Added documentation for all performance counter methods and members. Refactored the naming of several members and methods to reflect their actual intention.

11 files changed, 276 insertions, 210 deletions

diff --git a/src/SMAPI.Mods.ConsoleCommands/Framework/Commands/Other/PerformanceCounterCommand.cs b/src/SMAPI.Mods.ConsoleCommands/Framework/Commands/Other/PerformanceCounterCommand.cs
index 84b9504e..750e3792 100644
--- a/src/SMAPI.Mods.ConsoleCommands/Framework/Commands/Other/PerformanceCounterCommand.cs
+++ b/src/SMAPI.Mods.ConsoleCommands/Framework/Commands/Other/PerformanceCounterCommand.cs
@@ -134,8 +134,8 @@ namespace StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands.Other
                 {
                     if (sourceName == null)
                     {
-                        collection.Monitor = true;
-                        collection.MonitorThresholdMilliseconds = threshold;
+                        collection.EnableAlerts = true;
+                        collection.AlertThresholdMilliseconds = threshold;
                         monitor.Log($"Set up monitor for '{collectionName}' with '{this.FormatMilliseconds(threshold)}'", LogLevel.Info);
                         return;
                     }
@@ -145,8 +145,8 @@ namespace StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands.Other
                         {
                             if (performanceCounter.Value.Source.ToLowerInvariant().Equals(sourceName.ToLowerInvariant()))
                             {
-                                performanceCounter.Value.Monitor = true;
-                                performanceCounter.Value.MonitorThresholdMilliseconds = threshold;
+                                performanceCounter.Value.EnableAlerts = true;
+                                performanceCounter.Value.AlertThresholdMilliseconds = threshold;
                                 monitor.Log($"Set up monitor for '{sourceName}' in collection '{collectionName}' with '{this.FormatMilliseconds(threshold)}", LogLevel.Info);
                                 return;
                             }
@@ -167,17 +167,17 @@ namespace StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands.Other
             int clearedCounters = 0;
             foreach (PerformanceCounterCollection collection in SCore.PerformanceCounterManager.PerformanceCounterCollections)
             {
-                if (collection.Monitor)
+                if (collection.EnableAlerts)
                 {
-                    collection.Monitor = false;
+                    collection.EnableAlerts = false;
                     clearedCounters++;
                 }
 
                 foreach (var performanceCounter in collection.PerformanceCounters)
                 {
-                    if (performanceCounter.Value.Monitor)
+                    if (performanceCounter.Value.EnableAlerts)
                     {
-                        performanceCounter.Value.Monitor = false;
+                        performanceCounter.Value.EnableAlerts = false;
                         clearedCounters++;
                     }
                 }
@@ -197,14 +197,14 @@ namespace StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands.Other
 
             foreach (PerformanceCounterCollection collection in SCore.PerformanceCounterManager.PerformanceCounterCollections)
             {
-                if (collection.Monitor)
+                if (collection.EnableAlerts)
                 {
-                    collectionMonitors.Add((collection.Name, collection.MonitorThresholdMilliseconds));
+                    collectionMonitors.Add((collection.Name, collection.AlertThresholdMilliseconds));
                 }
 
                 sourceMonitors.AddRange(from performanceCounter in
-                    collection.PerformanceCounters where performanceCounter.Value.Monitor
-                    select (collection.Name, performanceCounter.Value.Source, performanceCounter.Value.MonitorThresholdMilliseconds));
+                    collection.PerformanceCounters where performanceCounter.Value.EnableAlerts
+                    select (collection.Name, performanceCounter.Value.Source, MonitorThresholdMilliseconds: performanceCounter.Value.AlertThresholdMilliseconds));
             }
 
             if (collectionMonitors.Count > 0)
@@ -377,7 +377,7 @@ namespace StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands.Other
                 switch (type)
                 {
                     case "category":
-                        SCore.PerformanceCounterManager.ResetCategory(name);
+                        SCore.PerformanceCounterManager.ResetCollection(name);
                         monitor.Log($"All performance counters for category {name} are now cleared.", LogLevel.Info);
                         break;
                     case "mod":
@@ -491,8 +491,8 @@ namespace StardewModdingAPI.Mods.ConsoleCommands.Framework.Commands.Other
                 {
                     item.Key,
                     this.FormatMilliseconds(item.Value.GetAverage(averageInterval), thresholdMilliseconds),
-                    this.FormatMilliseconds(item.Value.GetLastEntry()?.Elapsed.TotalMilliseconds),
-                    this.FormatMilliseconds(item.Value.GetPeak()?.Elapsed.TotalMilliseconds)
+                    this.FormatMilliseconds(item.Value.GetLastEntry()?.ElapsedMilliseconds),
+                    this.FormatMilliseconds(item.Value.GetPeak()?.ElapsedMilliseconds)
                 }
             ));
 
diff --git a/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs b/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs
index c4a57a49..63f0a5ed 100644
--- a/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs
@@ -1,14 +1,26 @@
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
-    public struct AlertContext
+    /// <summary>The context for an alert.</summary>
+    internal struct AlertContext
     {
-        public string Source;
-        public double Elapsed;
+        /// <summary>The source which triggered the alert.</summary>
+        public readonly string Source;
 
+        /// <summary>The elapsed milliseconds.</summary>
+        public readonly double Elapsed;
+
+        /// <summary>Creates a new alert context.</summary>
+        /// <param name="source">The source which triggered the alert.</param>
+        /// <param name="elapsed">The elapsed milliseconds.</param>
         public AlertContext(string source, double elapsed)
         {
             this.Source = source;
             this.Elapsed = elapsed;
         }
+
+        public override string ToString()
+        {
+            return $"{this.Source}: {this.Elapsed:F2}ms";
+        }
     }
 }
diff --git a/src/SMAPI/Framework/PerformanceCounter/AlertEntry.cs b/src/SMAPI/Framework/PerformanceCounter/AlertEntry.cs
index 284af1ce..b87d8642 100644
--- a/src/SMAPI/Framework/PerformanceCounter/AlertEntry.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/AlertEntry.cs
@@ -2,18 +2,31 @@ using System.Collections.Generic;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
+    /// <summary>A single alert entry.</summary>
     internal struct AlertEntry
     {
-        public PerformanceCounterCollection Collection;
-        public double ExecutionTimeMilliseconds;
-        public double Threshold;
-        public List<AlertContext> Context;
+        /// <summary>The collection in which the alert occurred.</summary>
+        public readonly PerformanceCounterCollection Collection;
 
-        public AlertEntry(PerformanceCounterCollection collection, double executionTimeMilliseconds, double threshold, List<AlertContext> context)
+        /// <summary>The actual execution time in milliseconds.</summary>
+        public readonly double ExecutionTimeMilliseconds;
+
+        /// <summary>The configured alert threshold. </summary>
+        public readonly double ThresholdMilliseconds;
+
+        /// <summary>The context list, which records all sources involved in exceeding the threshold.</summary>
+        public readonly List<AlertContext> Context;
+
+        /// <summary>Creates a new alert entry.</summary>
+        /// <param name="collection">The source collection in which the alert occurred.</param>
+        /// <param name="executionTimeMilliseconds">The actual execution time in milliseconds.</param>
+        /// <param name="thresholdMilliseconds">The configured threshold in milliseconds.</param>
+        /// <param name="context">A list of AlertContext to record which sources were involved</param>
+        public AlertEntry(PerformanceCounterCollection collection, double executionTimeMilliseconds, double thresholdMilliseconds, List<AlertContext> context)
         {
             this.Collection = collection;
             this.ExecutionTimeMilliseconds = executionTimeMilliseconds;
-            this.Threshold = threshold;
+            this.ThresholdMilliseconds = thresholdMilliseconds;
             this.Context = context;
         }
     }
diff --git a/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs b/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs
index 1aec28f3..4690c512 100644
--- a/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs
@@ -2,8 +2,13 @@ using StardewModdingAPI.Framework.Events;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
+    /// <summary>Represents a performance counter collection specific to game events.</summary>
     internal class EventPerformanceCounterCollection: PerformanceCounterCollection
     {
+        /// <summary>Creates a new event performance counter collection.</summary>
+        /// <param name="manager">The performance counter manager.</param>
+        /// <param name="event">The ManagedEvent.</param>
+        /// <param name="isImportant">If the event is flagged as important.</param>
         public EventPerformanceCounterCollection(PerformanceCounterManager manager, IManagedEvent @event, bool isImportant) : base(manager, @event.GetName(), isImportant)
         {
         }
diff --git a/src/SMAPI/Framework/PerformanceCounter/IPerformanceCounterEvent.cs b/src/SMAPI/Framework/PerformanceCounter/IPerformanceCounterEvent.cs
deleted file mode 100644
index 1bcf4fa0..00000000
--- a/src/SMAPI/Framework/PerformanceCounter/IPerformanceCounterEvent.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using System;
-using System.Collections.Generic;
-
-namespace StardewModdingAPI.Framework.Utilities
-{
-    public interface IPerformanceCounterEvent
-    {
-        string GetEventName();
-        long GetAverageCallsPerSecond();
-
-        double GetGameAverageExecutionTime();
-        double GetModsAverageExecutionTime();
-        double GetAverageExecutionTime();
-    }
-}
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs
index 3dbc693a..b2ec4c90 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs
@@ -1,26 +1,32 @@
 using System;
-using System.Diagnostics;
 using System.Linq;
 using Cyotek.Collections.Generic;
-using StardewModdingAPI.Framework.Utilities;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
     internal class PerformanceCounter
     {
+        /// <summary>The size of the ring buffer.</summary>
         private const int MAX_ENTRIES = 16384;
 
-        public string Source { get; }
-        public static Stopwatch Stopwatch = new Stopwatch();
-        public static long TotalNumEventsLogged;
-        public double MonitorThresholdMilliseconds { get; set; }
-        public bool Monitor { get; set; }
+        /// <summary>The collection to which this performance counter belongs.</summary>
         private readonly PerformanceCounterCollection ParentCollection;
 
+        /// <summary>The circular buffer which stores all performance counter entries</summary>
         private readonly CircularBuffer<PerformanceCounterEntry> _counter;
 
+        /// <summary>The peak execution time</summary>
         private PerformanceCounterEntry? PeakPerformanceCounterEntry;
 
+        /// <summary>The name of the source.</summary>
+        public string Source { get; }
+
+        /// <summary>The alert threshold in milliseconds</summary>
+        public double AlertThresholdMilliseconds { get; set; }
+
+        /// <summary>If alerting is enabled or not</summary>
+        public bool EnableAlerts { get; set; }
+
         public PerformanceCounter(PerformanceCounterCollection parentCollection, string source)
         {
             this.ParentCollection = parentCollection;
@@ -28,90 +34,87 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
             this._counter = new CircularBuffer<PerformanceCounterEntry>(PerformanceCounter.MAX_ENTRIES);
         }
 
-        public void Reset()
-        {
-            this._counter.Clear();
-            this.PeakPerformanceCounterEntry = null;
-        }
-
-        public int GetAverageCallsPerSecond()
-        {
-            var x = this._counter.GroupBy(
-                p =>
-                    (int) p.EventTime.Subtract(
-                        new DateTime(1970, 1, 1)
-                    ).TotalSeconds);
-
-            return x.Last().Count();
-        }
-
+        /// <summary>Adds a new performance counter entry to the list. Updates the peak entry and adds an alert if
+        /// monitoring is enabled and the execution time exceeds the threshold.</summary>
+        /// <param name="entry">The entry to add.</param>
         public void Add(PerformanceCounterEntry entry)
         {
-            PerformanceCounter.Stopwatch.Start();
             this._counter.Put(entry);
 
-            if (this.Monitor && entry.Elapsed.TotalMilliseconds > this.MonitorThresholdMilliseconds)
-            {
-                this.ParentCollection.AddAlert(entry.Elapsed.TotalMilliseconds, this.MonitorThresholdMilliseconds, new AlertContext(this.Source, entry.Elapsed.TotalMilliseconds));
-            }
+            if (this.EnableAlerts && entry.ElapsedMilliseconds > this.AlertThresholdMilliseconds)
+                this.ParentCollection.AddAlert(entry.ElapsedMilliseconds, this.AlertThresholdMilliseconds,
+                    new AlertContext(this.Source, entry.ElapsedMilliseconds));
 
             if (this.PeakPerformanceCounterEntry == null)
-            {
                 this.PeakPerformanceCounterEntry = entry;
-            }
             else
             {
-                if (entry.Elapsed.TotalMilliseconds > this.PeakPerformanceCounterEntry.Value.Elapsed.TotalMilliseconds)
-                {
+                if (entry.ElapsedMilliseconds > this.PeakPerformanceCounterEntry.Value.ElapsedMilliseconds)
                     this.PeakPerformanceCounterEntry = entry;
-                }
             }
+        }
 
-            PerformanceCounter.Stopwatch.Stop();
-            PerformanceCounter.TotalNumEventsLogged++;
+        /// <summary>Clears all performance counter entries and resets the peak entry.</summary>
+        public void Reset()
+        {
+            this._counter.Clear();
+            this.PeakPerformanceCounterEntry = null;
         }
 
+        /// <summary>Returns the peak entry.</summary>
+        /// <returns>The peak entry.</returns>
         public PerformanceCounterEntry? GetPeak()
         {
             return this.PeakPerformanceCounterEntry;
         }
 
+        /// <summary>Resets the peak entry.</summary>
         public void ResetPeak()
         {
             this.PeakPerformanceCounterEntry = null;
         }
 
+        /// <summary>Returns the last entry added to the list.</summary>
+        /// <returns>The last entry</returns>
         public PerformanceCounterEntry? GetLastEntry()
         {
             if (this._counter.IsEmpty)
-            {
                 return null;
-            }
+
             return this._counter.PeekLast();
         }
 
+        /// <summary>Returns the average execution time of all entries.</summary>
+        /// <returns>The average execution time in milliseconds.</returns>
         public double GetAverage()
         {
             if (this._counter.IsEmpty)
-            {
                 return 0;
-            }
 
-            return this._counter.Average(p => p.Elapsed.TotalMilliseconds);
+            return this._counter.Average(p => p.ElapsedMilliseconds);
         }
 
-        public double GetAverage(TimeSpan range)
+        /// <summary>Returns the average over a given time span.</summary>
+        /// <param name="range">The time range to retrieve.</param>
+        /// <param name="relativeTo">The DateTime from which to start the average. Defaults to DateTime.UtcNow if null</param>
+        /// <returns>The average execution time in milliseconds.</returns>
+        /// <remarks>
+        /// The relativeTo parameter specifies from which point in time the range is subtracted. Example:
+        /// If DateTime is set to 60 seconds ago, and the range is set to 60 seconds, the method would return
+        /// the average between all entries between 120s ago and 60s ago.
+        /// </remarks>
+        public double GetAverage(TimeSpan range, DateTime? relativeTo = null)
         {
             if (this._counter.IsEmpty)
-            {
                 return 0;
-            }
 
-            var lastTime = this._counter.Max(x => x.EventTime);
-            var start = lastTime.Subtract(range);
+            if (relativeTo == null)
+                relativeTo = DateTime.UtcNow;
+
+            DateTime start = relativeTo.Value.Subtract(range);
 
-            var entries = this._counter.Where(x => (x.EventTime >= start) && (x.EventTime <= lastTime));
-            return entries.Average(x => x.Elapsed.TotalMilliseconds);
+            var entries = this._counter.Where(x => (x.EventTime >= start) && (x.EventTime <= relativeTo));
+            return entries.Average(x => x.ElapsedMilliseconds);
         }
     }
 }
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs
index 343fddf6..b48efd67 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs
@@ -2,23 +2,41 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using StardewModdingAPI.Framework.Utilities;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
     internal class PerformanceCounterCollection
     {
-        public IDictionary<string, PerformanceCounter> PerformanceCounters { get; } = new Dictionary<string, PerformanceCounter>();
-        private DateTime StartDateTime = DateTime.Now;
-        private long CallCount;
-        public string Name { get; private set; }
-        public bool IsImportant { get; set; }
-        private readonly Stopwatch Stopwatch = new Stopwatch();
-        private readonly PerformanceCounterManager PerformanceCounterManager;
-        public double MonitorThresholdMilliseconds { get; set; }
-        public bool Monitor { get; set; }
+        /// <summary>The list of triggered performance counters.</summary>
         private readonly List<AlertContext> TriggeredPerformanceCounters = new List<AlertContext>();
 
+        /// <summary>The stopwatch used to track the invocation time.</summary>
+        private readonly Stopwatch InvocationStopwatch = new Stopwatch();
+
+        /// <summary>The performance counter manager.</summary>
+        private readonly PerformanceCounterManager PerformanceCounterManager;
+
+        /// <summary>Holds the time to calculate the average calls per second.</summary>
+        private DateTime CallsPerSecondStart = DateTime.UtcNow;
+
+        /// <summary>The number of invocations of this collection.</summary>
+        private long CallCount;
+
+        public IDictionary<string, PerformanceCounter> PerformanceCounters { get; } = new Dictionary<string, PerformanceCounter>();
+
+        /// <summary>The name of this collection.</summary>
+        public string Name { get; }
+
+        /// <summary>Flag if this collection is important (used for the console summary command).</summary>
+        public bool IsImportant { get; }
+
+        /// <summary>The alert threshold in milliseconds.</summary>
+        public double AlertThresholdMilliseconds { get; set; }
+
+        /// <summary>If alerting is enabled or not</summary>
+        public bool EnableAlerts { get; set; }
+
+
         public PerformanceCounterCollection(PerformanceCounterManager performanceCounterManager, string name, bool isImportant)
         {
             this.Name = name;
@@ -32,111 +50,120 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
             this.Name = name;
         }
 
+        /// <summary>Tracks a single invocation for a named source.</summary>
+        /// <param name="source">The name of the source.</param>
+        /// <param name="entry">The entry.</param>
         public void Track(string source, PerformanceCounterEntry entry)
         {
             if (!this.PerformanceCounters.ContainsKey(source))
-            {
                 this.PerformanceCounters.Add(source, new PerformanceCounter(this, source));
-            }
+
             this.PerformanceCounters[source].Add(entry);
 
-            if (this.Monitor)
-            {
-                this.TriggeredPerformanceCounters.Add(new AlertContext(source, entry.Elapsed.TotalMilliseconds));
-            }
+            if (this.EnableAlerts)
+                this.TriggeredPerformanceCounters.Add(new AlertContext(source, entry.ElapsedMilliseconds));
         }
 
+        /// <summary>Returns the average execution time for all non-game internal sources.</summary>
+        /// <returns>The average execution time in milliseconds</returns>
         public double GetModsAverageExecutionTime()
         {
-            return this.PerformanceCounters.Where(p => p.Key != Constants.GamePerformanceCounterName).Sum(p => p.Value.GetAverage());
+            return this.PerformanceCounters.Where(p =>
+                p.Key != Constants.GamePerformanceCounterName).Sum(p => p.Value.GetAverage());
         }
 
+        /// <summary>Returns the overall average execution time.</summary>
+        /// <returns>The average execution time in milliseconds</returns>
         public double GetAverageExecutionTime()
         {
             return this.PerformanceCounters.Sum(p => p.Value.GetAverage());
         }
 
+        /// <summary>Returns the average execution time for game-internal sources.</summary>
+        /// <returns>The average execution time in milliseconds</returns>
         public double GetGameAverageExecutionTime()
         {
             if (this.PerformanceCounters.TryGetValue(Constants.GamePerformanceCounterName, out PerformanceCounter gameExecTime))
-            {
                 return gameExecTime.GetAverage();
-            }
 
             return 0;
         }
 
+        /// <summary>Begins tracking the invocation of this collection.</summary>
         public void BeginTrackInvocation()
         {
-            if (this.Monitor)
+            if (this.EnableAlerts)
             {
                 this.TriggeredPerformanceCounters.Clear();
-                this.Stopwatch.Reset();
-                this.Stopwatch.Start();
+                this.InvocationStopwatch.Reset();
+                this.InvocationStopwatch.Start();
             }
 
             this.CallCount++;
-
         }
 
+        /// <summary>Ends tracking the invocation of this collection. Also records an alert if alerting is enabled
+        /// and the invocation time exceeds the threshold.</summary>
         public void EndTrackInvocation()
         {
-            if (!this.Monitor) return;
+            if (!this.EnableAlerts) return;
 
-            this.Stopwatch.Stop();
-            if (this.Stopwatch.Elapsed.TotalMilliseconds >= this.MonitorThresholdMilliseconds)
-            {
-                this.AddAlert(this.Stopwatch.Elapsed.TotalMilliseconds,
-                    this.MonitorThresholdMilliseconds, this.TriggeredPerformanceCounters);
-            }
+            this.InvocationStopwatch.Stop();
+
+            if (this.InvocationStopwatch.Elapsed.TotalMilliseconds >= this.AlertThresholdMilliseconds)
+                this.AddAlert(this.InvocationStopwatch.Elapsed.TotalMilliseconds,
+                    this.AlertThresholdMilliseconds, this.TriggeredPerformanceCounters);
         }
 
-        public void AddAlert(double executionTimeMilliseconds, double threshold, List<AlertContext> alerts)
+        /// <summary>Adds an alert.</summary>
+        /// <param name="executionTimeMilliseconds">The execution time in milliseconds.</param>
+        /// <param name="thresholdMilliseconds">The configured threshold.</param>
+        /// <param name="alerts">The list of alert contexts.</param>
+        public void AddAlert(double executionTimeMilliseconds, double thresholdMilliseconds, List<AlertContext> alerts)
         {
             this.PerformanceCounterManager.AddAlert(new AlertEntry(this, executionTimeMilliseconds,
-                threshold, alerts));
+                thresholdMilliseconds, alerts));
         }
 
-        public void AddAlert(double executionTimeMilliseconds, double threshold, AlertContext alert)
+        /// <summary>Adds an alert for a single AlertContext</summary>
+        /// <param name="executionTimeMilliseconds">The execution time in milliseconds.</param>
+        /// <param name="thresholdMilliseconds">The configured threshold.</param>
+        /// <param name="alert">The context</param>
+        public void AddAlert(double executionTimeMilliseconds, double thresholdMilliseconds, AlertContext alert)
         {
-            this.AddAlert(executionTimeMilliseconds, threshold, new List<AlertContext>() {alert});
+            this.AddAlert(executionTimeMilliseconds, thresholdMilliseconds, new List<AlertContext>() {alert});
         }
 
+        /// <summary>Resets the calls per second counter.</summary>
         public void ResetCallsPerSecond()
         {
             this.CallCount = 0;
-            this.StartDateTime = DateTime.Now;
+            this.CallsPerSecondStart = DateTime.UtcNow;
         }
 
+        /// <summary>Resets all performance counters in this collection.</summary>
         public void Reset()
         {
             foreach (var i in this.PerformanceCounters)
-            {
                 i.Value.Reset();
-                i.Value.ResetPeak();
-            }
         }
 
+        /// <summary>Resets the performance counter for a specific source.</summary>
+        /// <param name="source">The source name</param>
         public void ResetSource(string source)
         {
             foreach (var i in this.PerformanceCounters)
-            {
                 if (i.Value.Source.Equals(source, StringComparison.InvariantCultureIgnoreCase))
-                {
                     i.Value.Reset();
-                    i.Value.ResetPeak();
-                }
-            }
         }
 
+        /// <summary>Returns the average calls per second.</summary>
+        /// <returns>The average calls per second.</returns>
         public long GetAverageCallsPerSecond()
         {
-            long runtimeInSeconds = (long) DateTime.Now.Subtract(this.StartDateTime).TotalSeconds;
+            long runtimeInSeconds = (long) DateTime.UtcNow.Subtract(this.CallsPerSecondStart).TotalSeconds;
 
-            if (runtimeInSeconds == 0)
-            {
-                return 0;
-            }
+            if (runtimeInSeconds == 0) return 0;
 
             return this.CallCount / runtimeInSeconds;
         }
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs
index 8e156a32..a50fce7d 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs
@@ -1,10 +1,14 @@
 using System;
 
-namespace StardewModdingAPI.Framework.Utilities
+namespace StardewModdingAPI.Framework.PerformanceCounter
 {
-    public struct PerformanceCounterEntry
+    /// <summary>A single performance counter entry. Records the DateTime of the event and the elapsed millisecond.</summary>
+    internal struct PerformanceCounterEntry
     {
+        /// <summary>The DateTime when the entry occured.</summary>
         public DateTime EventTime;
-        public TimeSpan Elapsed;
+
+        /// <summary>The elapsed milliseconds</summary>
+        public double ElapsedMilliseconds;
     }
 }
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs
index 9e77e2fa..d8f1f172 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs
@@ -4,72 +4,62 @@ using System.Diagnostics;
 using System.Linq;
 using System.Text;
 using StardewModdingAPI.Framework.Events;
-using StardewModdingAPI.Framework.Utilities;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
     internal class PerformanceCounterManager
     {
         public HashSet<PerformanceCounterCollection> PerformanceCounterCollections = new HashSet<PerformanceCounterCollection>();
-        public List<AlertEntry> Alerts = new List<AlertEntry>();
+
+        /// <summary>The recorded alerts.</summary>
+        private readonly List<AlertEntry> Alerts = new List<AlertEntry>();
+
+        /// <summary>The monitor for output logging.</summary>
         private readonly IMonitor Monitor;
-        private readonly Stopwatch Stopwatch = new Stopwatch();
 
+        /// <summary>The invocation stopwatch.</summary>
+        private readonly Stopwatch InvocationStopwatch = new Stopwatch();
+
+        /// <summary>Constructs a performance counter manager.</summary>
+        /// <param name="monitor">The monitor for output logging.</param>
         public PerformanceCounterManager(IMonitor monitor)
         {
             this.Monitor = monitor;
         }
 
+        /// <summary>Resets all performance counters in all collections.</summary>
         public void Reset()
         {
-            foreach (var performanceCounter in this.PerformanceCounterCollections)
-            {
-                foreach (var eventPerformanceCounter in performanceCounter.PerformanceCounters)
-                {
-                    eventPerformanceCounter.Value.Reset();
-                }
-            }
-        }
-
-        /// <summary>Print any queued messages.</summary>
-        public void PrintQueued()
-        {
-            if (this.Alerts.Count == 0)
+            foreach (var eventPerformanceCounter in
+                this.PerformanceCounterCollections.SelectMany(performanceCounter => performanceCounter.PerformanceCounters))
             {
-                return;
+                eventPerformanceCounter.Value.Reset();
             }
-            StringBuilder sb = new StringBuilder();
-
-            foreach (var alert in this.Alerts)
-            {
-                sb.AppendLine($"{alert.Collection.Name} took {alert.ExecutionTimeMilliseconds:F2}ms (exceeded threshold of {alert.Threshold:F2}ms)");
-
-                foreach (var context in alert.Context)
-                {
-                    sb.AppendLine($"{context.Source}: {context.Elapsed:F2}ms");
-                }
-            }
-
-            this.Alerts.Clear();
-
-            this.Monitor.Log(sb.ToString(), LogLevel.Error);
         }
 
+        /// <summary>Begins tracking the invocation for a collection.</summary>
+        /// <param name="collectionName">The collection name</param>
         public void BeginTrackInvocation(string collectionName)
         {
             this.GetOrCreateCollectionByName(collectionName).BeginTrackInvocation();
         }
 
+        /// <summary>Ends tracking the invocation for a collection.</summary>
+        /// <param name="collectionName"></param>
         public void EndTrackInvocation(string collectionName)
         {
             this.GetOrCreateCollectionByName(collectionName).EndTrackInvocation();
         }
 
-        public void Track(string collectionName, string modName, Action action)
+        /// <summary>Tracks a single performance counter invocation in a specific collection.</summary>
+        /// <param name="collectionName">The name of the collection.</param>
+        /// <param name="sourceName">The name of the source.</param>
+        /// <param name="action">The action to execute and track invocation time for.</param>
+        public void Track(string collectionName, string sourceName, Action action)
         {
             DateTime eventTime = DateTime.UtcNow;
-            this.Stopwatch.Reset();
-            this.Stopwatch.Start();
+            this.InvocationStopwatch.Reset();
+            this.InvocationStopwatch.Start();
 
             try
             {
@@ -77,75 +67,102 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
             }
             finally
             {
-                this.Stopwatch.Stop();
+                this.InvocationStopwatch.Stop();
 
-                this.GetOrCreateCollectionByName(collectionName).Track(modName, new PerformanceCounterEntry
+                this.GetOrCreateCollectionByName(collectionName).Track(sourceName, new PerformanceCounterEntry
                 {
                     EventTime = eventTime,
-                    Elapsed = this.Stopwatch.Elapsed
+                    ElapsedMilliseconds = this.InvocationStopwatch.Elapsed.TotalMilliseconds
                 });
             }
         }
 
-        public PerformanceCounterCollection GetCollectionByName(string name)
+        /// <summary>Gets a collection by name.</summary>
+        /// <param name="name">The name of the collection.</param>
+        /// <returns>The collection or null if none was found.</returns>
+        private PerformanceCounterCollection GetCollectionByName(string name)
         {
             return this.PerformanceCounterCollections.FirstOrDefault(collection => collection.Name == name);
         }
 
-        public PerformanceCounterCollection GetOrCreateCollectionByName(string name)
+        /// <summary>Gets a collection by name and creates it if it doesn't exist.</summary>
+        /// <param name="name">The name of the collection.</param>
+        /// <returns>The collection.</returns>
+        private PerformanceCounterCollection GetOrCreateCollectionByName(string name)
         {
             PerformanceCounterCollection collection = this.GetCollectionByName(name);
 
-            if (collection == null)
-            {
-                collection = new PerformanceCounterCollection(this, name);
-                this.PerformanceCounterCollections.Add(collection);
-            }
+            if (collection != null) return collection;
+
+            collection = new PerformanceCounterCollection(this, name);
+            this.PerformanceCounterCollections.Add(collection);
 
             return collection;
         }
 
-        public void ResetCategory(string name)
+        /// <summary>Resets the performance counters for a specific collection.</summary>
+        /// <param name="name">The collection name.</param>
+        public void ResetCollection(string name)
         {
-            foreach (var performanceCounterCollection in this.PerformanceCounterCollections)
+            foreach (PerformanceCounterCollection performanceCounterCollection in
+                this.PerformanceCounterCollections.Where(performanceCounterCollection =>
+                    performanceCounterCollection.Name.Equals(name, StringComparison.InvariantCultureIgnoreCase)))
             {
-                if (performanceCounterCollection.Name.Equals(name, StringComparison.InvariantCultureIgnoreCase))
-                {
-                    performanceCounterCollection.ResetCallsPerSecond();
-                    performanceCounterCollection.Reset();
-                }
+                performanceCounterCollection.ResetCallsPerSecond();
+                performanceCounterCollection.Reset();
             }
         }
 
+        /// <summary>Resets performance counters for a specific source.</summary>
+        /// <param name="name">The name of the source.</param>
         public void ResetSource(string name)
         {
-            foreach (var performanceCounterCollection in this.PerformanceCounterCollections)
-            {
+            foreach (PerformanceCounterCollection performanceCounterCollection in this.PerformanceCounterCollections)
                 performanceCounterCollection.ResetSource(name);
-            }
         }
 
+        /// <summary>Print any queued alerts.</summary>
+        public void PrintQueuedAlerts()
+        {
+            if (this.Alerts.Count == 0) return;
+
+            StringBuilder sb = new StringBuilder();
+
+            foreach (AlertEntry alert in this.Alerts)
+            {
+                sb.AppendLine($"{alert.Collection.Name} took {alert.ExecutionTimeMilliseconds:F2}ms (exceeded threshold of {alert.ThresholdMilliseconds:F2}ms)");
 
+                foreach (AlertContext context in alert.Context.OrderByDescending(p => p.Elapsed))
+                    sb.AppendLine(context.ToString());
+            }
+
+            this.Alerts.Clear();
+            this.Monitor.Log(sb.ToString(), LogLevel.Error);
+        }
+
+        /// <summary>Adds an alert to the queue.</summary>
+        /// <param name="entry">The alert to add.</param>
         public void AddAlert(AlertEntry entry)
         {
             this.Alerts.Add(entry);
         }
 
-        public void InitializePerformanceCounterEvents(EventManager eventManager)
+        /// <summary>Initialized the default performance counter collections.</summary>
+        /// <param name="eventManager">The event manager.</param>
+        public void InitializePerformanceCounterCollections(EventManager eventManager)
         {
             this.PerformanceCounterCollections = new HashSet<PerformanceCounterCollection>()
             {
                 new EventPerformanceCounterCollection(this, eventManager.MenuChanged, false),
 
-
                 // Rendering Events
-                new EventPerformanceCounterCollection(this, eventManager.Rendering, true),
+                new EventPerformanceCounterCollection(this, eventManager.Rendering, false),
                 new EventPerformanceCounterCollection(this, eventManager.Rendered, true),
-                new EventPerformanceCounterCollection(this, eventManager.RenderingWorld, true),
+                new EventPerformanceCounterCollection(this, eventManager.RenderingWorld, false),
                 new EventPerformanceCounterCollection(this, eventManager.RenderedWorld, true),
-                new EventPerformanceCounterCollection(this, eventManager.RenderingActiveMenu, true),
+                new EventPerformanceCounterCollection(this, eventManager.RenderingActiveMenu, false),
                 new EventPerformanceCounterCollection(this, eventManager.RenderedActiveMenu, true),
-                new EventPerformanceCounterCollection(this, eventManager.RenderingHud, true),
+                new EventPerformanceCounterCollection(this, eventManager.RenderingHud, false),
                 new EventPerformanceCounterCollection(this, eventManager.RenderedHud, true),
 
                 new EventPerformanceCounterCollection(this, eventManager.WindowResized, false),
@@ -172,19 +189,19 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
                 new EventPerformanceCounterCollection(this, eventManager.CursorMoved, true),
                 new EventPerformanceCounterCollection(this, eventManager.MouseWheelScrolled, true),
 
-                new EventPerformanceCounterCollection(this, eventManager.PeerContextReceived, true),
-                new EventPerformanceCounterCollection(this, eventManager.ModMessageReceived, true),
-                new EventPerformanceCounterCollection(this, eventManager.PeerDisconnected, true),
+                new EventPerformanceCounterCollection(this, eventManager.PeerContextReceived, false),
+                new EventPerformanceCounterCollection(this, eventManager.ModMessageReceived, false),
+                new EventPerformanceCounterCollection(this, eventManager.PeerDisconnected, false),
                 new EventPerformanceCounterCollection(this, eventManager.InventoryChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.LevelChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.Warped, true),
+                new EventPerformanceCounterCollection(this, eventManager.LevelChanged, false),
+                new EventPerformanceCounterCollection(this, eventManager.Warped, false),
 
-                new EventPerformanceCounterCollection(this, eventManager.LocationListChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.BuildingListChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.LocationListChanged, true),
+                new EventPerformanceCounterCollection(this, eventManager.LocationListChanged, false),
+                new EventPerformanceCounterCollection(this, eventManager.BuildingListChanged, false),
+                new EventPerformanceCounterCollection(this, eventManager.LocationListChanged, false),
                 new EventPerformanceCounterCollection(this, eventManager.DebrisListChanged, true),
                 new EventPerformanceCounterCollection(this, eventManager.LargeTerrainFeatureListChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.NpcListChanged, true),
+                new EventPerformanceCounterCollection(this, eventManager.NpcListChanged, false),
                 new EventPerformanceCounterCollection(this, eventManager.ObjectListChanged, true),
                 new EventPerformanceCounterCollection(this, eventManager.ChestInventoryChanged, true),
                 new EventPerformanceCounterCollection(this, eventManager.TerrainFeatureListChanged, true),
diff --git a/src/SMAPI/Framework/SCore.cs b/src/SMAPI/Framework/SCore.cs
index 5b0c6691..af7513e3 100644
--- a/src/SMAPI/Framework/SCore.cs
+++ b/src/SMAPI/Framework/SCore.cs
@@ -169,7 +169,7 @@ namespace StardewModdingAPI.Framework
 
             SCore.PerformanceCounterManager = new PerformanceCounterManager(this.Monitor);
             this.EventManager = new EventManager(this.Monitor, this.ModRegistry, SCore.PerformanceCounterManager);
-            SCore.PerformanceCounterManager.InitializePerformanceCounterEvents(this.EventManager);
+            SCore.PerformanceCounterManager.InitializePerformanceCounterCollections(this.EventManager);
 
             SCore.DeprecationManager = new DeprecationManager(this.Monitor, this.ModRegistry);
 
diff --git a/src/SMAPI/Framework/SGame.cs b/src/SMAPI/Framework/SGame.cs
index 8aba9b57..266e2e6f 100644
--- a/src/SMAPI/Framework/SGame.cs
+++ b/src/SMAPI/Framework/SGame.cs
@@ -312,7 +312,7 @@ namespace StardewModdingAPI.Framework
             try
             {
                 this.DeprecationManager.PrintQueued();
-                this.PerformanceCounterManager.PrintQueued();
+                this.PerformanceCounterManager.PrintQueuedAlerts();
 
                 /*********
                 ** First-tick initialization