refactor performance counter code

This commit performs some general refactoring, including...
- avoid manually duplicating the event list;
- rework the 'is important' event flag;
- remove the new packages (Cyotek.Collections can be replaced with built-in types, and System.ValueTuple won't work in the Mono version used on Linux/Mac);
- improve performance;
- minor cleanup.

13 files changed, 380 insertions, 438 deletions

diff --git a/src/SMAPI/Framework/Events/EventManager.cs b/src/SMAPI/Framework/Events/EventManager.cs
index 19a4dff8..50dcc9ef 100644
--- a/src/SMAPI/Framework/Events/EventManager.cs
+++ b/src/SMAPI/Framework/Events/EventManager.cs
@@ -1,4 +1,6 @@
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
 using StardewModdingAPI.Events;
 using StardewModdingAPI.Framework.PerformanceCounter;
 
@@ -174,29 +176,32 @@ namespace StardewModdingAPI.Framework.Events
         /// <summary>Construct an instance.</summary>
         /// <param name="monitor">Writes messages to the log.</param>
         /// <param name="modRegistry">The mod registry with which to identify mods.</param>
-        /// <param name="performanceCounterManager">The performance counter manager.</param>
-        public EventManager(IMonitor monitor, ModRegistry modRegistry, PerformanceCounterManager performanceCounterManager)
+        /// <param name="performanceMonitor">Tracks performance metrics.</param>
+        public EventManager(IMonitor monitor, ModRegistry modRegistry, PerformanceMonitor performanceMonitor)
         {
             // create shortcut initializers
-            ManagedEvent<TEventArgs> ManageEventOf<TEventArgs>(string typeName, string eventName) => new ManagedEvent<TEventArgs>($"{typeName}.{eventName}", monitor, modRegistry, performanceCounterManager);
+            ManagedEvent<TEventArgs> ManageEventOf<TEventArgs>(string typeName, string eventName, bool isPerformanceCritical = false)
+            {
+                return new ManagedEvent<TEventArgs>($"{typeName}.{eventName}", monitor, modRegistry, performanceMonitor, isPerformanceCritical);
+            }
 
             // init events (new)
             this.MenuChanged = ManageEventOf<MenuChangedEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.MenuChanged));
-            this.Rendering = ManageEventOf<RenderingEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.Rendering));
-            this.Rendered = ManageEventOf<RenderedEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.Rendered));
-            this.RenderingWorld = ManageEventOf<RenderingWorldEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderingWorld));
-            this.RenderedWorld = ManageEventOf<RenderedWorldEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderedWorld));
-            this.RenderingActiveMenu = ManageEventOf<RenderingActiveMenuEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderingActiveMenu));
-            this.RenderedActiveMenu = ManageEventOf<RenderedActiveMenuEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderedActiveMenu));
-            this.RenderingHud = ManageEventOf<RenderingHudEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderingHud));
-            this.RenderedHud = ManageEventOf<RenderedHudEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderedHud));
+            this.Rendering = ManageEventOf<RenderingEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.Rendering), isPerformanceCritical: true);
+            this.Rendered = ManageEventOf<RenderedEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.Rendered), isPerformanceCritical: true);
+            this.RenderingWorld = ManageEventOf<RenderingWorldEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderingWorld), isPerformanceCritical: true);
+            this.RenderedWorld = ManageEventOf<RenderedWorldEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderedWorld), isPerformanceCritical: true);
+            this.RenderingActiveMenu = ManageEventOf<RenderingActiveMenuEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderingActiveMenu), isPerformanceCritical: true);
+            this.RenderedActiveMenu = ManageEventOf<RenderedActiveMenuEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderedActiveMenu), isPerformanceCritical: true);
+            this.RenderingHud = ManageEventOf<RenderingHudEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderingHud), isPerformanceCritical: true);
+            this.RenderedHud = ManageEventOf<RenderedHudEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.RenderedHud), isPerformanceCritical: true);
             this.WindowResized = ManageEventOf<WindowResizedEventArgs>(nameof(IModEvents.Display), nameof(IDisplayEvents.WindowResized));
 
             this.GameLaunched = ManageEventOf<GameLaunchedEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.GameLaunched));
-            this.UpdateTicking = ManageEventOf<UpdateTickingEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.UpdateTicking));
-            this.UpdateTicked = ManageEventOf<UpdateTickedEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.UpdateTicked));
-            this.OneSecondUpdateTicking = ManageEventOf<OneSecondUpdateTickingEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.OneSecondUpdateTicking));
-            this.OneSecondUpdateTicked = ManageEventOf<OneSecondUpdateTickedEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.OneSecondUpdateTicked));
+            this.UpdateTicking = ManageEventOf<UpdateTickingEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.UpdateTicking), isPerformanceCritical: true);
+            this.UpdateTicked = ManageEventOf<UpdateTickedEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.UpdateTicked), isPerformanceCritical: true);
+            this.OneSecondUpdateTicking = ManageEventOf<OneSecondUpdateTickingEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.OneSecondUpdateTicking), isPerformanceCritical: true);
+            this.OneSecondUpdateTicked = ManageEventOf<OneSecondUpdateTickedEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.OneSecondUpdateTicked), isPerformanceCritical: true);
             this.SaveCreating = ManageEventOf<SaveCreatingEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.SaveCreating));
             this.SaveCreated = ManageEventOf<SaveCreatedEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.SaveCreated));
             this.Saving = ManageEventOf<SavingEventArgs>(nameof(IModEvents.GameLoop), nameof(IGameLoopEvents.Saving));
@@ -209,7 +214,7 @@ namespace StardewModdingAPI.Framework.Events
 
             this.ButtonPressed = ManageEventOf<ButtonPressedEventArgs>(nameof(IModEvents.Input), nameof(IInputEvents.ButtonPressed));
             this.ButtonReleased = ManageEventOf<ButtonReleasedEventArgs>(nameof(IModEvents.Input), nameof(IInputEvents.ButtonReleased));
-            this.CursorMoved = ManageEventOf<CursorMovedEventArgs>(nameof(IModEvents.Input), nameof(IInputEvents.CursorMoved));
+            this.CursorMoved = ManageEventOf<CursorMovedEventArgs>(nameof(IModEvents.Input), nameof(IInputEvents.CursorMoved), isPerformanceCritical: true);
             this.MouseWheelScrolled = ManageEventOf<MouseWheelScrolledEventArgs>(nameof(IModEvents.Input), nameof(IInputEvents.MouseWheelScrolled));
 
             this.PeerContextReceived = ManageEventOf<PeerContextReceivedEventArgs>(nameof(IModEvents.Multiplayer), nameof(IMultiplayerEvents.PeerContextReceived));
@@ -230,8 +235,15 @@ namespace StardewModdingAPI.Framework.Events
             this.TerrainFeatureListChanged = ManageEventOf<TerrainFeatureListChangedEventArgs>(nameof(IModEvents.World), nameof(IWorldEvents.TerrainFeatureListChanged));
 
             this.LoadStageChanged = ManageEventOf<LoadStageChangedEventArgs>(nameof(IModEvents.Specialized), nameof(ISpecializedEvents.LoadStageChanged));
-            this.UnvalidatedUpdateTicking = ManageEventOf<UnvalidatedUpdateTickingEventArgs>(nameof(IModEvents.Specialized), nameof(ISpecializedEvents.UnvalidatedUpdateTicking));
-            this.UnvalidatedUpdateTicked = ManageEventOf<UnvalidatedUpdateTickedEventArgs>(nameof(IModEvents.Specialized), nameof(ISpecializedEvents.UnvalidatedUpdateTicked));
+            this.UnvalidatedUpdateTicking = ManageEventOf<UnvalidatedUpdateTickingEventArgs>(nameof(IModEvents.Specialized), nameof(ISpecializedEvents.UnvalidatedUpdateTicking), isPerformanceCritical: true);
+            this.UnvalidatedUpdateTicked = ManageEventOf<UnvalidatedUpdateTickedEventArgs>(nameof(IModEvents.Specialized), nameof(ISpecializedEvents.UnvalidatedUpdateTicked), isPerformanceCritical: true);
+        }
+
+        /// <summary>Get all managed events.</summary>
+        public IEnumerable<IManagedEvent> GetAllEvents()
+        {
+            foreach (FieldInfo field in this.GetType().GetFields())
+                yield return (IManagedEvent)field.GetValue(this);
         }
     }
 }
diff --git a/src/SMAPI/Framework/Events/IManagedEvent.cs b/src/SMAPI/Framework/Events/IManagedEvent.cs
index 04476866..e4e3ca08 100644
--- a/src/SMAPI/Framework/Events/IManagedEvent.cs
+++ b/src/SMAPI/Framework/Events/IManagedEvent.cs
@@ -1,7 +1,15 @@
 namespace StardewModdingAPI.Framework.Events
 {
+    /// <summary>Metadata for an event raised by SMAPI.</summary>
     internal interface IManagedEvent
     {
-        string GetName();
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>A human-readable name for the event.</summary>
+        string EventName { get; }
+
+        /// <summary>Whether the event is typically called at least once per second.</summary>
+        bool IsPerformanceCritical { get; }
     }
 }
diff --git a/src/SMAPI/Framework/Events/ManagedEvent.cs b/src/SMAPI/Framework/Events/ManagedEvent.cs
index dfdd7449..60e5c599 100644
--- a/src/SMAPI/Framework/Events/ManagedEvent.cs
+++ b/src/SMAPI/Framework/Events/ManagedEvent.cs
@@ -1,13 +1,13 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using PerformanceCounterManager = StardewModdingAPI.Framework.PerformanceCounter.PerformanceCounterManager;
+using StardewModdingAPI.Framework.PerformanceCounter;
 
 namespace StardewModdingAPI.Framework.Events
 {
     /// <summary>An event wrapper which intercepts and logs errors in handler code.</summary>
     /// <typeparam name="TEventArgs">The event arguments type.</typeparam>
-    internal class ManagedEvent<TEventArgs>: IManagedEvent
+    internal class ManagedEvent<TEventArgs> : IManagedEvent
     {
         /*********
         ** Fields
@@ -15,9 +15,6 @@ namespace StardewModdingAPI.Framework.Events
         /// <summary>The underlying event.</summary>
         private event EventHandler<TEventArgs> Event;
 
-        /// <summary>A human-readable name for the event.</summary>
-        private readonly string EventName;
-
         /// <summary>Writes messages to the log.</summary>
         private readonly IMonitor Monitor;
 
@@ -30,8 +27,19 @@ namespace StardewModdingAPI.Framework.Events
         /// <summary>The cached invocation list.</summary>
         private EventHandler<TEventArgs>[] CachedInvocationList;
 
-        /// <summary>The performance counter manager.</summary>
-        private readonly PerformanceCounterManager PerformanceCounterManager;
+        /// <summary>Tracks performance metrics.</summary>
+        private readonly PerformanceMonitor PerformanceMonitor;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>A human-readable name for the event.</summary>
+        public string EventName { get; }
+
+        /// <summary>Whether the event is typically called at least once per second.</summary>
+        public bool IsPerformanceCritical { get; }
+
 
         /*********
         ** Public methods
@@ -40,19 +48,15 @@ namespace StardewModdingAPI.Framework.Events
         /// <param name="eventName">A human-readable name for the event.</param>
         /// <param name="monitor">Writes messages to the log.</param>
         /// <param name="modRegistry">The mod registry with which to identify mods.</param>
-        /// <param name="performanceCounterManager">The performance counter manager</param>
-        public ManagedEvent(string eventName, IMonitor monitor, ModRegistry modRegistry, PerformanceCounterManager performanceCounterManager)
+        /// <param name="performanceMonitor">Tracks performance metrics.</param>
+        /// <param name="isPerformanceCritical">Whether the event is typically called at least once per second.</param>
+        public ManagedEvent(string eventName, IMonitor monitor, ModRegistry modRegistry, PerformanceMonitor performanceMonitor, bool isPerformanceCritical = false)
         {
             this.EventName = eventName;
             this.Monitor = monitor;
             this.ModRegistry = modRegistry;
-            this.PerformanceCounterManager = performanceCounterManager;
-        }
-
-        /// <summary>Gets the event name.</summary>
-        public string GetName()
-        {
-            return this.EventName;
+            this.PerformanceMonitor = performanceMonitor;
+            this.IsPerformanceCritical = isPerformanceCritical;
         }
 
         /// <summary>Get whether anything is listening to the event.</summary>
@@ -93,22 +97,20 @@ namespace StardewModdingAPI.Framework.Events
                 return;
 
 
-            this.PerformanceCounterManager.BeginTrackInvocation(this.EventName);
-
-            foreach (EventHandler<TEventArgs> handler in this.CachedInvocationList)
+            this.PerformanceMonitor.Track(this.EventName, () =>
             {
-                try
-                {
-                    this.PerformanceCounterManager.Track(this.EventName, this.GetModNameForPerformanceCounters(handler),
-                        () => handler.Invoke(null, args));
-                }
-                catch (Exception ex)
+                foreach (EventHandler<TEventArgs> handler in this.CachedInvocationList)
                 {
-                    this.LogError(handler, ex);
+                    try
+                    {
+                        this.PerformanceMonitor.Track(this.EventName, this.GetModNameForPerformanceCounters(handler), () => handler.Invoke(null, args));
+                    }
+                    catch (Exception ex)
+                    {
+                        this.LogError(handler, ex);
+                    }
                 }
-            }
-
-            this.PerformanceCounterManager.EndTrackInvocation(this.EventName);
+            });
         }
 
         /// <summary>Raise the event and notify all handlers.</summary>
@@ -139,18 +141,17 @@ namespace StardewModdingAPI.Framework.Events
         /*********
         ** Private methods
         *********/
-
+        /// <summary>Get the mod name for a given event handler to display in performance monitoring reports.</summary>
+        /// <param name="handler">The event handler.</param>
         private string GetModNameForPerformanceCounters(EventHandler<TEventArgs> handler)
         {
             IModMetadata mod = this.GetSourceMod(handler);
-
             if (mod == null)
-            {
                 return Constants.GamePerformanceCounterName;
-            }
-
-            return mod.HasManifest() ? mod.Manifest.UniqueID : mod.DisplayName;
 
+            return mod.HasManifest()
+                ? mod.Manifest.UniqueID
+                : mod.DisplayName;
         }
 
         /// <summary>Track an event handler.</summary>
diff --git a/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs b/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs
index 63f0a5ed..76c472e1 100644
--- a/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/AlertContext.cs
@@ -3,13 +3,20 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
     /// <summary>The context for an alert.</summary>
     internal struct AlertContext
     {
+        /*********
+        ** Accessors
+        *********/
         /// <summary>The source which triggered the alert.</summary>
-        public readonly string Source;
+        public string Source { get; }
 
         /// <summary>The elapsed milliseconds.</summary>
-        public readonly double Elapsed;
+        public double Elapsed { get; }
 
-        /// <summary>Creates a new alert context.</summary>
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
         /// <param name="source">The source which triggered the alert.</param>
         /// <param name="elapsed">The elapsed milliseconds.</param>
         public AlertContext(string source, double elapsed)
@@ -18,6 +25,7 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
             this.Elapsed = elapsed;
         }
 
+        /// <summary>Get a human-readable text form of this instance.</summary>
         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 b87d8642..494f34a9 100644
--- a/src/SMAPI/Framework/PerformanceCounter/AlertEntry.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/AlertEntry.cs
@@ -1,28 +1,33 @@
-using System.Collections.Generic;
-
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
     /// <summary>A single alert entry.</summary>
     internal struct AlertEntry
     {
+        /*********
+        ** Accessors
+        *********/
         /// <summary>The collection in which the alert occurred.</summary>
-        public readonly PerformanceCounterCollection Collection;
+        public PerformanceCounterCollection Collection { get; }
 
         /// <summary>The actual execution time in milliseconds.</summary>
-        public readonly double ExecutionTimeMilliseconds;
+        public double ExecutionTimeMilliseconds { get; }
+
+        /// <summary>The configured alert threshold in milliseconds.</summary>
+        public double ThresholdMilliseconds { get; }
 
-        /// <summary>The configured alert threshold. </summary>
-        public readonly double ThresholdMilliseconds;
+        /// <summary>The sources involved in exceeding the threshold.</summary>
+        public AlertContext[] Context { get; }
 
-        /// <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>
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="collection">The 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)
+        /// <param name="thresholdMilliseconds">The configured alert threshold in milliseconds.</param>
+        /// <param name="context">The sources involved in exceeding the threshold.</param>
+        public AlertEntry(PerformanceCounterCollection collection, double executionTimeMilliseconds, double thresholdMilliseconds, AlertContext[] context)
         {
             this.Collection = collection;
             this.ExecutionTimeMilliseconds = executionTimeMilliseconds;
diff --git a/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs b/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs
deleted file mode 100644
index 4690c512..00000000
--- a/src/SMAPI/Framework/PerformanceCounter/EventPerformanceCounterCollection.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-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/PeakEntry.cs b/src/SMAPI/Framework/PerformanceCounter/PeakEntry.cs
index 95dc11f4..abb29541 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PeakEntry.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PeakEntry.cs
@@ -1,20 +1,31 @@
 using System;
-using System.Collections.Generic;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
+    /// <summary>A peak invocation time.</summary>
     internal struct PeakEntry
     {
+        /*********
+        ** Accessors
+        *********/
         /// <summary>The actual execution time in milliseconds.</summary>
-        public readonly double ExecutionTimeMilliseconds;
+        public double ExecutionTimeMilliseconds { get; }
 
-        /// <summary>The DateTime when the entry occured.</summary>
-        public DateTime EventTime;
+        /// <summary>When the entry occurred.</summary>
+        public DateTime EventTime { get; }
 
-        /// <summary>The context list, which records all sources involved in exceeding the threshold.</summary>
-        public readonly List<AlertContext> Context;
+        /// <summary>The sources involved in exceeding the threshold.</summary>
+        public AlertContext[] Context { get; }
 
-        public PeakEntry(double executionTimeMilliseconds, DateTime eventTime, List<AlertContext> context)
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="executionTimeMilliseconds">The actual execution time in milliseconds.</param>
+        /// <param name="eventTime">When the entry occurred.</param>
+        /// <param name="context">The sources involved in exceeding the threshold.</param>
+        public PeakEntry(double executionTimeMilliseconds, DateTime eventTime, AlertContext[] context)
         {
             this.ExecutionTimeMilliseconds = executionTimeMilliseconds;
             this.EventTime = eventTime;
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs
index e9dfcb14..0fb6482d 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounter.cs
@@ -1,23 +1,32 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
-using Cyotek.Collections.Generic;
+using Harmony;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
+    /// <summary>Tracks metadata about a particular code event.</summary>
     internal class PerformanceCounter
     {
+        /*********
+        ** Fields
+        *********/
         /// <summary>The size of the ring buffer.</summary>
-        private const int MAX_ENTRIES = 16384;
+        private readonly int MaxEntries = 16384;
 
         /// <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 performance counter entries.</summary>
+        private readonly Stack<PerformanceCounterEntry> Entries;
 
-        /// <summary>The peak execution time</summary>
+        /// <summary>The entry with the highest execution time.</summary>
         private PerformanceCounterEntry? PeakPerformanceCounterEntry;
 
+
+        /*********
+        ** Accessors
+        *********/
         /// <summary>The name of the source.</summary>
         public string Source { get; }
 
@@ -27,118 +36,90 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
         /// <summary>If alerting is enabled or not</summary>
         public bool EnableAlerts { get; set; }
 
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="parentCollection">The collection to which this performance counter belongs.</param>
+        /// <param name="source">The name of the source.</param>
         public PerformanceCounter(PerformanceCounterCollection parentCollection, string source)
         {
             this.ParentCollection = parentCollection;
             this.Source = source;
-            this._counter = new CircularBuffer<PerformanceCounterEntry>(PerformanceCounter.MAX_ENTRIES);
+            this.Entries = new Stack<PerformanceCounterEntry>(this.MaxEntries);
         }
 
-        /// <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>
+        /// <summary>Add a performance counter entry to the list, update monitoring, and raise alerts if needed.</summary>
         /// <param name="entry">The entry to add.</param>
         public void Add(PerformanceCounterEntry entry)
         {
-            this._counter.Put(entry);
-
-            if (this.EnableAlerts && entry.ElapsedMilliseconds > this.AlertThresholdMilliseconds)
-                this.ParentCollection.AddAlert(entry.ElapsedMilliseconds, this.AlertThresholdMilliseconds,
-                    new AlertContext(this.Source, entry.ElapsedMilliseconds));
+            // add entry
+            if (this.Entries.Count > this.MaxEntries)
+                this.Entries.Pop();
+            this.Entries.Add(entry);
 
-            if (this.PeakPerformanceCounterEntry == null)
+            // update metrics
+            if (this.PeakPerformanceCounterEntry == null || entry.ElapsedMilliseconds > this.PeakPerformanceCounterEntry.Value.ElapsedMilliseconds)
                 this.PeakPerformanceCounterEntry = entry;
-            else
-            {
-                if (entry.ElapsedMilliseconds > this.PeakPerformanceCounterEntry.Value.ElapsedMilliseconds)
-                    this.PeakPerformanceCounterEntry = entry;
-            }
+
+            // raise alert
+            if (this.EnableAlerts && entry.ElapsedMilliseconds > this.AlertThresholdMilliseconds)
+                this.ParentCollection.AddAlert(entry.ElapsedMilliseconds, this.AlertThresholdMilliseconds, new AlertContext(this.Source, entry.ElapsedMilliseconds));
         }
 
-        /// <summary>Clears all performance counter entries and resets the peak entry.</summary>
+        /// <summary>Clear all performance counter entries and monitoring.</summary>
         public void Reset()
         {
-            this._counter.Clear();
+            this.Entries.Clear();
             this.PeakPerformanceCounterEntry = null;
         }
 
-        /// <summary>Returns the peak entry.</summary>
-        /// <returns>The peak entry.</returns>
+        /// <summary>Get the peak entry.</summary>
         public PerformanceCounterEntry? GetPeak()
         {
             return this.PeakPerformanceCounterEntry;
         }
 
-        /// <summary>Returns the peak entry.</summary>
-        /// <returns>The peak entry.</returns>
-        public PerformanceCounterEntry? GetPeak(TimeSpan range, DateTime? relativeTo = null)
+        /// <summary>Get the entry with the highest execution time.</summary>
+        /// <param name="range">The time range to search.</param>
+        /// <param name="endTime">The end time for the <paramref name="range"/>, or null for the current time.</param>
+        public PerformanceCounterEntry? GetPeak(TimeSpan range, DateTime? endTime = null)
         {
-            if (this._counter.IsEmpty)
-                return null;
-
-            if (relativeTo == null)
-                relativeTo = DateTime.UtcNow;
-
-            DateTime start = relativeTo.Value.Subtract(range);
-
-            var entries = this._counter.Where(x => (x.EventTime >= start) && (x.EventTime <= relativeTo)).ToList();
-
-            if (!entries.Any())
-                return null;
+            endTime ??= DateTime.UtcNow;
+            DateTime startTime = endTime.Value.Subtract(range);
 
-            return entries.OrderByDescending(x => x.ElapsedMilliseconds).First();
+            return this.Entries
+                .Where(entry => entry.EventTime >= startTime && entry.EventTime <= endTime)
+                .OrderByDescending(x => x.ElapsedMilliseconds)
+                .FirstOrDefault();
         }
 
-        /// <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>
+        /// <summary>Get the last entry added to the list.</summary>
         public PerformanceCounterEntry? GetLastEntry()
         {
-            if (this._counter.IsEmpty)
+            if (this.Entries.Count == 0)
                 return null;
 
-            return this._counter.PeekLast();
+            return this.Entries.Peek();
         }
 
-        /// <summary>Returns the average execution time of all entries.</summary>
-        /// <returns>The average execution time in milliseconds.</returns>
-        public double GetAverage()
+        /// <summary>Get the average over a given time span.</summary>
+        /// <param name="range">The time range to search.</param>
+        /// <param name="endTime">The end time for the <paramref name="range"/>, or null for the current time.</param>
+        public double GetAverage(TimeSpan range, DateTime? endTime = null)
         {
-            if (this._counter.IsEmpty)
-                return 0;
-
-            return this._counter.Average(p => p.ElapsedMilliseconds);
-        }
-
-        /// <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;
-
-            if (relativeTo == null)
-                relativeTo = DateTime.UtcNow;
-
-            DateTime start = relativeTo.Value.Subtract(range);
-
-            var entries = this._counter.Where(x => (x.EventTime >= start) && (x.EventTime <= relativeTo)).ToList();
+            endTime ??= DateTime.UtcNow;
+            DateTime startTime = endTime.Value.Subtract(range);
 
-            if (!entries.Any())
-                return 0;
+            double[] entries = this.Entries
+                .Where(entry => entry.EventTime >= startTime && entry.EventTime <= endTime)
+                .Select(p => p.ElapsedMilliseconds)
+                .ToArray();
 
-            return entries.Average(x => x.ElapsedMilliseconds);
+            return entries.Length > 0
+                ? entries.Average()
+                : 0;
         }
     }
 }
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs
index f469eceb..bd13a36e 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterCollection.cs
@@ -2,153 +2,129 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using Cyotek.Collections.Generic;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
     internal class PerformanceCounterCollection
     {
-        /// <summary>The size of the ring buffer.</summary>
-        private const int MAX_ENTRIES = 16384;
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The number of peak invocations to keep.</summary>
+        private readonly int MaxEntries = 16384;
 
-        /// <summary>The list of triggered performance counters.</summary>
+        /// <summary>The sources involved in exceeding alert thresholds.</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;
+        private readonly PerformanceMonitor PerformanceMonitor;
 
-        /// <summary>Holds the time to calculate the average calls per second.</summary>
+        /// <summary>The time to calculate average calls per second.</summary>
         private DateTime CallsPerSecondStart = DateTime.UtcNow;
 
-        /// <summary>The number of invocations of this collection.</summary>
+        /// <summary>The number of invocations.</summary>
         private long CallCount;
 
-        /// <summary>The circular buffer which stores all peak invocations</summary>
-        private readonly CircularBuffer<PeakEntry> PeakInvocations;
+        /// <summary>The peak invocations.</summary>
+        private readonly Stack<PeakEntry> PeakInvocations;
 
+
+        /*********
+        ** Accessors
+        *********/
         /// <summary>The associated performance counters.</summary>
         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>Whether the source is typically invoked at least once per second.</summary>
+        public bool IsPerformanceCritical { get; }
 
         /// <summary>The alert threshold in milliseconds.</summary>
         public double AlertThresholdMilliseconds { get; set; }
 
-        /// <summary>If alerting is enabled or not</summary>
+        /// <summary>Whether alerts are enabled.</summary>
         public bool EnableAlerts { get; set; }
 
 
-        public PerformanceCounterCollection(PerformanceCounterManager performanceCounterManager, string name, bool isImportant)
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="performanceMonitor">The performance counter manager.</param>
+        /// <param name="name">The name of this collection.</param>
+        /// <param name="isPerformanceCritical">Whether the source is typically invoked at least once per second.</param>
+        public PerformanceCounterCollection(PerformanceMonitor performanceMonitor, string name, bool isPerformanceCritical = false)
         {
-            this.PeakInvocations = new CircularBuffer<PeakEntry>(PerformanceCounterCollection.MAX_ENTRIES);
+            this.PeakInvocations = new Stack<PeakEntry>(this.MaxEntries);
             this.Name = name;
-            this.PerformanceCounterManager = performanceCounterManager;
-            this.IsImportant = isImportant;
+            this.PerformanceMonitor = performanceMonitor;
+            this.IsPerformanceCritical = isPerformanceCritical;
         }
 
-        public PerformanceCounterCollection(PerformanceCounterManager performanceCounterManager, string name)
-        {
-            this.PeakInvocations = new CircularBuffer<PeakEntry>(PerformanceCounterCollection.MAX_ENTRIES);
-            this.PerformanceCounterManager = performanceCounterManager;
-            this.Name = name;
-        }
-
-        /// <summary>Tracks a single invocation for a named source.</summary>
+        /// <summary>Track 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)
         {
+            // add entry
             if (!this.PerformanceCounters.ContainsKey(source))
                 this.PerformanceCounters.Add(source, new PerformanceCounter(this, source));
-
             this.PerformanceCounters[source].Add(entry);
 
+            // raise alert
             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());
-        }
-
-        /// <summary>Returns the average execution time for all non-game internal sources.</summary>
+        /// <summary>Get the average execution time for all non-game internal sources in milliseconds.</summary>
         /// <param name="interval">The interval for which to get the average, relative to now</param>
-        /// <returns>The average execution time in milliseconds</returns>
         public double GetModsAverageExecutionTime(TimeSpan interval)
         {
-            return this.PerformanceCounters.Where(p =>
-                p.Key != Constants.GamePerformanceCounterName).Sum(p => p.Value.GetAverage(interval));
-        }
-
-        /// <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());
+            return this.PerformanceCounters
+                .Where(entry => entry.Key != Constants.GamePerformanceCounterName)
+                .Sum(entry => entry.Value.GetAverage(interval));
         }
 
-        /// <summary>Returns the overall average execution time.</summary>
+        /// <summary>Get the overall average execution time in milliseconds.</summary>
         /// <param name="interval">The interval for which to get the average, relative to now</param>
-        /// <returns>The average execution time in milliseconds</returns>
         public double GetAverageExecutionTime(TimeSpan interval)
         {
-            return this.PerformanceCounters.Sum(p => p.Value.GetAverage(interval));
+            return this.PerformanceCounters
+                .Sum(entry => entry.Value.GetAverage(interval));
         }
 
-        /// <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>Returns the average execution time for game-internal sources.</summary>
-        /// <returns>The average execution time in milliseconds</returns>
+        /// <summary>Get the average execution time for game-internal sources in milliseconds.</summary>
         public double GetGameAverageExecutionTime(TimeSpan interval)
         {
-            if (this.PerformanceCounters.TryGetValue(Constants.GamePerformanceCounterName, out PerformanceCounter gameExecTime))
-                return gameExecTime.GetAverage(interval);
-
-            return 0;
+            return this.PerformanceCounters.TryGetValue(Constants.GamePerformanceCounterName, out PerformanceCounter gameExecTime)
+                ? gameExecTime.GetAverage(interval)
+                : 0;
         }
 
-        /// <summary>Returns the peak execution time</summary>
-        /// <param name="interval">The interval for which to get the peak, relative to <paramref name="relativeTo"/></param>
-        /// <param name="relativeTo">The DateTime which the <paramref name="interval"/> is relative to, or DateTime.Now if not given</param>
-        /// <returns>The peak execution time</returns>
-        public double GetPeakExecutionTime(TimeSpan range, DateTime? relativeTo = null)
+        /// <summary>Get the peak execution time in milliseconds.</summary>
+        /// <param name="range">The time range to search.</param>
+        /// <param name="endTime">The end time for the <paramref name="range"/>, or null for the current time.</param>
+        public double GetPeakExecutionTime(TimeSpan range, DateTime? endTime = null)
         {
-            if (this.PeakInvocations.IsEmpty)
+            if (this.PeakInvocations.Count == 0)
                 return 0;
 
-            if (relativeTo == null)
-                relativeTo = DateTime.UtcNow;
-
-            DateTime start = relativeTo.Value.Subtract(range);
-
-            var entries = this.PeakInvocations.Where(x => (x.EventTime >= start) && (x.EventTime <= relativeTo)).ToList();
+            endTime ??= DateTime.UtcNow;
+            DateTime startTime = endTime.Value.Subtract(range);
 
-            if (!entries.Any())
-                return 0;
-
-            return entries.OrderByDescending(x => x.ExecutionTimeMilliseconds).First().ExecutionTimeMilliseconds;
+            return this.PeakInvocations
+                .Where(entry => entry.EventTime >= startTime && entry.EventTime <= endTime)
+                .OrderByDescending(x => x.ExecutionTimeMilliseconds)
+                .Select(p => p.ExecutionTimeMilliseconds)
+                .FirstOrDefault();
         }
 
-        /// <summary>Begins tracking the invocation of this collection.</summary>
+        /// <summary>Start tracking the invocation of this collection.</summary>
         public void BeginTrackInvocation()
         {
             this.TriggeredPerformanceCounters.Clear();
@@ -158,60 +134,58 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
             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>
+        /// <summary>End tracking the invocation of this collection, and raise an alert if needed.</summary>
         public void EndTrackInvocation()
         {
             this.InvocationStopwatch.Stop();
 
-            this.PeakInvocations.Put(
-                new PeakEntry(this.InvocationStopwatch.Elapsed.TotalMilliseconds,
-                    DateTime.UtcNow,
-                    this.TriggeredPerformanceCounters));
-
-            if (!this.EnableAlerts) return;
+            // add invocation
+            if (this.PeakInvocations.Count >= this.MaxEntries)
+                this.PeakInvocations.Pop();
+            this.PeakInvocations.Push(new PeakEntry(this.InvocationStopwatch.Elapsed.TotalMilliseconds, DateTime.UtcNow, this.TriggeredPerformanceCounters.ToArray()));
 
-            if (this.InvocationStopwatch.Elapsed.TotalMilliseconds >= this.AlertThresholdMilliseconds)
-                this.AddAlert(this.InvocationStopwatch.Elapsed.TotalMilliseconds,
-                    this.AlertThresholdMilliseconds, this.TriggeredPerformanceCounters);
+            // raise alert
+            if (this.EnableAlerts && this.InvocationStopwatch.Elapsed.TotalMilliseconds >= this.AlertThresholdMilliseconds)
+                this.AddAlert(this.InvocationStopwatch.Elapsed.TotalMilliseconds, this.AlertThresholdMilliseconds, this.TriggeredPerformanceCounters.ToArray());
         }
 
-        /// <summary>Adds an alert.</summary>
+        /// <summary>Add 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)
+        /// <param name="alerts">The sources involved in exceeding the threshold.</param>
+        public void AddAlert(double executionTimeMilliseconds, double thresholdMilliseconds, AlertContext[] alerts)
         {
-            this.PerformanceCounterManager.AddAlert(new AlertEntry(this, executionTimeMilliseconds,
-                thresholdMilliseconds, alerts));
+            this.PerformanceMonitor.AddAlert(
+                new AlertEntry(this, executionTimeMilliseconds, thresholdMilliseconds, alerts)
+            );
         }
 
-        /// <summary>Adds an alert for a single AlertContext</summary>
+        /// <summary>Add an alert.</summary>
         /// <param name="executionTimeMilliseconds">The execution time in milliseconds.</param>
         /// <param name="thresholdMilliseconds">The configured threshold.</param>
-        /// <param name="alert">The context</param>
+        /// <param name="alert">The source involved in exceeding the threshold.</param>
         public void AddAlert(double executionTimeMilliseconds, double thresholdMilliseconds, AlertContext alert)
         {
-            this.AddAlert(executionTimeMilliseconds, thresholdMilliseconds, new List<AlertContext>() {alert});
+            this.AddAlert(executionTimeMilliseconds, thresholdMilliseconds, new[] { alert });
         }
 
-        /// <summary>Resets the calls per second counter.</summary>
+        /// <summary>Reset the calls per second counter.</summary>
         public void ResetCallsPerSecond()
         {
             this.CallCount = 0;
             this.CallsPerSecondStart = DateTime.UtcNow;
         }
 
-        /// <summary>Resets all performance counters in this collection.</summary>
+        /// <summary>Reset all performance counters in this collection.</summary>
         public void Reset()
         {
             this.PeakInvocations.Clear();
-            foreach (var i in this.PerformanceCounters)
-                i.Value.Reset();
+            foreach (var counter in this.PerformanceCounters)
+                counter.Value.Reset();
         }
 
-        /// <summary>Resets the performance counter for a specific source.</summary>
-        /// <param name="source">The source name</param>
+        /// <summary>Reset 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)
@@ -219,15 +193,13 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
                     i.Value.Reset();
         }
 
-        /// <summary>Returns the average calls per second.</summary>
-        /// <returns>The average calls per second.</returns>
+        /// <summary>Get the average calls per second.</summary>
         public long GetAverageCallsPerSecond()
         {
-            long runtimeInSeconds = (long) DateTime.UtcNow.Subtract(this.CallsPerSecondStart).TotalSeconds;
-
-            if (runtimeInSeconds == 0) return 0;
-
-            return this.CallCount / runtimeInSeconds;
+            long runtimeInSeconds = (long)DateTime.UtcNow.Subtract(this.CallsPerSecondStart).TotalSeconds;
+            return runtimeInSeconds > 0
+                ? this.CallCount / runtimeInSeconds
+                : 0;
         }
     }
 }
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs
index a50fce7d..a1d78fc8 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterEntry.cs
@@ -2,13 +2,29 @@ using System;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
-    /// <summary>A single performance counter entry. Records the DateTime of the event and the elapsed millisecond.</summary>
+    /// <summary>A single performance counter entry.</summary>
     internal struct PerformanceCounterEntry
     {
-        /// <summary>The DateTime when the entry occured.</summary>
-        public DateTime EventTime;
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>When the entry occurred.</summary>
+        public DateTime EventTime { get; }
 
-        /// <summary>The elapsed milliseconds</summary>
-        public double ElapsedMilliseconds;
+        /// <summary>The elapsed milliseconds.</summary>
+        public double ElapsedMilliseconds { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="eventTime">When the entry occurred.</param>
+        /// <param name="elapsedMilliseconds">The elapsed milliseconds.</param>
+        public PerformanceCounterEntry(DateTime eventTime, double elapsedMilliseconds)
+        {
+            this.EventTime = eventTime;
+            this.ElapsedMilliseconds = elapsedMilliseconds;
+        }
     }
 }
diff --git a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs
index bd964442..81e4e468 100644
--- a/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs
+++ b/src/SMAPI/Framework/PerformanceCounter/PerformanceCounterManager.cs
@@ -7,12 +7,14 @@ using StardewModdingAPI.Framework.Events;
 
 namespace StardewModdingAPI.Framework.PerformanceCounter
 {
-    internal class PerformanceCounterManager
+    /// <summary>Tracks performance metrics.</summary>
+    internal class PerformanceMonitor
     {
-        public HashSet<PerformanceCounterCollection> PerformanceCounterCollections = new HashSet<PerformanceCounterCollection>();
-
+        /*********
+        ** Fields
+        *********/
         /// <summary>The recorded alerts.</summary>
-        private readonly List<AlertEntry> Alerts = new List<AlertEntry>();
+        private readonly IList<AlertEntry> Alerts = new List<AlertEntry>();
 
         /// <summary>The monitor for output logging.</summary>
         private readonly IMonitor Monitor;
@@ -20,62 +22,64 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
         /// <summary>The invocation stopwatch.</summary>
         private readonly Stopwatch InvocationStopwatch = new Stopwatch();
 
-        /// <summary>Specifies if alerts should be paused.</summary>
+        /// <summary>The underlying performance counter collections.</summary>
+        private readonly IDictionary<string, PerformanceCounterCollection> Collections = new Dictionary<string, PerformanceCounterCollection>(StringComparer.InvariantCultureIgnoreCase);
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>Whether alerts are paused.</summary>
         public bool PauseAlerts { get; set; }
 
-        /// <summary>Specifies if performance counter tracking should be enabled.</summary>
+        /// <summary>Whether performance counter tracking is enabled.</summary>
         public bool EnableTracking { get; set; }
 
-        /// <summary>Constructs a performance counter manager.</summary>
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
         /// <param name="monitor">The monitor for output logging.</param>
-        public PerformanceCounterManager(IMonitor monitor)
+        public PerformanceMonitor(IMonitor monitor)
         {
             this.Monitor = monitor;
         }
 
-        /// <summary>Resets all performance counters in all collections.</summary>
+        /// <summary>Reset all performance counters in all collections.</summary>
         public void Reset()
         {
-            foreach (PerformanceCounterCollection collection in this.PerformanceCounterCollections)
-            {
+            foreach (PerformanceCounterCollection collection in this.Collections.Values)
                 collection.Reset();
-            }
-
-            foreach (var eventPerformanceCounter in
-                this.PerformanceCounterCollections.SelectMany(performanceCounter => performanceCounter.PerformanceCounters))
-            {
-                eventPerformanceCounter.Value.Reset();
-            }
         }
 
-        /// <summary>Begins tracking the invocation for a collection.</summary>
-        /// <param name="collectionName">The collection name</param>
-        public void BeginTrackInvocation(string collectionName)
+        /// <summary>Track the invocation time for a collection.</summary>
+        /// <param name="collectionName">The name of the collection.</param>
+        /// <param name="action">The action to execute and track.</param>
+        public void Track(string collectionName, Action action)
         {
             if (!this.EnableTracking)
             {
+                action();
                 return;
             }
 
-            this.GetOrCreateCollectionByName(collectionName).BeginTrackInvocation();
-        }
-
-        /// <summary>Ends tracking the invocation for a collection.</summary>
-        /// <param name="collectionName"></param>
-        public void EndTrackInvocation(string collectionName)
-        {
-            if (!this.EnableTracking)
+            PerformanceCounterCollection collection = this.GetOrCreateCollectionByName(collectionName);
+            collection.BeginTrackInvocation();
+            try
             {
-                return;
+                action();
+            }
+            finally
+            {
+                collection.EndTrackInvocation();
             }
-
-            this.GetOrCreateCollectionByName(collectionName).EndTrackInvocation();
         }
 
-        /// <summary>Tracks a single performance counter invocation in a specific collection.</summary>
+        /// <summary>Track 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>
+        /// <param name="action">The action to execute and track.</param>
         public void Track(string collectionName, string sourceName, Action action)
         {
             if (!this.EnableTracking)
@@ -84,6 +88,7 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
                 return;
             }
 
+            PerformanceCounterCollection collection = this.GetOrCreateCollectionByName(collectionName);
             DateTime eventTime = DateTime.UtcNow;
             this.InvocationStopwatch.Reset();
             this.InvocationStopwatch.Start();
@@ -95,79 +100,50 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
             finally
             {
                 this.InvocationStopwatch.Stop();
-
-                this.GetOrCreateCollectionByName(collectionName).Track(sourceName, new PerformanceCounterEntry
-                {
-                    EventTime = eventTime,
-                    ElapsedMilliseconds = this.InvocationStopwatch.Elapsed.TotalMilliseconds
-                });
+                collection.Track(sourceName, new PerformanceCounterEntry(eventTime, this.InvocationStopwatch.Elapsed.TotalMilliseconds));
             }
         }
 
-        /// <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);
-        }
-
-        /// <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) return collection;
-
-            collection = new PerformanceCounterCollection(this, name);
-            this.PerformanceCounterCollections.Add(collection);
-
-            return collection;
-        }
-
-        /// <summary>Resets the performance counters for a specific collection.</summary>
+        /// <summary>Reset the performance counters for a specific collection.</summary>
         /// <param name="name">The collection name.</param>
         public void ResetCollection(string name)
         {
-            foreach (PerformanceCounterCollection performanceCounterCollection in
-                this.PerformanceCounterCollections.Where(performanceCounterCollection =>
-                    performanceCounterCollection.Name.Equals(name, StringComparison.InvariantCultureIgnoreCase)))
+            if (this.Collections.TryGetValue(name, out PerformanceCounterCollection collection))
             {
-                performanceCounterCollection.ResetCallsPerSecond();
-                performanceCounterCollection.Reset();
+                collection.ResetCallsPerSecond();
+                collection.Reset();
             }
         }
 
-        /// <summary>Resets performance counters for a specific source.</summary>
+        /// <summary>Reset performance counters for a specific source.</summary>
         /// <param name="name">The name of the source.</param>
         public void ResetSource(string name)
         {
-            foreach (PerformanceCounterCollection performanceCounterCollection in this.PerformanceCounterCollections)
+            foreach (PerformanceCounterCollection performanceCounterCollection in this.Collections.Values)
                 performanceCounterCollection.ResetSource(name);
         }
 
         /// <summary>Print any queued alerts.</summary>
         public void PrintQueuedAlerts()
         {
-            if (this.Alerts.Count == 0) return;
+            if (this.Alerts.Count == 0)
+                return;
 
-            StringBuilder sb = new StringBuilder();
+            StringBuilder report = new StringBuilder();
 
             foreach (AlertEntry alert in this.Alerts)
             {
-                sb.AppendLine($"{alert.Collection.Name} took {alert.ExecutionTimeMilliseconds:F2}ms (exceeded threshold of {alert.ThresholdMilliseconds:F2}ms)");
+                report.AppendLine($"{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());
+                    report.AppendLine(context.ToString());
             }
 
             this.Alerts.Clear();
-            this.Monitor.Log(sb.ToString(), LogLevel.Error);
+            this.Monitor.Log(report.ToString(), LogLevel.Error);
         }
 
-        /// <summary>Adds an alert to the queue.</summary>
+        /// <summary>Add an alert to the queue.</summary>
         /// <param name="entry">The alert to add.</param>
         public void AddAlert(AlertEntry entry)
         {
@@ -175,68 +151,34 @@ namespace StardewModdingAPI.Framework.PerformanceCounter
                 this.Alerts.Add(entry);
         }
 
-        /// <summary>Initialized the default performance counter collections.</summary>
+        /// <summary>Initialize the default performance counter collections.</summary>
         /// <param name="eventManager">The event manager.</param>
         public void InitializePerformanceCounterCollections(EventManager eventManager)
         {
-            this.PerformanceCounterCollections = new HashSet<PerformanceCounterCollection>()
+            foreach (IManagedEvent @event in eventManager.GetAllEvents())
+                this.Collections[@event.EventName] = new PerformanceCounterCollection(this, @event.EventName, @event.IsPerformanceCritical);
+        }
+
+        /// <summary>Get the underlying performance counters.</summary>
+        public IEnumerable<PerformanceCounterCollection> GetCollections()
+        {
+            return this.Collections.Values;
+        }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get a collection by name and creates it if it doesn't exist.</summary>
+        /// <param name="name">The name of the collection.</param>
+        private PerformanceCounterCollection GetOrCreateCollectionByName(string name)
+        {
+            if (!this.Collections.TryGetValue(name, out PerformanceCounterCollection collection))
             {
-                new EventPerformanceCounterCollection(this, eventManager.MenuChanged, false),
-
-                // Rendering Events
-                new EventPerformanceCounterCollection(this, eventManager.Rendering, false),
-                new EventPerformanceCounterCollection(this, eventManager.Rendered, true),
-                new EventPerformanceCounterCollection(this, eventManager.RenderingWorld, false),
-                new EventPerformanceCounterCollection(this, eventManager.RenderedWorld, true),
-                new EventPerformanceCounterCollection(this, eventManager.RenderingActiveMenu, false),
-                new EventPerformanceCounterCollection(this, eventManager.RenderedActiveMenu, true),
-                new EventPerformanceCounterCollection(this, eventManager.RenderingHud, false),
-                new EventPerformanceCounterCollection(this, eventManager.RenderedHud, true),
-
-                new EventPerformanceCounterCollection(this, eventManager.WindowResized, false),
-                new EventPerformanceCounterCollection(this, eventManager.GameLaunched, false),
-                new EventPerformanceCounterCollection(this, eventManager.UpdateTicking, true),
-                new EventPerformanceCounterCollection(this, eventManager.UpdateTicked, true),
-                new EventPerformanceCounterCollection(this, eventManager.OneSecondUpdateTicking, true),
-                new EventPerformanceCounterCollection(this, eventManager.OneSecondUpdateTicked, true),
-
-                new EventPerformanceCounterCollection(this, eventManager.SaveCreating, false),
-                new EventPerformanceCounterCollection(this, eventManager.SaveCreated, false),
-                new EventPerformanceCounterCollection(this, eventManager.Saving, false),
-                new EventPerformanceCounterCollection(this, eventManager.Saved, false),
-
-                new EventPerformanceCounterCollection(this, eventManager.DayStarted, false),
-                new EventPerformanceCounterCollection(this, eventManager.DayEnding, false),
-
-                new EventPerformanceCounterCollection(this, eventManager.TimeChanged, true),
-
-                new EventPerformanceCounterCollection(this, eventManager.ReturnedToTitle, false),
-
-                new EventPerformanceCounterCollection(this, eventManager.ButtonPressed, true),
-                new EventPerformanceCounterCollection(this, eventManager.ButtonReleased, true),
-                new EventPerformanceCounterCollection(this, eventManager.CursorMoved, true),
-                new EventPerformanceCounterCollection(this, eventManager.MouseWheelScrolled, 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, false),
-                new EventPerformanceCounterCollection(this, eventManager.Warped, false),
-
-                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, false),
-                new EventPerformanceCounterCollection(this, eventManager.ObjectListChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.ChestInventoryChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.TerrainFeatureListChanged, true),
-                new EventPerformanceCounterCollection(this, eventManager.LoadStageChanged, false),
-                new EventPerformanceCounterCollection(this, eventManager.UnvalidatedUpdateTicking, false),
-                new EventPerformanceCounterCollection(this, eventManager.UnvalidatedUpdateTicked, false),
-            };
+                collection = new PerformanceCounterCollection(this, name);
+                this.Collections[name] = collection;
+            }
+            return collection;
         }
     }
 }
diff --git a/src/SMAPI/Framework/SCore.cs b/src/SMAPI/Framework/SCore.cs
index af7513e3..ac89587e 100644
--- a/src/SMAPI/Framework/SCore.cs
+++ b/src/SMAPI/Framework/SCore.cs
@@ -23,6 +23,7 @@ using StardewModdingAPI.Framework.Models;
 using StardewModdingAPI.Framework.ModHelpers;
 using StardewModdingAPI.Framework.ModLoading;
 using StardewModdingAPI.Framework.Patching;
+using StardewModdingAPI.Framework.PerformanceCounter;
 using StardewModdingAPI.Framework.Reflection;
 using StardewModdingAPI.Framework.Serialization;
 using StardewModdingAPI.Patches;
@@ -33,7 +34,6 @@ using StardewModdingAPI.Toolkit.Serialization;
 using StardewModdingAPI.Toolkit.Utilities;
 using StardewValley;
 using Object = StardewValley.Object;
-using PerformanceCounterManager = StardewModdingAPI.Framework.PerformanceCounter.PerformanceCounterManager;
 using ThreadState = System.Threading.ThreadState;
 
 namespace StardewModdingAPI.Framework
@@ -135,8 +135,8 @@ namespace StardewModdingAPI.Framework
         internal static DeprecationManager DeprecationManager { get; private set; }
 
         /// <summary>Manages performance counters.</summary>
-        /// <remarks>This is initialized after the game starts. This is accessed directly because it's not part of the normal class model.</remarks>
-        internal static PerformanceCounterManager PerformanceCounterManager { get; private set; }
+        /// <remarks>This is initialized after the game starts. This is non-private for use by Console Commands.</remarks>
+        internal static PerformanceMonitor PerformanceMonitor { get; private set; }
 
 
         /*********
@@ -167,9 +167,9 @@ namespace StardewModdingAPI.Framework
             };
             this.MonitorForGame = this.GetSecondaryMonitor("game");
 
-            SCore.PerformanceCounterManager = new PerformanceCounterManager(this.Monitor);
-            this.EventManager = new EventManager(this.Monitor, this.ModRegistry, SCore.PerformanceCounterManager);
-            SCore.PerformanceCounterManager.InitializePerformanceCounterCollections(this.EventManager);
+            SCore.PerformanceMonitor = new PerformanceMonitor(this.Monitor);
+            this.EventManager = new EventManager(this.Monitor, this.ModRegistry, SCore.PerformanceMonitor);
+            SCore.PerformanceMonitor.InitializePerformanceCounterCollections(this.EventManager);
 
             SCore.DeprecationManager = new DeprecationManager(this.Monitor, this.ModRegistry);
 
@@ -248,7 +248,7 @@ namespace StardewModdingAPI.Framework
                     jsonHelper: this.Toolkit.JsonHelper,
                     modRegistry: this.ModRegistry,
                     deprecationManager: SCore.DeprecationManager,
-                    performanceCounterManager: SCore.PerformanceCounterManager,
+                    performanceMonitor: SCore.PerformanceMonitor,
                     onGameInitialized: this.InitializeAfterGameStart,
                     onGameExiting: this.Dispose,
                     cancellationToken: this.CancellationToken,
@@ -1307,6 +1307,7 @@ namespace StardewModdingAPI.Framework
                     this.ReloadTranslations(this.ModRegistry.GetAll(contentPacks: false));
                     this.Monitor.Log("Reloaded translation files for all mods. This only affects new translations the mods fetch; if they cached some text, it may not be updated.", LogLevel.Info);
                     break;
+
                 default:
                     throw new NotSupportedException($"Unrecognized core SMAPI command '{name}'.");
             }
diff --git a/src/SMAPI/Framework/SGame.cs b/src/SMAPI/Framework/SGame.cs
index 266e2e6f..352859ec 100644
--- a/src/SMAPI/Framework/SGame.cs
+++ b/src/SMAPI/Framework/SGame.cs
@@ -59,7 +59,8 @@ namespace StardewModdingAPI.Framework
         /// <summary>Manages deprecation warnings.</summary>
         private readonly DeprecationManager DeprecationManager;
 
-        private readonly PerformanceCounterManager PerformanceCounterManager;
+        /// <summary>Tracks performance metrics.</summary>
+        private readonly PerformanceMonitor PerformanceMonitor;
 
         /// <summary>The maximum number of consecutive attempts SMAPI should make to recover from a draw error.</summary>
         private readonly Countdown DrawCrashTimer = new Countdown(60); // 60 ticks = roughly one second
@@ -155,12 +156,12 @@ namespace StardewModdingAPI.Framework
         /// <param name="jsonHelper">Encapsulates SMAPI's JSON file parsing.</param>
         /// <param name="modRegistry">Tracks the installed mods.</param>
         /// <param name="deprecationManager">Manages deprecation warnings.</param>
-        /// <param name="performanceCounterManager">Manages performance monitoring.</param>
+        /// <param name="performanceMonitor">Tracks performance metrics.</param>
         /// <param name="onGameInitialized">A callback to invoke after the game finishes initializing.</param>
         /// <param name="onGameExiting">A callback to invoke when the game exits.</param>
         /// <param name="cancellationToken">Propagates notification that SMAPI should exit.</param>
         /// <param name="logNetworkTraffic">Whether to log network traffic.</param>
-        internal SGame(Monitor monitor, IMonitor monitorForGame, Reflector reflection, Translator translator, EventManager eventManager, JsonHelper jsonHelper, ModRegistry modRegistry, DeprecationManager deprecationManager, PerformanceCounterManager performanceCounterManager, Action onGameInitialized, Action onGameExiting, CancellationTokenSource cancellationToken, bool logNetworkTraffic)
+        internal SGame(Monitor monitor, IMonitor monitorForGame, Reflector reflection, Translator translator, EventManager eventManager, JsonHelper jsonHelper, ModRegistry modRegistry, DeprecationManager deprecationManager, PerformanceMonitor performanceMonitor, Action onGameInitialized, Action onGameExiting, CancellationTokenSource cancellationToken, bool logNetworkTraffic)
         {
             this.OnLoadingFirstAsset = SGame.ConstructorHack.OnLoadingFirstAsset;
             SGame.ConstructorHack = null;
@@ -180,7 +181,7 @@ namespace StardewModdingAPI.Framework
             this.Reflection = reflection;
             this.Translator = translator;
             this.DeprecationManager = deprecationManager;
-            this.PerformanceCounterManager = performanceCounterManager;
+            this.PerformanceMonitor = performanceMonitor;
             this.OnGameInitialized = onGameInitialized;
             this.OnGameExiting = onGameExiting;
             Game1.input = new SInputState();
@@ -312,7 +313,7 @@ namespace StardewModdingAPI.Framework
             try
             {
                 this.DeprecationManager.PrintQueued();
-                this.PerformanceCounterManager.PrintQueuedAlerts();
+                this.PerformanceMonitor.PrintQueuedAlerts();
 
                 /*********
                 ** First-tick initialization