fix: more stable profiler stats. Averages over a full second. No memory allocations. (#692)

Co-authored-by: M. Fatih MAR <[email protected]>

Author: jeffreyrainy

com.unity.multiplayer.mlapi/Runtime/Profiling/ProfilerStat.cs

@@ -1,14 +1,7 @@
-using System.Collections.Generic;
 using UnityEngine;
 
 namespace MLAPI.Profiling
 {
-    public struct Sample
-    {
-        public int Count;
-        public float TimeRecorded;
-    }
-
     public class ProfilerStat
     {
         public ProfilerStat(string name)
@@ -18,67 +11,28 @@ public ProfilerStat(string name)
         }
 
         public string PrettyPrintName;
-        protected int m_MaxSamples = 10;
-
-        protected LinkedList<Sample> m_Data = new LinkedList<Sample>();
-
-        private bool m_IsDirty = true;
 
-        protected float m_LastCount;
-        protected float m_LastTime;
+        private int m_CurrentSecond = 0;
+        private int m_TotalAmount = 0;
+        private int m_Sample = 0;
 
         public virtual void Record(int amt = 1)
         {
-            m_IsDirty = true;
-            var timeNow = Time.time;
-            // 'Record' can get called many times in the same frame (for the same exact timestamp)
-            //   This not only blows out the samples but makes the rate computation break since we 
-            //   have n samples with a time delta of zero.
-            // 
-            //   Instead, if we want to record a value at the same exact time as our last
-            //   sample, just adjust that sample
-            if (m_Data.First != null && m_Data.First.Value.TimeRecorded == timeNow)
+            int currentSecond = (int)Time.unscaledTime;
+            if (currentSecond != m_CurrentSecond)
             {
-                m_Data.First.Value = new Sample()
-                {
-                    Count = m_Data.First.Value.Count + amt,
-                    TimeRecorded = m_Data.First.Value.TimeRecorded
-                };
-            }
-            else
-            {
-                m_Data.AddFirst(new Sample() { Count = amt, TimeRecorded = Time.time });
-                while (m_Data.Count > m_MaxSamples)
-                {
-                    m_Data.RemoveLast();
-                }
+                m_Sample = m_TotalAmount;
+
+                m_TotalAmount = 0;
+                m_CurrentSecond = currentSecond;
             }
+
+            m_TotalAmount += amt;
         }
 
         public virtual float SampleRate()
         {
-            if (m_IsDirty)
-            {
-                LinkedListNode<Sample> node = m_Data.First;
-                m_LastCount = 0;
-                m_LastTime = m_Data.Last?.Value.TimeRecorded ?? 0.0f;
-
-                while (node != null)
-                {
-                    m_LastCount += node.Value.Count;
-                    node = node.Next;
-                }
-
-                m_IsDirty = false;
-            }
-
-            float delta = Time.time - m_LastTime;
-            if (delta == 0.0f)
-            {
-                return 0.0f;
-            }
-
-            return m_LastCount / delta;
+            return m_Sample;
         }
     }
 
@@ -90,12 +44,6 @@ public ProfilerIncStat(string name) : base(name) { }
 
         public override void Record(int amt = 1)
         {
-            m_Data.AddFirst(new Sample() { Count = amt, TimeRecorded = Time.time });
-            while (m_Data.Count > m_MaxSamples)
-            {
-                m_Data.RemoveLast();
-            }
-
             m_InternalValue += amt;
         }