Intent to Ship: WebGPU: Subgroup Size Control

[Chromestatus]

Contact emails

jiawe...@intel.com

Explainer

No information provided

Specification

https://github.com/gpuweb/gpuweb/pull/5578

Summary

Adds the optional GPU feature "subgroup-size-control" that allows explicitly setting the subgroup size in a compute shader. This technique is particularly useful for the applications that need to optimize the performance of the compute shader using subgroup operations with specifc subgroup size on certain platforms, such as the AI workloads.

Blink component

Blink>WebGPU

Web Feature ID

Missing feature

Motivation

Adds the optional GPU feature "subgroup-size-control" that allows explicitly setting the subgroup size in a compute shader. This technique is particularly useful for the applications that need to optimize the performance of the compute shader using subgroup operations with specifc subgroup size on certain platforms, such as the AI workloads.

Initial public proposal

No information provided

TAG review

No information provided

TAG review status

Pending

Goals for experimentation

None

Risks

Interoperability and Compatibility

This feature has been approved in W3C GPU for the Web WG meetings including participants from Safari and Firefox: https://github.com/gpuweb/gpuweb/wiki/GPU-Web-2026%E2%80%9006%E2%80%9023-WGSL#add-extension-subgroup-size-control-5578

Gecko: Positive (https://github.com/gpuweb/gpuweb/pull/5578) "Feedback indicated via WebGPU standardization process."

WebKit: Positive (https://github.com/gpuweb/gpuweb/pull/5578) "Specification approval constitutes a positive signal, per https://github.com/WebKit/standards-positions/issues/294#issuecomment-1877411933"

Web developers: No signals

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

No information provided

Debuggability

No information provided

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

No
Will immediately be available on Android, Android WebView, ChromeOS, Linux and Windows, where hardware support is available.

Is this feature fully tested by web-platform-tests?

Yes
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. While the CTS can be embedded in WPT, the WebGPU team opted to keep it separate in Chromium testing to use a customized harness for robustness and performance: https://github.com/gpuweb/cts/issues/4640

Flag name on about://flags

No information provided

Finch feature name

No information provided

Non-finch justification

No information provided

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/463721943

Estimated milestones

No milestones specified

Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).

No information provided

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5077657663438848?gate=6732991276646400

This intent message was generated by Chrome Platform Status.