GPUQueue: onSubmittedWorkDone() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is available in Web Workers.

The onSubmittedWorkDone() method of the GPUQueue interface returns a Promise that resolves when all the work submitted to the GPU via this GPUQueue at the point the method is called has been processed.

This includes the completion of any mapAsync() calls made on GPUBuffers used in commands submitted to the queue, before onSubmittedWorkDone() is called.

Note: In most cases, you do not need to call onSubmittedWorkDone(). You do not need to call it for mapping a buffer. mapAsync guarantees work submitted to the queue before calling mapAsync happens before the mapAsync returns (see WebGPU spec: section 5.2)

The two use cases for onSubmittedWorkDone

  1. Waiting for multiple buffer mapping (slow)

    js
    // good
    await Promise.all([
      buffer1.mapAsync(),
      buffer2.mapAsync(),
      buffer3.mapAsync(),
    ]);
    data1 = buffer1.getMappedRange();
    data2 = buffer2.getMappedRange();
    data3 = buffer3.getMappedRange();
    
    js
    // works but slow
    buffer1.mapAsync();
    buffer2.mapAsync();
    buffer3.mapAsync();
    await device.queue.onSubmittedWorkDone();
    data1 = buffer1.getMappedRange();
    data2 = buffer2.getMappedRange();
    data3 = buffer3.getMappedRange();
    

    The reason the second method is slow is, the implementation may be able to map the buffers before all the submitted work is done. For example, if all the buffers are finished being used, but more work (unrelated to the buffers) is already submitted, then you'll end up waiting longer using the second method than the first.

  2. Throttling work

    If you are doing heavy compute work and you submit too much work at once, the browser may kill your work. You can throttle the work by only submitting more work when the work you've already submitted is done.

Syntax

js
device.queue.onSubmittedWorkDone()

Parameters

None.

Return value

A Promise that resolves with Undefined.

Examples

js
device.queue.submit([commandEncoder.finish()]);
device.queue.onSubmittedWorkDone().then(() => {
  console.log("All submitted commands processed.");
});

Specifications

Specification
WebGPU
# dom-gpuqueue-onsubmittedworkdone

Browser compatibility

BCD tables only load in the browser

See also