counter_type type, const char *name);
+
 /**
  * Free a counter.
  *
@@ -102,6 +112,18 @@ __EXPORT extern void		perf_begin(perf_counter_t handle);
  */
 __EXPORT extern void		perf_end(perf_counter_t handle);
 
+/**
+ * Register a measurement
+ *
+ * This call applies to counters that operate over ranges of time; PC_ELAPSED etc.
+ * If a call is made without a corresponding perf_begin call. It sets the
+ * value provided as argument as a new measurement.
+ *
+ * @param handle		The handle returned from perf_alloc.
+ * @param elapsed		The time elapsed. Negative values lead to incrementing the overrun counter.
+ */
+__EXPORT extern void		perf_set(perf_counter_t handle, int64_t elapsed);
+
 /**
  * Cancel a performance event.
  *