[0.85] Backport performance debugging improvements#56637
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motiz88 wants to merge 14 commits intofacebook:0.85-stablefrom
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[0.85] Backport performance debugging improvements#56637motiz88 wants to merge 14 commits intofacebook:0.85-stablefrom
motiz88 wants to merge 14 commits intofacebook:0.85-stablefrom
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Summary: Pull Request resolved: facebook#55873 Move `base64Encode` implementation (originally vendored in D58323859) into `ReactCommon/react/utils/` for reuse in other C++ packages. Changelog: [Internal] Reviewed By: cipolleschi Differential Revision: D95041544 fbshipit-source-id: d71376d03079a8cc4d0a6c3652c40d73374858ea
Summary: Pull Request resolved: facebook#55803 Refactor Android FrameTimings to reduce memory usage in trace buffer. Binary data instead of Base64 should be ~25% smaller, and eliminates string copies during JNI transfer. Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D94657907 fbshipit-source-id: c4a183ff00c519fd1545992340fd445530abab99
…ook#55935) Summary: Pull Request resolved: facebook#55935 Changelog: [internal] This diff adds helper functions to the PerformanceTracer class for tracing performance events in React Native Developer Tools traces. In Kotlin, new `trace` method overloads are added to `PerformanceTracer` that wrap a block of code and automatically measure and report its execution time. These use a try/finally pattern to ensure timing is captured correctly. In C++, a new `PerformanceTracerSection` RAII class is added that automatically reports timing when the section goes out of scope. It supports optional track, track group, and color parameters, as well as variadic key-value properties for additional metadata. Reviewed By: sammy-SC Differential Revision: D92061513 fbshipit-source-id: 92c745426c6a9e3a2eee1e85e2a2d7fd12d88ef6
…book#55941) Summary: Pull Request resolved: facebook#55941 Replaces the previous `globalThis.enableTimelineFrames` setup with backend gating. Enables us to: - Iterate more safely by gating Android/iOS/C++ code - Have a per-app rollout at Meta Changelog: [Internal] Reviewed By: vzaidman Differential Revision: D95405444 fbshipit-source-id: 0c41f10059b28ed940a12a44707946baa310bdfb
Summary: Pull Request resolved: facebook#56015 Implements CDP support for the Chrome DevTools Frames track on iOS during a performance trace, including screenshot capture. This initial version matches the corresponding implementation for Android: - Captures the key window. - Always emits an initial frame. - Resizes screenshots at 0.75 scale factor (normalized for device screen DPI) and 80% JPEG compression. - Uses a background thread queue for image resizing. **To dos** - [ ] Emit frames only when there is a visual update. - [ ] Dynamic frame sampling on slower devices (planned for Android). **Limitations** - Not a true screen recording, uses `UIGraphicsImageRenderer`. - Requires no permission prompt ✅ - This can mean empty data (a black screen) is sent during states such as system alert dialogs being presented. - Like Android, if the background queue builds (on slower hardware), screenshot data can be lost when the recording is ended. This feature is gated behind the `fuseboxFrameRecordingEnabled` flag. Changelog: [Internal] Reviewed By: sbuggay Differential Revision: D95566220 fbshipit-source-id: c87f1b6d8334b45e2eb67334a5f0f924d20901ec
Summary: Pull Request resolved: facebook#56043 Use pixel hash comparison to avoid encoding duplicate screenshots on iOS, reducing overhead when frames don't change. Matches Android behaviour. - Samples every 64th pixel with a fast FNV-1a hash (~0.1ms on main thread). - Skips JPEG encoding and CDP transport entirely for unchanged frames — the dominant per-frame cost. **Why this approach** Attempted `CATransaction` completion blocks, however these fire on commits that produce no visual change. No other public API on iOS. Changelog: [Internal] Reviewed By: sbuggay Differential Revision: D95981881 fbshipit-source-id: 76f492f0ceb6b3efea3fce822036ed6cb6067b83
Summary: Pull Request resolved: facebook#56048 Update Android frame screenshot processing to skip screenshot capture when encoding is already in progress — now limited to a single background thread — while always emitting frame timing events. **Motivation** 1. Prevents truncated trace data on slower devices (e.g. missing screenshots for the last 1/3 of the trace), with the tradeoff of some intermediate frame screenshot loss. 2. Reduces total recording overhead by freeing up device threads - prevents excessive encoding work from blocking or slowing down the UI and other app threads. **Algorithm** Uses `encodingInProgress` atomic flag with single encoding thread and `lastFrameBuffer` storage for tail-capture of the last frame before idling (to capture settled animation states): - **Not encoding:** Frame passes directly to encoder → emits with screenshot when done - **Encoding busy:** Frame stored in `lastFrameBuffer` for tail-capture → any replaced frame emits without screenshot - **Encoding done:** Clears flag early, then opportunistically encodes tail frame without blocking new frames - **Failed captures:** Emit without screenshot immediately Result: Every frame emitted exactly once. Encoding adapts to device speed. Settled animation state guaranteed captured. **Remaining work** -⚠️ This still does not yet solve crashes (OkHttp network chunk size overflow) for heavy frame data at a high FPS on fast devices (coming next). Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D95987488 fbshipit-source-id: cda5758e3091edd227d3838638ba157dbcea52d8
) Summary: Pull Request resolved: facebook#56080 Trace event chunks were previously split by a fixed event count (1000). This caused issues with Frame Timing events containing screenshot data, where a single chunk could produce CDP messages of tens or hundreds of MBs — exceeding the OkHttp WebSocket limit (app crash). Address this problem by replacing count-based chunking with size-based chunking (max 10 MiB per chunk) for `emitFrameTimings()` and `emitPerformanceTraceEvents()`. A new `TraceEventSerializer::estimateJsonSize()` utility recursively estimates the serialized byte size of a `folly::dynamic` value to avoid double-serialization overhead. **Notes** - RuntimeSamplingProfile chunks (separate code path) remain count-based (inherently small, no screenshot data). Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D96206962 fbshipit-source-id: 6b6e4db76441f174c46bf34905292585d0e30899
Summary: Pull Request resolved: facebook#56079 Stacked on the current set of improvements, now further increase screenshot quality on Android. Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D96382172 fbshipit-source-id: 1f850d249142a7438eb0064194fac16ce6c9ae89
Summary: Pull Request resolved: facebook#56307 Implement the `Page.captureScreenshot` CDP command in the inspector backend, allowing DevTools to capture an on-demand screenshot of the current app view. This is a minimal implementation supporting only the `format` (jpeg/png/webp) and `quality` (0-100, jpeg only) parameters, returning base64-encoded image data. The feature is gated behind a new `fuseboxCaptureScreenshotEnabled` React Native feature flag, wired through `InspectorFlags` following the same pattern as frame recording. **Motivation** Improve agent verification / user feedback during AI sessions. We've proven that screenshots (in performance traces) are useful for understanding how components render on screen, and exposing this as an on-demand CDP method is relatively cheap today vs the larger task of modelling the DOM (Elements panel). **Changes** - New `fuseboxCaptureScreenshotEnabled` feature flag + `InspectorFlags` wiring (C++, Android JNI, Kotlin) - `HostTargetDelegate::captureScreenshot()` virtual method with async callback - C++ CDP handler in `HostAgent` — parses `format`/`quality`, delegates to platform, sends async CDP response (gated by flag) - iOS (`RCTHost.mm`): Captures key window via `UIGraphicsImageRenderer` + `drawViewHierarchyInRect`, encodes to PNG/JPEG - Android (`ReactHostImpl.kt`): Captures decor view via `Bitmap` + `Canvas` + `View.draw()`, encodes to PNG/JPEG/WebP - 4 C++ tests: success, failure, param forwarding, flag-disabled rejection Changelog: [Internal] Reviewed By: hoxyq Differential Revision: D99099930 fbshipit-source-id: d4d2ef86ba20d2ee230903e152dd21e11f29cbb8
Summary: Pull Request resolved: facebook#56352 Add mutex to protect `PerformanceObserver::buffer_` and `didScheduleFlushBuffer_`, which can be accessed concurrently from a background thread (`handleEntry`) and JS thread (`takeRecords`). Fixes T263429319. Changelog: [Internal] Reviewed By: jorge-cab Differential Revision: D99820359 fbshipit-source-id: 068fa1871b3a0feeb84b950b0c8f5fe7dcf38b7d
Summary: Pull Request resolved: facebook#56135 Ports the dynamic sampling algorithm from Android (D95987488) to iOS. Uses an `encodingInProgress` atomic flag with a single encoding thread and `lastFrameData` buffer to skip screenshot encoding when the encoder is busy, while always emitting frame timing events. This prevents truncated trace data on slower devices and reduces recording overhead. Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D97131485 fbshipit-source-id: 5c30f1052d5b5a61f27f2ab90946ef47b8b6b279
Summary: Pull Request resolved: facebook#56136 Following D97131485, brings iOS screenshot recording to parity with Android. NOTE: Dynamic frame sampling (D97131485) becomes more load bearing after this change, as a 1x scale increases processing overhead significantly. Let's continue dogfooding. Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D97131484 fbshipit-source-id: 4c03842ae22b905a50f989ff68fece7acc289a67
Summary: Pull Request resolved: facebook#56397 The `React-RuntimeApple` pod/target was missing the `REACT_NATIVE_DEBUGGER_ENABLED` preprocessor define in both open source build configurations. Without this, the experimental-and-flagged `fuseboxFrameRecordingEnabled` feature (D95566220) was misbehaving on iOS — code paths in `RCTHost.mm` were unexpectedly compiled out. See facebook#56372. Changelog: [Internal] Reviewed By: rubennorte Differential Revision: D100157250 fbshipit-source-id: 8c11287f34ac6029dd1153a01fed6ba93cc7d398
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Summary
Cherry-pick of 14 commits from
mainbringing Performance debugging features to0.85-stable. These commits landed onmainafter the 0.85 branch point and were previously backported to0.83-stableas a squashed commit in #56372.Changes included
base64Encodeintoreact/utils(Move base64Encode into react/utils #55873)fuseboxFrameRecordingEnabledflag, gate existing code (Introduce fuseboxFrameRecordingEnabled flag, gate existing code #55941)RCTFrameTimingsObserver(Add pixel diffing to RCTFrameTimingsObserver #56043)Page.captureScreenshotCDP support (Add Page.captureScreenshot CDP support (#56307) #56307)PerformanceObserverentry buffer (Fix data race on PerformanceObserver entry buffer #56352)All new features are gated behind
fuseboxFrameRecordingEnabledandfuseboxScreenshotCaptureEnabledfeature flags (both disabled by default).Two commits required regeneration of feature flag files (
yarn featureflags --update) due to the new flags; all other commits applied cleanly.Changelog:
[Internal]
Test Plan
cc @huntie