perf: second-pass hot-path audit — MathF, DimmablePieces cache, Taiko loop

osu.Android/AndroidBackgroundDataStoreProcessor.cs

@@ -0,0 +1,27 @@
+// 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 osu.Game.Database;
+
+namespace osu.Android
+{
+    /// <summary>
+    /// Android-specific <see cref="BackgroundDataStoreProcessor"/> that extends the sleep
+    /// interval during active gameplay from the default 30 s to 2 minutes.
+    /// </summary>
+    /// <remarks>
+    /// On Android the high-performance session (<see cref="Performance.AndroidHighPerformanceSessionManager"/>)
+    /// flips <c>GCSettings.LatencyMode</c> to <c>SustainedLowLatency</c> for the entire gameplay window,
+    /// which suppresses Gen-2 (major) GC collections.  The background processor's sleep loop also
+    /// suspends during gameplay, but wakes every <see cref="BackgroundDataStoreProcessor.TimeToSleepDuringGameplay"/>
+    /// ms to re-check the condition.  Each wake-up incurs a managed thread resume + lock acquisition,
+    /// generating a small burst of GC-visible allocations.  At 30 s those spurious wakes happen ~10×
+    /// per typical 5-minute play session; at 120 s they drop to ~2×, cutting the associated
+    /// allocation pressure and the risk of a GC stall at the worst possible moment.
+    /// </remarks>
+    public class AndroidBackgroundDataStoreProcessor : BackgroundDataStoreProcessor
+    {
+        // 2-minute polling interval while gameplay is active (vs. the default 30 s).
+        protected override int TimeToSleepDuringGameplay => 120_000;
+    }
+}

osu.Android/Native/oboe_bridge.cpp

@@ -97,9 +97,28 @@ bool OboeBridge::open(int32_t sampleRate) {
     // MMAP provides direct access to audio hardware buffers, shaving ~1-2ms off latency.
     oboe::OboeExtensions::setMMapEnabled(true);
 
-    // Initialise StabilizedCallback to even out callback execution time.
-    // shared_ptr is used to satisfy the non-deprecated setDataCallback overload.
-    stabilizedCallback_ = std::make_shared<oboe::StabilizedCallback>(this);
+    // Non-owning shared_ptr for error callback — OboeBridge outlives the stream.
+    auto errorCb = std::shared_ptr<oboe::AudioStreamErrorCallback>(
+        std::shared_ptr<void>(), static_cast<oboe::AudioStreamErrorCallback*>(this));
+
+    // -----------------------------------------------------------------------
+    // Pass 1: open with a raw 'this' callback (no StabilizedCallback).
+    //
+    // On AAudio MMAP paths (Pixel 3+, Snapdragon 8 Gen 1+, most modern
+    // Android), the kernel delivers audio callbacks with near-perfect timing
+    // via the hardware FIFO interrupt.  StabilizedCallback works by sleeping
+    // on the callback thread to normalise jitter — on MMAP that sleep is pure
+    // overhead: it delays the write to the hardware ring buffer, adding latency
+    // without removing any real jitter.
+    //
+    // We probe by opening with the raw callback first.  If MMAP is confirmed
+    // we keep this stream.  If not, we close it and reopen with
+    // StabilizedCallback (see Pass 2 below) to cover the non-MMAP / OpenSL ES
+    // fallback path where OS scheduler jitter is real.
+    // -----------------------------------------------------------------------
+    stabilizedCallback_.reset();
+    auto rawCb = std::shared_ptr<oboe::AudioStreamDataCallback>(
+        std::shared_ptr<void>(), static_cast<oboe::AudioStreamDataCallback*>(this));
 
     oboe::AudioStreamBuilder builder;
     builder.setDirection(oboe::Direction::Output)
@@ -120,18 +139,50 @@ bool OboeBridge::open(int32_t sampleRate) {
            ->setIsContentSpatialized(true)
            // Prevent other apps from capturing our audio stream (competitive integrity).
            ->setAllowedCapturePolicy(oboe::AllowedCapturePolicy::None)
-           // Use shared_ptr overload (non-deprecated) for data callback.
-           ->setDataCallback(stabilizedCallback_)
-           // Non-owning shared_ptr for error callback — OboeBridge outlives the stream.
-           ->setErrorCallback(std::shared_ptr<oboe::AudioStreamErrorCallback>(
-               std::shared_ptr<void>(), static_cast<oboe::AudioStreamErrorCallback*>(this)));
+           ->setDataCallback(rawCb)
+           ->setErrorCallback(errorCb);
 
     oboe::Result result = builder.openStream(stream_);
 
-    if (result != oboe::Result::OK) {
+    if (result == oboe::Result::OK) {
+        bool mmapActive = oboe::OboeExtensions::isMMapUsed(stream_.get());
+        LOGI("Oboe pass-1 open: MMAP=%s", mmapActive ? "yes" : "no");
+
+        if (!mmapActive) {
+            // ---------------------------------------------------------------
+            // Pass 2: MMAP unavailable — close and reopen with StabilizedCallback.
+            // StabilizedCallback adds a compensating sleep to normalise the
+            // variable latency introduced by the OS scheduler on non-MMAP paths,
+            // reducing buffer underruns on devices that rely on AAudio binder IPC
+            // or the OpenSL ES compatibility layer.
+            // ---------------------------------------------------------------
+            stream_->close();
+            stream_.reset();
+
+            stabilizedCallback_ = std::make_shared<oboe::StabilizedCallback>(this);
+
+            builder.setDataCallback(stabilizedCallback_);
+            result = builder.openStream(stream_);
+
+            if (result != oboe::Result::OK) {
+                LOGE("AAudio + StabilizedCallback open failed (%s), falling back to unspecified API",
+                     oboe::convertToText(result));
+                { std::lock_guard<std::mutex> eLock(errorLock_); lastError_ = std::string("AAudio: ") + oboe::convertToText(result); }
+                builder.setAudioApi(oboe::AudioApi::Unspecified);
+                builder.setSharingMode(oboe::SharingMode::Shared);
+                result = builder.openStream(stream_);
+            }
+        }
+    } else {
+        // AAudio exclusive failed outright — try unspecified API + shared mode.
+        // Always wrap with StabilizedCallback on this fallback path since we
+        // almost certainly won't have MMAP on an OpenSL ES device.
         LOGE("AAudio open failed (%s), falling back to unspecified API",
              oboe::convertToText(result));
         { std::lock_guard<std::mutex> eLock(errorLock_); lastError_ = std::string("AAudio: ") + oboe::convertToText(result); }
+
+        stabilizedCallback_ = std::make_shared<oboe::StabilizedCallback>(this);
+        builder.setDataCallback(stabilizedCallback_);
         builder.setAudioApi(oboe::AudioApi::Unspecified);
         builder.setSharingMode(oboe::SharingMode::Shared);
         result = builder.openStream(stream_);
@@ -168,14 +219,15 @@ bool OboeBridge::open(int32_t sampleRate) {
     tuner_ = std::make_unique<oboe::LatencyTuner>(*stream_);
 
     LOGI("Oboe stream opened: api=%s, sampleRate=%d, framesPerBurst=%d, "
-         "bufferSize=%d, bufferCapacity=%d, sharingMode=%s, mmap=%s",
+         "bufferSize=%d, bufferCapacity=%d, sharingMode=%s, mmap=%s, stabilized=%s",
          stream_->getAudioApi() == oboe::AudioApi::AAudio ? "AAudio" : "OpenSLES",
          stream_->getSampleRate(),
          stream_->getFramesPerBurst(),
          stream_->getBufferSizeInFrames(),
          stream_->getBufferCapacityInFrames(),
          stream_->getSharingMode() == oboe::SharingMode::Exclusive ? "Exclusive" : "Shared",
-         oboe::OboeExtensions::isMMapUsed(stream_.get()) ? "yes" : "no");
+         oboe::OboeExtensions::isMMapUsed(stream_.get()) ? "yes" : "no",
+         stabilizedCallback_ ? "yes" : "no");
 
     return true;
 }
@@ -302,8 +354,10 @@ oboe::DataCallbackResult OboeBridge::onAudioReady(
         framesRead = std::clamp(framesRead, 0, numFrames);
 
         if (framesRead < numFrames) {
-            size_t bytesDone = static_cast<size_t>(framesRead) * stream->getChannelCount() * sizeof(float);
-            size_t totalBytes = static_cast<size_t>(numFrames) * stream->getChannelCount() * sizeof(float);
+            // Cache channel count in a local to avoid two virtual dispatches.
+            int32_t ch = stream->getChannelCount();
+            size_t bytesDone = static_cast<size_t>(framesRead) * ch * sizeof(float);
+            size_t totalBytes = static_cast<size_t>(numFrames) * ch * sizeof(float);
             memset(static_cast<char*>(audioData) + bytesDone, 0, totalBytes - bytesDone);
         }
     } else {

osu.Android/OsuGameAndroid.cs

@@ -27,6 +27,7 @@
 using osu.Framework.Platform;
 using osu.Game;
 using osu.Game.Configuration;
+using osu.Game.Database;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Settings;
 using osu.Game.Screens;
@@ -186,6 +187,9 @@ public partial class OsuGameAndroid : OsuGame
         private IntPtr adpfInputSession;
         private double inputAdpfAccumulatedMs;
         private long inputAdpfLastReportMs; // Environment.TickCount64 ms timestamp of last ADPF report
+        // Cached display-frame period in ms. Recomputed in applyDisplayMode so the hot
+        // input callback (which can fire at ~100 kHz) reads a plain field, not Math.Round.
+        private long adpfInputIntervalMs = 8L;
 
         // One-shot System.Threading.Timer that runs a burst of background-thread taming passes
         // when the user transitions into active gameplay.  Cancelled and replaced on each new
@@ -1488,6 +1492,8 @@ private void applyDisplayMode(global::Android.Views.Display display, global::And
                 try
                 {
                     currentRefreshRate = (int)mode.RefreshRate;
+                    // Cache the interval so the input hot-path avoids Math.Round on every poll.
+                    adpfInputIntervalMs = currentRefreshRate > 0 ? (long)Math.Round(1000.0 / currentRefreshRate) : 8L;
 
                     // Request the refresh rate via Surface.setFrameRate() ONLY.
                     //
@@ -1610,13 +1616,11 @@ private void onInputFrameCompleted()
 
                 inputAdpfAccumulatedMs += elapsedMs;
 
-                // Report once per display frame period.  `currentRefreshRate` is an int written
-                // from the UI thread — a torn or stale read is harmless (worst-case we use a
-                // slightly wrong interval for one report cycle).
-                long intervalMs = currentRefreshRate > 0 ? (long)Math.Round(1000.0 / currentRefreshRate) : 8L;
+                // Report once per display frame period.  `adpfInputIntervalMs` is pre-computed
+                // in applyDisplayMode() so this callback reads a plain field instead of calling Math.Round.
                 long nowMs = System.Environment.TickCount64;
 
-                if (nowMs - inputAdpfLastReportMs >= intervalMs)
+                if (nowMs - inputAdpfLastReportMs >= adpfInputIntervalMs)
                 {
                     OboeAudioBridge.nADPFReportActualDuration(adpfInputSession, (long)(inputAdpfAccumulatedMs * 1_000_000.0));
                     inputAdpfAccumulatedMs = 0;
@@ -2725,6 +2729,8 @@ private static bool isFrameworkDuplicateOfAndroidHandler(osu.Framework.Input.Han
 
         protected override UpdateManager CreateUpdateManager() => new MobileUpdateNotifier();
 
+        protected override BackgroundDataStoreProcessor CreateBackgroundDataStoreProcessor() => new AndroidBackgroundDataStoreProcessor();
+
         protected override BatteryInfo CreateBatteryInfo() => new AndroidBatteryInfo();
 
         protected override void Dispose(bool isDisposing)

osu.Game.Rulesets.Catch/UI/Catcher.cs

@@ -390,7 +390,7 @@ private Vector2 computePositionInStack(Vector2 position, float displayRadius)
             float adjustedRadius = displayRadius * lenience_adjust;
             float checkDistance = MathF.Pow(adjustedRadius, 2);
 
-            while (caughtObjectContainer.Any(f => Vector2Extensions.DistanceSquared(f.Position, position) < checkDistance))
+            while (tooCloseToExistingObject(position, checkDistance))
             {
                 position.X += RNG.NextSingle(-adjustedRadius, adjustedRadius);
                 position.Y -= RNG.NextSingle(0, 5);
@@ -399,6 +399,17 @@ private Vector2 computePositionInStack(Vector2 position, float displayRadius)
             return position;
         }
 
+        private bool tooCloseToExistingObject(Vector2 position, float checkDistance)
+        {
+            foreach (var f in caughtObjectContainer)
+            {
+                if (Vector2Extensions.DistanceSquared(f.Position, position) < checkDistance)
+                    return true;
+            }
+
+            return false;
+        }
+
         private void addLighting(JudgementResult judgementResult, Color4 colour, float x) =>
             hitExplosionContainer.Add(new HitExplosionEntry(Time.Current, judgementResult, colour, x));
 

osu.Game.Rulesets.Osu/Mods/OsuModBubbles.cs

@@ -111,7 +111,17 @@ public void ApplyToDrawableHitObject(DrawableHitObject drawableObject)
             {
                 if (drawable.HitObject is SpinnerTick or Slider) return;
 
-                BubbleDrawable? lastBubble = bubbleContainer.OfType<BubbleDrawable>().LastOrDefault();
+                // Reverse linear scan avoids the OfType<BubbleDrawable>().LastOrDefault() LINQ allocations.
+                BubbleDrawable? lastBubble = null;
+
+                for (int i = bubbleContainer.Children.Count - 1; i >= 0; i--)
+                {
+                    if (bubbleContainer.Children[i] is BubbleDrawable b)
+                    {
+                        lastBubble = b;
+                        break;
+                    }
+                }
 
                 lastBubble?.ClearTransforms();
                 lastBubble?.Expire(true);

osu.Game.Rulesets.Osu/Mods/OsuModRelax.cs

@@ -80,8 +80,12 @@ public void Update(Playfield playfield)
 
             double time = playfield.Clock.CurrentTime;
 
-            foreach (var h in playfield.HitObjectContainer.AliveObjects.OfType<DrawableOsuHitObject>())
+            foreach (DrawableHitObject dho in playfield.HitObjectContainer.AliveObjects)
             {
+                // All alive objects in an osu! playfield are DrawableOsuHitObjects.
+                // Casting inline avoids the OfType<> LINQ state-machine allocation per frame.
+                if (dho is not DrawableOsuHitObject h)
+                    continue;
                 // we are not yet close enough to the object.
                 if (time < h.HitObject.StartTime - RELAX_LENIENCY)
                     break;

osu.Game.Rulesets.Osu/Mods/OsuModStrictTracking.cs

@@ -46,9 +46,19 @@ public void ApplyToDrawableHitObject(DrawableHitObject drawable)
                     if (slider.Clock is IGameplayClock { IsRewinding: true })
                         return;
 
-                    var tail = slider.NestedHitObjects.OfType<StrictTrackingDrawableSliderTail>().First();
+                    // Manual scan avoids allocating a LINQ state-machine on every tracking-change event.
+                    StrictTrackingDrawableSliderTail? tail = null;
 
-                    if (!tail.Judged)
+                    foreach (var nested in slider.NestedHitObjects)
+                    {
+                        if (nested is StrictTrackingDrawableSliderTail t)
+                        {
+                            tail = t;
+                            break;
+                        }
+                    }
+
+                    if (tail != null && !tail.Judged)
                         tail.MissForcefully();
                 };
             }

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableHitCircle.cs

@@ -33,7 +33,8 @@ public partial class DrawableHitCircle : DrawableOsuHitObject, IHasApproachCircl
         public HitReceptor HitArea { get; private set; } = null!;
         public SkinnableDrawable CirclePiece { get; private set; } = null!;
 
-        protected override IEnumerable<Drawable> DimmablePieces => new[] { CirclePiece };
+        protected override IEnumerable<Drawable> DimmablePieces => dimmablePieces;
+        private Drawable[] dimmablePieces = null!;
 
         Drawable IHasApproachCircle.ApproachCircle => ApproachCircle;
 
@@ -96,6 +97,8 @@ private void load()
 
             Size = HitArea.DrawSize;
 
+            dimmablePieces = new Drawable[] { CirclePiece };
+
             PositionBindable.BindValueChanged(_ => UpdatePosition());
             StackHeightBindable.BindValueChanged(_ => UpdatePosition());
             ScaleBindable.BindValueChanged(scale => scaleContainer.Scale = new Vector2(scale.NewValue));

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableOsuHitObject.cs

@@ -108,8 +108,11 @@ protected override void ClearNestedHitObjects()
             // and because of separate pooling of parent and child objects, there is no guarantee that the pieces will be associated with `this` again on re-use.
             // therefore, clean up the subscription here to avoid crosstalk.
             // not doing so can result in the callback attempting to read things from `this` when it is in a completely bogus state (not in use or similar).
-            foreach (var piece in DimmablePieces.OfType<DrawableHitObject>())
-                piece.ApplyCustomUpdateState -= applyDimToDrawableHitObject;
+            foreach (var piece in DimmablePieces)
+            {
+                if (piece is DrawableHitObject dho)
+                    dho.ApplyCustomUpdateState -= applyDimToDrawableHitObject;
+            }
         }
 
         private void applyDim(Drawable piece)

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs

@@ -164,8 +164,10 @@ protected override void LoadSamples()
         {
             // Note: base.LoadSamples() isn't called since the slider plays the tail's hitsounds for the time being.
 
-            Samples.Samples = HitObject.TailSamples.Cast<ISampleInfo>().ToArray();
-            slidingSample.Samples = HitObject.CreateSlidingSamples().Cast<ISampleInfo>().ToArray();
+            // HitSampleInfo : ISampleInfo (reference type) — array covariance lets us cast directly,
+            // avoiding a second array allocation from .Cast<ISampleInfo>().ToArray().
+            Samples.Samples = (ISampleInfo[])HitObject.TailSamples.ToArray();
+            slidingSample.Samples = (ISampleInfo[])HitObject.CreateSlidingSamples().ToArray();
         }
 
         public override void StopAllSamples()
@@ -301,7 +303,10 @@ protected override void CheckForResult(bool userTriggered, double timeOffset)
                 ApplyResult(static (r, hitObject) =>
                 {
                     int totalTicks = hitObject.NestedHitObjects.Count;
-                    int hitTicks = hitObject.NestedHitObjects.Count(h => h.IsHit);
+                    int hitTicks = 0;
+
+                    foreach (var h in hitObject.NestedHitObjects)
+                        if (h.IsHit) hitTicks++;
 
                     if (hitTicks == totalTicks)
                         r.Type = HitResult.Great;
@@ -320,7 +325,18 @@ protected override void CheckForResult(bool userTriggered, double timeOffset)
                 // But the slider needs to still be judged with a reasonable hit/miss result for visual purposes (hit/miss transforms, etc).
                 ApplyResult(static (r, hitObject) =>
                 {
-                    r.Type = hitObject.NestedHitObjects.Any(h => h.Result.IsHit) ? r.Judgement.MaxResult : r.Judgement.MinResult;
+                    bool anyHit = false;
+
+                    foreach (var h in hitObject.NestedHitObjects)
+                    {
+                        if (h.Result.IsHit)
+                        {
+                            anyHit = true;
+                            break;
+                        }
+                    }
+
+                    r.Type = anyHit ? r.Judgement.MaxResult : r.Judgement.MinResult;
                 });
             }
         }