Bug 275422 – [WebGPU] IPC copies too much data leading to jetsams on iOS

• Status: RESOLVED
• Resolution: FIXED
• Component: WebGPU

[Mike Wyrzykowski]

[WebGPU] IPC copies too much data leading to jetsams on iOS

We can use SharedMemory to avoid this I think

[Radar WebKit Bug Importer]

<rdar://problem/129714560>

[Mike Wyrzykowski]

The following IPC messages are problematic:

Source/WebKit/GPUProcess/graphics/WebGPU//RemoteQueue.messages.in:    void WriteBuffer(WebKit::WebGPUIdentifier identifier, WebCore::WebGPU::Size64 bufferOffset, Vector<uint8_t> data)

Source/WebKit/GPUProcess/graphics/WebGPU//RemoteQueue.messages.in:    void WriteTexture(WebKit::WebGPU::ImageCopyTexture destination, Vector<uint8_t> data, WebKit::WebGPU::ImageDataLayout imageDataLayout, WebKit::WebGPU::Extent3D size)

Source/WebKit/GPUProcess/graphics/WebGPU//RemoteBuffer.messages.in:    void GetMappedRange(WebCore::WebGPU::Size64 offset, std::optional<WebCore::WebGPU::Size64> size) -> (std::optional<Vector<uint8_t>> data) Synchronous

Source/WebKit/GPUProcess/graphics/WebGPU//RemoteBuffer.messages.in:    void Copy(Vector<uint8_t> data, size_t offset)

[Mike Wyrzykowski]

It looks like Unity is also passing a large ArrayBuffer to writeTexture and writeBuffer, but we copy the entire ArrayBuffer passing over to IPC instead of only the bytes which will be needed by GPUQueue.writeTexture and GPUQueue.writeBuffer

[Mike Wyrzykowski]

Fixing this and https://boat-demo.cds.unity3d.com/ loads almost instantly now, comparable to Chrome

[Mike Wyrzykowski]

Pull request: https://github.com/WebKit/WebKit/pull/29809

[EWS]

Committed 280124@main (bdf8fc7b595b): <https://commits.webkit.org/280124@main>

Reviewed commits have been landed. Closing PR #29809 and removing active labels.