UTY-1376: added metric send system (#13)

Author: paulbalaji

CHANGELOG.md

@@ -2,7 +2,12 @@
 
 ## Unreleased
 
+### Added
+
+- Added a metric sending system for load, FPS and Unity heap usage.
+
 ### Fixed
+
 - Fixed an issue with the default snapshot that prevented the player lifecycle module from spawning a player.
 
 ## `0.1.2` - 2018-11-02

workers/unity/Assets/Scripts/MetricSendSystem.cs

@@ -0,0 +1,85 @@
+using System;
+using Improbable.Gdk.Core;
+using Improbable.Worker;
+using Improbable.Worker.Core;
+using Unity.Entities;
+using UnityEngine;
+
+namespace BlankProject
+{
+    public class MetricSendSystem : ComponentSystem
+    {
+        private Connection connection;
+
+        private DateTime timeOfNextUpdate;
+        private DateTime timeOfLastUpdate;
+
+        private const double TimeBetweenMetricUpdatesSecs = 2;
+        private const int DefaultTargetFrameRate = 60;
+
+        private double targetFps;
+
+        private int lastFrameCount;
+        private double calculatedFps;
+
+        // We use exponential smoothing for the FPS metric
+        // larger value == more smoothing, 0 = no smoothing
+        // 0 <= smoothing < 1
+        private const double smoothing = 0;
+
+        private static readonly Metrics WorkerMetrics = new Metrics();
+
+        protected override void OnCreateManager()
+        {
+            base.OnCreateManager();
+            connection = World.GetExistingManager<WorkerSystem>().Connection;
+
+            targetFps = Application.targetFrameRate == -1
+                ? DefaultTargetFrameRate
+                : Application.targetFrameRate;
+
+            lastFrameCount = Time.frameCount;
+            calculatedFps = targetFps;
+
+            timeOfLastUpdate = DateTime.Now;
+            timeOfNextUpdate = timeOfLastUpdate.AddSeconds(TimeBetweenMetricUpdatesSecs);
+        }
+
+        protected override void OnUpdate()
+        {
+            if (connection == null)
+            {
+                return;
+            }
+
+            if (DateTime.Now >= timeOfNextUpdate)
+            {
+                CalculateFps();
+                WorkerMetrics.GaugeMetrics["Dynamic.FPS"] = calculatedFps;
+                WorkerMetrics.GaugeMetrics["Unity used heap size"] = GC.GetTotalMemory(false);
+                WorkerMetrics.Load = CalculateLoad();
+
+                connection.SendMetrics(WorkerMetrics);
+
+                timeOfLastUpdate = DateTime.Now;
+                timeOfNextUpdate = timeOfLastUpdate.AddSeconds(TimeBetweenMetricUpdatesSecs);
+            }
+        }
+
+        // Load defined as performance relative to target FPS.
+        // i.e. a load of 0.5 means that the worker is hitting the target FPS
+        // but achieving less than half the target FPS takes load above 1.0
+        private double CalculateLoad()
+        {
+            return Math.Max(0.0d, 0.5d * targetFps / calculatedFps);
+        }
+
+        private void CalculateFps()
+        {
+            var frameCount = Time.frameCount - lastFrameCount;
+            lastFrameCount = Time.frameCount;
+            var rawFps = frameCount / (DateTime.Now - timeOfLastUpdate).TotalSeconds;
+            calculatedFps = (rawFps * (1 - smoothing)) + (calculatedFps * smoothing);
+        }
+    }
+}

workers/unity/Assets/Scripts/MetricSendSystem.cs.meta

@@ -20,6 +20,7 @@ private async void Start()
 
         protected override void HandleWorkerConnectionEstablished()
         {
+            Worker.World.GetOrCreateManager<MetricSendSystem>();
             PlayerLifecycleHelper.AddServerSystems(Worker.World);
         }