WebGPU backend not found in webworkers

[batman4444]

System information

• Have I written custom code (as opposed to using a stock example script provided in TensorFlow.js): Yes
• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Windows 11
• Mobile device (e.g. iPhone 8, Pixel 2, Samsung Galaxy) if the issue happens on mobile device: N/A
• TensorFlow.js installed from (npm or script link): Script Links
• TensorFlow.js version (use command below): 4.10.0
• Browser version: Chrome 116.0.5845.97
• Tensorflow.js Converter Version: N/A

Describe the current behavior
Using the following script links, when attempting to load the webGPU backend on a web worker (SharedWorker) I get a "Error: Backend name 'webgpu' not found in registry" error.

If I try loading the same script tags on main thread (not a webworker) it works as expected. Also, the "wasm" and "webgl" backends seems to work as expected.

Describe the expected behavior

SharedWorker should load 'webgpu' backend just like main thread

Standalone code to reproduce the issue

await import("https://cdn.jsdelivr.net/npm/@tensorflow/tfjs@4.10.0/dist/tf.min.js")
await import("https://cdn.jsdelivr.net/npm/@tensorflow/tfjs-backend-webgpu/dist/tf-backend-webgpu.js");
await tf.setBackend("webgpu");

Other info / logs
Uncaught (in promise) Error: Backend name 'webgpu' not found in registry
at e. (engine.js:276:13)
at h (tf.min.js:17:2100)
at Generator. (tf.min.js:17:3441)
at Generator.next (tf.min.js:17:2463)
at u (tf.min.js:17:8324)
at o (tf.min.js:17:8527)
at tf.min.js:17:8586
at new Promise ()
at e. (tf.min.js:17:8467)
at e. (engine.js:293:4)

[qjia7]

@hujiajie Please help to look at this issue. Thanks.

[hujiajie]

The WebGPU spec says "a GPU object is available in the Window and DedicatedWorkerGlobalScope contexts ...", but not in the SharedWorkerGlobalScope, so I don't think the WebGPU backend could work in shared workers at the moment.

https://gpuweb.github.io/gpuweb/#navigator-gpu

[gyagp]

WebGPU Working Group has an issue (gpuweb/gpuweb#4197) to track this.

[batman4444]

Thanks for the responses. As gyagp pointed out, it looks like there is already an open feature request to address this.

[libofei2004]

@gyagp @hujiajie Is there no way to use webgpu backend in webworker in webview in android?

[gyagp]

WebGPU Android hasn't been released. I didn't follow up the status closely, but you may take a look at this issue: https://bugs.chromium.org/p/dawn/issues/detail?id=286

[libofei2004]

@gyagp Thank you