From 73d0b93829de0432902d264cd907ddf6f0d70cb1 Mon Sep 17 00:00:00 2001
From: Alessio Morale <alessiomorale@gmail.com>
Date: Sat, 22 Feb 2014 00:29:02 +0100
Subject: [PATCH] OP-1026 Add a task monitor api to calculate idle percentage

---
 flight/pios/common/pios_task_monitor.c | 32 ++++++++++++++++++++++++--
 flight/pios/inc/pios_task_monitor.h    |  6 +++++
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/flight/pios/common/pios_task_monitor.c b/flight/pios/common/pios_task_monitor.c
index 7a3c13234..e4a1aceb5 100644
--- a/flight/pios/common/pios_task_monitor.c
+++ b/flight/pios/common/pios_task_monitor.c
@@ -33,6 +33,7 @@
 static xSemaphoreHandle mLock;
 static xTaskHandle *mTaskHandles;
 static uint32_t mLastMonitorTime;
+static uint32_t mLastIdleMonitorTime;
 static uint16_t mMaxTasks;
 
 /**
@@ -53,9 +54,11 @@ int32_t PIOS_TASK_MONITOR_Initialize(uint16_t max_tasks)
 
     mMaxTasks = max_tasks;
 #if (configGENERATE_RUN_TIME_STATS == 1)
-    mLastMonitorTime = portGET_RUN_TIME_COUNTER_VALUE();
+    mLastMonitorTime     = portGET_RUN_TIME_COUNTER_VALUE();
+    mLastIdleMonitorTime = portGET_RUN_TIME_COUNTER_VALUE();
 #else
-    mLastMonitorTime = 0;
+    mLastMonitorTime     = 0;
+    mLastIdleMonitorTime = 0;
 #endif
     return 0;
 }
@@ -146,4 +149,29 @@ void PIOS_TASK_MONITOR_ForEachTask(TaskMonitorTaskInfoCallback callback, void *c
     xSemaphoreGiveRecursive(mLock);
 }
 
+uint8_t PIOS_TASK_MONITOR_GetIdlePercentage()
+{
+#if defined(ARCH_POSIX) || defined(ARCH_WIN32)
+    return 50;
+
+#elif (configGENERATE_RUN_TIME_STATS == 1)
+    xSemaphoreTakeRecursive(mLock, portMAX_DELAY);
+
+    uint32_t currentTime = portGET_RUN_TIME_COUNTER_VALUE();
+
+    /* avoid divide-by-zero if the interval is too small */
+    uint32_t deltaTime   = ((currentTime - mLastIdleMonitorTime) / 100) ? : 1;
+    mLastIdleMonitorTime = currentTime;
+    uint8_t running_time_percentage = 0;
+
+    /* Generate idle time percentage stats */
+    running_time_percentage = uxTaskGetRunTime(xTaskGetIdleTaskHandle()) / deltaTime;
+    xSemaphoreGiveRecursive(mLock);
+    return running_time_percentage;
+
+#endif
+    return 0;
+}
+
+
 #endif // PIOS_INCLUDE_TASK_MONITOR
diff --git a/flight/pios/inc/pios_task_monitor.h b/flight/pios/inc/pios_task_monitor.h
index ed3d1d519..b888cf637 100644
--- a/flight/pios/inc/pios_task_monitor.h
+++ b/flight/pios/inc/pios_task_monitor.h
@@ -104,4 +104,10 @@ typedef void (*TaskMonitorTaskInfoCallback)(uint16_t task_id, const struct pios_
  */
 extern void PIOS_TASK_MONITOR_ForEachTask(TaskMonitorTaskInfoCallback callback, void *context);
 
+/**
+ * Return the idle task running time percentage.
+ */
+
+extern uint8_t PIOS_TASK_MONITOR_GetIdlePercentage();
+
 #endif // PIOS_TASK_MONITOR_H