每列单例 watcher， O(columns)订阅，降低峰值GC，但invalidation显著升高，整体愿意接受

osu.Game.Benchmarks/BenchmarkHitObject.cs

@@ -11,7 +11,7 @@ namespace osu.Game.Benchmarks
 {
     public class BenchmarkHitObject : BenchmarkTest
     {
-        [Params(1, 100, 1000)]
+        [Params(1, 1000, 5000)]
         public int Count { get; set; }
 
         [Params(false, true)]

osu.Game.Rulesets.Mania/Skinning/Ez2/Ez2HitExplosion.cs

@@ -73,7 +73,8 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
             direction.BindTo(scrollingInfo.Direction);
             direction.BindValueChanged(onDirectionChanged, true);
 
-            accentColour = column.AccentColour.GetBoundCopy();
+            // Use shared column bindable to prevent per-instance allocation via GetBoundCopy().
+            accentColour = column.AccentColour;
             accentColour.BindValueChanged(colour =>
             {
                 largeFaint.Colour = Interpolation.ValueAt(0.8f, colour.NewValue, Color4.White, 0, 1);

osu.Game.Rulesets.Mania/Skinning/Ez2/Ez2KeyArea.cs

@@ -35,6 +35,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
         private Circle hitTargetLine = null!;
 
         private CircularContainer? topIcon;
+        private Box? topIconBox;
         private Bindable<Color4> accentColour = null!;
 
         [Resolved]
@@ -123,7 +124,8 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
             direction.BindTo(scrollingInfo.Direction);
             direction.BindValueChanged(onDirectionChanged, true);
 
-            accentColour = column.AccentColour.GetBoundCopy();
+            // Use the column's shared bindable to avoid per-instance allocations from GetBoundCopy()
+            accentColour = column.AccentColour;
             accentColour.BindValueChanged(colour =>
                 {
                     background.Colour = colour.NewValue.Darken(0.2f);
@@ -142,13 +144,15 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
 
             double bpm = beatmap.BeatmapInfo.BPM * gameplayClock.GetTrueGameplayRate();
             beatInterval = 60000 / bpm;
+            // cache reference to inner box to avoid LINQ allocations during Update
+            topIconBox = topIcon?.Children.OfType<Box>().FirstOrDefault();
         }
 
         protected override void Update()
         {
             base.Update();
 
-            if (topIcon == null || !topIcon.Children.Any())
+            if (topIconBox == null)
                 return;
 
             double progress = (gameplayClock.CurrentTime % beatInterval) / beatInterval;
@@ -156,7 +160,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
             if (progress < gameplayClock.ElapsedFrameTime / beatInterval)
             {
                 double fadeTime = Math.Max(1, beatInterval / 2);
-                var box = topIcon.Children.OfType<Box>().FirstOrDefault();
+                var box = topIconBox;
 
                 box?.FadeTo(1, fadeTime)
                    .Then()

osu.Game.Rulesets.Mania/Skinning/Ez2/Ez2KeyAreaPlus.cs

@@ -34,6 +34,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
 
         private Container<Circle> bottomIcon = null!;
         private CircularContainer topIcon = null!;
+        private Box? topIconBox;
         private Bindable<Color4> accentColour = null!;
 
         [Resolved]
@@ -162,12 +163,15 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
 
             // double bpm = beatmap.BeatmapInfo.BPM;
             double bpm = beatmap.ControlPointInfo.TimingPointAt(gameplayClock.CurrentTime).BPM * gameplayClock.GetTrueGameplayRate();
-            applyBlinkingEffect(topIcon, bpm);
+            // cache inner box once to avoid repeated LINQ allocation inside scheduled callback
+            topIconBox = topIcon.Children.OfType<Box>().FirstOrDefault();
+            applyBlinkingEffect(topIconBox, bpm);
 
             direction.BindTo(scrollingInfo.Direction);
             direction.BindValueChanged(onDirectionChanged, true);
 
-            accentColour = column.AccentColour.GetBoundCopy();
+            // Use the column's shared bindable to avoid per-instance allocations from GetBoundCopy()
+            accentColour = column.AccentColour;
             accentColour.BindValueChanged(colour =>
                 {
                     background.Colour = colour.NewValue.Darken(0.2f);
@@ -178,13 +182,15 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
             column.TopLevelContainer.Add(CreateProxy());
         }
 
-        private void applyBlinkingEffect(CircularContainer container, double bpm)
+        private void applyBlinkingEffect(Box? box, double bpm)
         {
+            if (box == null) return;
+
             double interval = 60000 / bpm;
 
             Scheduler.AddDelayed(() =>
             {
-                container.Children.OfType<Box>().First().FadeTo(1, interval / 2).Then().FadeTo(0, interval / 2);
+                box.FadeTo(1, interval / 2).Then().FadeTo(0, interval / 2);
             }, interval, true);
         }
 

osu.Game.Rulesets.Mania/Skinning/Ez2/Ez2NotePiece.cs

@@ -27,6 +27,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
         private readonly IBindable<Color4> accentColour = new Bindable<Color4>();
 
         private readonly Circle colouredBox;
+        private Drawable iconContainer = null!;
 
         public Ez2NotePiece()
         {
@@ -35,6 +36,8 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
             CornerRadius = CORNER_RADIUS;
             // Masking = true;
 
+            iconContainer = CreateIcon();
+
             InternalChildren = new[]
             {
                 new Container
@@ -83,7 +86,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
                     RelativeSizeAxes = Axes.X,
                     Height = 0,
                 },
-                CreateIcon(),
+                iconContainer,
             };
         }
 
@@ -99,7 +102,8 @@ namespace osu.Game.Rulesets.Mania.Skinning.Ez2
             // NoteHeight = (float)config.Get<double>(ManiaRulesetSetting.ColumnWidth);
             // specialFactor = (float)config.Get<double>(ManiaRulesetSetting.SpecialFactor);
 
-            CreateIcon().Size = new Vector2(DrawWidth / NoteHeight * 0.7f);
+            if (iconContainer != null)
+                iconContainer.Size = new Vector2(DrawWidth / NoteHeight * 0.7f);
         }
 
         protected virtual Drawable CreateIcon() => new Container

osu.Game.Rulesets.Mania/Skinning/EzStylePro/EzColumnBackground.cs

@@ -87,7 +87,8 @@ namespace osu.Game.Rulesets.Mania.Skinning.EzStylePro
             // 计算 drawSeparator 结果（基于不变的列数和列索引）
             shouldDrawSeparator = drawSeparatorImpl(Column.Index, stageDefinition);
 
-            accentColour = new Bindable<Color4>(ezSkinConfig.GetColumnColor(stageDefinition.Columns, Column.Index));
+            // 使用 Column 提供的共享 bindable，避免为每个列背景构建新的 Bindable 实例
+            accentColour = Column.AccentColour;
             accentColour.BindValueChanged(colour =>
             {
                 var baseCol = colour.NewValue;
@@ -104,7 +105,18 @@ namespace osu.Game.Rulesets.Mania.Skinning.EzStylePro
         {
             base.LoadComplete();
 
-            if (Column.BackgroundContainer.Children.OfType<Box>().All(b => b.Name != "Separator"))
+            bool hasSeparator = false;
+
+            foreach (var child in Column.BackgroundContainer.Children)
+            {
+                if (child is Box b && b.Name == "Separator")
+                {
+                    hasSeparator = true;
+                    break;
+                }
+            }
+
+            if (!hasSeparator)
                 Column.BackgroundContainer.Add(separator);
 
             if (!Column.BackgroundContainer.Children.Contains(hitOverlay))

osu.Game.Rulesets.Mania/Skinning/EzStylePro/EzNoteBase.cs

@@ -1,6 +1,9 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -101,9 +104,8 @@ namespace osu.Game.Rulesets.Mania.Skinning.EzStylePro
             NoteSetName = Column.NoteSetBindable;
             NoteSize = Column.NoteSizeBindable;
 
-            Column.NoteSetChanged += OnNoteSetChanged;
+            // Use a per-column watcher to avoid creating an event handler delegate per-note.
-            Column.NoteColourChanged += OnColourChanged;
+            ColumnWatcher.GetOrCreate(Column).Add(this);
-            Column.NoteSizeChanged += OnNoteSizeChanged;
 
             UpdateSize();
         }
@@ -153,7 +155,6 @@ namespace osu.Game.Rulesets.Mania.Skinning.EzStylePro
                         sideLine.UpdateGlowEffect(NoteColor);
                 }
             }
-
         }
 
         private void OnColourChanged()
@@ -197,13 +198,122 @@ namespace osu.Game.Rulesets.Mania.Skinning.EzStylePro
         {
             if (isDisposing)
             {
-                Column.NoteSetChanged -= OnNoteSetChanged;
+                ColumnWatcher.Remove(Column, this);
-                Column.NoteColourChanged -= OnColourChanged;
-                Column.NoteSizeChanged -= OnNoteSizeChanged;
             }
 
             base.Dispose(isDisposing);
         }
+
+        // Forwarders used by ColumnWatcher when broadcasting per-column changes to instances.
+        internal void ForwardOnNoteSetChanged(ValueChangedEvent<string> e) => OnNoteSetChanged(e);
+        internal void ForwardOnColourChanged() => OnColourChanged();
+        internal void ForwardOnNoteSizeChanged() => OnNoteSizeChanged();
+
+        private class ColumnWatcher
+        {
+            private readonly Column column;
+            private readonly List<WeakReference<EzNoteBase>> notes = new List<WeakReference<EzNoteBase>>();
+
+            public ColumnWatcher(Column column)
+            {
+                this.column = column;
+                column.NoteSetChanged += onNoteSetChanged;
+                column.NoteColourChanged += onNoteColourChanged;
+                column.NoteSizeChanged += onNoteSizeChanged;
+            }
+
+            public void Add(EzNoteBase note)
+            {
+                // store weak reference to avoid preventing note GC if removed elsewhere
+                notes.Add(new WeakReference<EzNoteBase>(note));
+            }
+
+            public void Remove(EzNoteBase note)
+            {
+                notes.RemoveAll(wr => !wr.TryGetTarget(out var target) || ReferenceEquals(target, note));
+            }
+
+            private void onNoteSetChanged(ValueChangedEvent<string> e)
+            {
+                // iterate backwards and remove dead weak references in-place to avoid
+                // allocating a large temporary array when the column has many notes.
+                for (int i = notes.Count - 1; i >= 0; i--)
+                {
+                    var wr = notes[i];
+                    if (wr.TryGetTarget(out var target))
+                        target.ForwardOnNoteSetChanged(e);
+                    else
+                        notes.RemoveAt(i);
+                }
+            }
+
+            private void onNoteColourChanged()
+            {
+                for (int i = notes.Count - 1; i >= 0; i--)
+                {
+                    var wr = notes[i];
+                    if (wr.TryGetTarget(out var target))
+                        target.ForwardOnColourChanged();
+                    else
+                        notes.RemoveAt(i);
+                }
+            }
+
+            private void onNoteSizeChanged()
+            {
+                for (int i = notes.Count - 1; i >= 0; i--)
+                {
+                    var wr = notes[i];
+                    if (wr.TryGetTarget(out var target))
+                        target.ForwardOnNoteSizeChanged();
+                    else
+                        notes.RemoveAt(i);
+                }
+            }
+
+            public void Unsubscribe()
+            {
+                column.NoteSetChanged -= onNoteSetChanged;
+                column.NoteColourChanged -= onNoteColourChanged;
+                column.NoteSizeChanged -= onNoteSizeChanged;
+            }
+
+            public bool IsEmpty => notes.All(wr => !wr.TryGetTarget(out _));
+
+            private static readonly Dictionary<Column, ColumnWatcher> watchers = new Dictionary<Column, ColumnWatcher>();
+            private static readonly object watcher_lock = new object();
+
+            public static ColumnWatcher GetOrCreate(Column c)
+            {
+                lock (watcher_lock)
+                {
+                    if (!watchers.TryGetValue(c, out var w))
+                    {
+                        w = new ColumnWatcher(c);
+                        watchers[c] = w;
+                    }
+
+                    return w;
+                }
+            }
+
+            public static void Remove(Column c, EzNoteBase note)
+            {
+                lock (watcher_lock)
+                {
+                    if (!watchers.TryGetValue(c, out var w))
+                        return;
+
+                    w.Remove(note);
+
+                    if (w.IsEmpty)
+                    {
+                        w.Unsubscribe();
+                        watchers.Remove(c);
+                    }
+                }
+            }
+        }
     }
 }
 

osu.sln

@@ -128,7 +128,6 @@ Global
 		{F5037F74-E137-4940-8CE7-4D3E5DF0FB39}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F5037F74-E137-4940-8CE7-4D3E5DF0FB39}.Release|Any CPU.Build.0 = Release|Any CPU
 		{5672CA4D-1B37-425B-A118-A8DA26E78938}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{5672CA4D-1B37-425B-A118-A8DA26E78938}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{5672CA4D-1B37-425B-A118-A8DA26E78938}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{5672CA4D-1B37-425B-A118-A8DA26E78938}.Release|Any CPU.Build.0 = Release|Any CPU
 		{5672CA4D-1B37-425B-A118-A8DA26E78938}.Release|Any CPU.Deploy.0 = Release|Any CPU
@@ -136,9 +135,7 @@ Global
 		{E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Release|Any CPU.Build.0 = Release|Any CPU
 		{E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Release|Any CPU.Deploy.0 = Release|Any CPU
 		{E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Debug|Any CPU.Build.0 = Debug|Any CPU
         {E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-        {E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Debug|Any CPU.Build.0 = Debug|Any CPU
         {E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Release|Any CPU.ActiveCfg = Release|Any CPU
         {E8F3B2C4-9D7A-4E6B-8C2F-7A9B12345678}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection