WebGPU f16 support

Category: Graphics
Type: Chromium catches up
Status: Enabled by default (Chrome 120)
Intent stage: None

Breaking change: No
Enterprise impact: None
Spec maturity: Published standard

WPT details: WebGPU/WGSL have a conformance test suite (https://github.com/gpuweb/cts) that is regularly pulled into Chromium and part of the testing of Dawn/Tint in Chromium. Test coverage for execution of f16 operations has been implemented, https://github.com/gpuweb/cts/issues/1248. Additional testing is in development.

Summary

Allows for the use of the half-precision floating-point type f16 in WebGPU shaders (WGSL). Developers can use the 'shader-f16' feature from the WebGPU spec and the 'f16' extension from the WGSL spec to access 16-bit floating point variables and APIs in their shaders.

Standards & signals

Specification: https://www.w3.org/TR/webgpu/#shader-f16
Firefox: Positive — Mozilla has already implemented this feature.
Safari: Positive
Web developers: Positive — f16 support in general has been requested feature in multiple different web runtimes/frameworks, e.g. https://github.com/microsoft/onnxruntime/issues/9758 and http://tc39.es/proposal-float16array/ From the initial proposal, https://github.com/gpuweb/gpuweb/issues/658, there were multiple benchmarks/demoes that indicate a substantial performance benefit shown in demos/tests, ~25% if ALU bound, and upto 50% if memory bound. TF.js has been investigating using f16 in WebGPU, https://github.com/gpuweb/gpuweb/issues/658#issuecomment-606492757 and already has it available in the WebGL implementation TF.js has significant improvements from forcing using Half Float (the GL equivalent feature), https://github.com/tensorflow/tfjs/issues/1047 The Dawn team has interacted with multiple internal and external partners that have indicated that f16 support is an important feature for them to get the performance needed to adopt WebGPU

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=webgpu%2FWGSL
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+WebGPU%20f16%20support
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=WebGPU%20f16%20support
Baseline status: https://webstatus.dev/?q=WebGPU%20f16%20support

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