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Add pixel diffing to RCTFrameTimingsObserver#56043

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Add pixel diffing to RCTFrameTimingsObserver#56043
huntie wants to merge 1 commit intofacebook:mainfrom
huntie:export-D95981881

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@huntie huntie commented Mar 10, 2026 •
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Summary:
Use pixel hash comparison to avoid encoding duplicate screenshots on iOS, reducing overhead when frames don't change.

  • Samples every 67th (prime denominator) 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

The end-to-end behaviour matches Android, but the pixel diffing approach is a unique accommodation for iOS.

  • Attempted CATransaction completion blocks, however these fire on commits that produce no visual change. No other public API on iOS.

Changelog: [Internal]

Differential Revision: D95981881

@meta-cla meta-cla bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Mar 10, 2026
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meta-codesync bot commented Mar 10, 2026

@huntie has exported this pull request. If you are a Meta employee, you can view the originating Diff in D95981881.

@huntie huntie force-pushed the export-D95981881 branch from 9644bd5 to 111447e Compare March 10, 2026 22:47
huntie added a commit to huntie/react-native that referenced this pull request Mar 10, 2026
@huntie @facebook-github-bot
Add pixel diffing to RCTFrameTimingsObserver (facebook#56043)
111447e 
Summary:

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]

Differential Revision: D95981881
@huntie @meta-codesync
Add pixel diffing to RCTFrameTimingsObserver (facebook#56043)
4f0961c 
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
@huntie huntie force-pushed the export-D95981881 branch from 111447e to 4f0961c Compare March 10, 2026 22:51
@meta-codesync meta-codesync bot closed this in 9d231af Mar 10, 2026
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react-native-bot commented Mar 10, 2026

This pull request was successfully merged by @huntie in 9d231af

When will my fix make it into a release? | How to file a pick request?

@react-native-bot react-native-bot added the Merged This PR has been merged. label Mar 10, 2026
@huntie huntie deleted the export-D95981881 branch March 10, 2026 23:36
huntie added a commit to huntie/react-native that referenced this pull request Mar 31, 2026
@huntie
Add pixel diffing to RCTFrameTimingsObserver (facebook#56043)
08be2fb 
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
huntie pushed a commit to huntie/react-native that referenced this pull request Apr 8, 2026
@hoxyq @huntie
Backport performance debugging improvements
55b30ce 
Backports some CDP Performance features and stability improvements to `0.83-stable`.

This includes:
- Remaining implementation of Frame Timings and screenshot capture in performance traces (Android)
- New support for Frame Timings and screenshot capture on iOS
- Optimisations to trace chunk generation, memory usage during performance recording
- `Page.captureScreenshot` (Android, iOS)

All features remain gated behind feature flags (`fuseboxFrameRecordingEnabled`, `fuseboxScreenshotCaptureEnabled`).

**Commits applied**

- Define TracingCategory enum (facebook#54377) bd6c6bf
- Use TracingCategory in TraceEvent (facebook#54378) ce60f27
- Simple parser for serialized tracing categories (facebook#54379) 62275b6
- Propagate tracing categories to recording state (facebook#54380) 3841ef0
- Re-land "Revert D85999774: [rn][android] Add FrameTiming module" (facebook#54502) 85905ad
- Add screenshot category (facebook#54537) 5d9cb80
- Define HostTargetTracingDelegate (facebook#54622) be0dae0
- Define TracingDelegate for Android Host (facebook#54628) a212e95
- Use new API for tracing state on Android (facebook#54629) 532d0be
- Internalize TracingState interface (facebook#54631) 58ec261
- Move TracingState interfaces to inspector package (facebook#54632) 10d0d99
- Rename values of TracingState enum (facebook#54630) be94707
- FrameTiming module to subscribe to Inspector tracing lifecycle (facebook#54633) 04ee02b
- Clarify HostTracingProfile and HostTraceRecordingState (facebook#54677) ec92f12
- Introduce TimeWindowedBuffer (facebook#54679) d6ee54f
- Keep tracing time window on TraceRecordingState (facebook#54673) e651563
- Define FrameTimingSequence (facebook#54674) 5b7d92f
- Define an endpoint on HostTarget to capture frame timings (facebook#54672) f469aa3
- Extract frame trace events construction logic (facebook#54675) 57973fa
- Define serializers for frame timings as part of HostTargetTracingProfile (facebook#54681) 587d360
- Propagate Frames data through Host (facebook#54671) 26ff069
- Cleanup no longer used jni layer for frame timings (facebook#54678) 9ba4ce6
- Fix screenshot typo (facebook#54742) 52186a3
- Add optional screenshot argument to FrameTimingSequence (facebook#54743) 57c29fc
- Frame screenshot event generation (facebook#54744) b447d26
- Frame screenshots capture implementation (facebook#54745) f3c9a8d
- BeginDrawing: INTENDED_VSYNC_TIMESTAMP -> VSYNC_TIMESTAMP (facebook#54765) 9221772
- Add frames category (facebook#54768) 31a0c9a
- Specify correct category for SetLayerTreeId event (facebook#54769) cd055e9
- Reduce the screenshots size (facebook#54800) e4a5a56
- Remove Commit from FrameTimingSequence (facebook#54779) 39f7703
- Fix potential bitmap leaks in FrameTimingsObserver (facebook#55652) 3918dd1
- Capture initial screenshot when starting frame timing trace (facebook#55720) 863f5c0
- Refactor FrameTimingsObserver for multi-activity support (facebook#55740) 8230f3b
- Reorder FrameTimingsObserver methods (facebook#55743) f56b295
- Increase frame capture quality, apply scaling after DPI normalization (facebook#55731) e5f9f5f
- Fix FrameTimingsObverver to initiate PixelCopy on main thread (facebook#55744) d552f2a
- Fix bitmap reuse race condition in FrameTimingsObserver (facebook#55745) 3924768
- Fix trailing frame capture after recording ended (facebook#55704) 47684ca
- Move base64Encode into react/utils (facebook#55873) 422770d
- Move screenshot Base64 encoding to trace serialization (facebook#55803) dc4c36e
- Restore inspector addPage listener callback (facebook#55925) 8c763fc
- Add tracing helper functions for RNDT traces in C++ and Kotlin (facebook#55935) 4f3f536
- Introduce fuseboxFrameRecordingEnabled flag, gate existing code (facebook#55941) 1aa7a32
- Implement Performance frames and screenshots on iOS (facebook#56015) 64a1a10
- Add pixel diffing to RCTFrameTimingsObserver (facebook#56043) 9d231af
- Add dynamic sampling to frame screenshots (facebook#56048) d309cda
- Switch trace event chunks from event count to size based (facebook#56080) d3b33f5
- Increase trace screenshot scale factor to 1x (facebook#56079) 972a30d
- Add Page.captureScreenshot CDP support (facebook#56307) 77332d2
- Fix data race on PerformanceObserver entry buffer (facebook#56352) 5eb1ca1
- [LOCAL] Remove stale frame event code from PerformanceTracer
- [LOCAL] Update Podfile.lock
@huntie huntie mentioned this pull request Apr 8, 2026
Draft
huntie pushed a commit to huntie/react-native that referenced this pull request Apr 8, 2026
@hoxyq @huntie
Backport performance debugging improvements
64f701d 
Backports some CDP Performance features and stability improvements to `0.83-stable`.

This includes:
- Remaining implementation of Frame Timings and screenshot capture in performance traces (Android)
- New support for Frame Timings and screenshot capture on iOS
- Optimisations to trace chunk generation, memory usage during performance recording
- `Page.captureScreenshot` (Android, iOS)

All features remain gated behind feature flags (`fuseboxFrameRecordingEnabled`, `fuseboxScreenshotCaptureEnabled`).

**Commits applied**

- Define TracingCategory enum (facebook#54377) bd6c6bf
- Use TracingCategory in TraceEvent (facebook#54378) ce60f27
- Simple parser for serialized tracing categories (facebook#54379) 62275b6
- Propagate tracing categories to recording state (facebook#54380) 3841ef0
- Re-land "Revert D85999774: [rn][android] Add FrameTiming module" (facebook#54502) 85905ad
- Add screenshot category (facebook#54537) 5d9cb80
- Define HostTargetTracingDelegate (facebook#54622) be0dae0
- Define TracingDelegate for Android Host (facebook#54628) a212e95
- Use new API for tracing state on Android (facebook#54629) 532d0be
- Internalize TracingState interface (facebook#54631) 58ec261
- Move TracingState interfaces to inspector package (facebook#54632) 10d0d99
- Rename values of TracingState enum (facebook#54630) be94707
- FrameTiming module to subscribe to Inspector tracing lifecycle (facebook#54633) 04ee02b
- Clarify HostTracingProfile and HostTraceRecordingState (facebook#54677) ec92f12
- Introduce TimeWindowedBuffer (facebook#54679) d6ee54f
- Keep tracing time window on TraceRecordingState (facebook#54673) e651563
- Define FrameTimingSequence (facebook#54674) 5b7d92f
- Define an endpoint on HostTarget to capture frame timings (facebook#54672) f469aa3
- Extract frame trace events construction logic (facebook#54675) 57973fa
- Define serializers for frame timings as part of HostTargetTracingProfile (facebook#54681) 587d360
- Propagate Frames data through Host (facebook#54671) 26ff069
- Cleanup no longer used jni layer for frame timings (facebook#54678) 9ba4ce6
- Fix screenshot typo (facebook#54742) 52186a3
- Add optional screenshot argument to FrameTimingSequence (facebook#54743) 57c29fc
- Frame screenshot event generation (facebook#54744) b447d26
- Frame screenshots capture implementation (facebook#54745) f3c9a8d
- BeginDrawing: INTENDED_VSYNC_TIMESTAMP -> VSYNC_TIMESTAMP (facebook#54765) 9221772
- Add frames category (facebook#54768) 31a0c9a
- Specify correct category for SetLayerTreeId event (facebook#54769) cd055e9
- Reduce the screenshots size (facebook#54800) e4a5a56
- Remove Commit from FrameTimingSequence (facebook#54779) 39f7703
- Fix potential bitmap leaks in FrameTimingsObserver (facebook#55652) 3918dd1
- Capture initial screenshot when starting frame timing trace (facebook#55720) 863f5c0
- Refactor FrameTimingsObserver for multi-activity support (facebook#55740) 8230f3b
- Reorder FrameTimingsObserver methods (facebook#55743) f56b295
- Increase frame capture quality, apply scaling after DPI normalization (facebook#55731) e5f9f5f
- Fix FrameTimingsObverver to initiate PixelCopy on main thread (facebook#55744) d552f2a
- Fix bitmap reuse race condition in FrameTimingsObserver (facebook#55745) 3924768
- Fix trailing frame capture after recording ended (facebook#55704) 47684ca
- Move base64Encode into react/utils (facebook#55873) 422770d
- Move screenshot Base64 encoding to trace serialization (facebook#55803) dc4c36e
- Restore inspector addPage listener callback (facebook#55925) 8c763fc
- Add tracing helper functions for RNDT traces in C++ and Kotlin (facebook#55935) 4f3f536
- Introduce fuseboxFrameRecordingEnabled flag, gate existing code (facebook#55941) 1aa7a32
- Implement Performance frames and screenshots on iOS (facebook#56015) 64a1a10
- Add pixel diffing to RCTFrameTimingsObserver (facebook#56043) 9d231af
- Add dynamic sampling to frame screenshots (facebook#56048) d309cda
- Switch trace event chunks from event count to size based (facebook#56080) d3b33f5
- Increase trace screenshot scale factor to 1x (facebook#56079) 972a30d
- Add Page.captureScreenshot CDP support (facebook#56307) 77332d2
- Fix data race on PerformanceObserver entry buffer (facebook#56352) 5eb1ca1
- [LOCAL] Remove stale frame event code from PerformanceTracer
- [LOCAL] Update Podfile.lock
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