Skip to content

Move subgroup size handling in line with spec#8609

Merged
cwfitzgerald merged 1 commit intogfx-rs:trunkfrom
cwfitzgerald:cw/adapter-info
Dec 4, 2025
Merged

Move subgroup size handling in line with spec#8609
cwfitzgerald merged 1 commit intogfx-rs:trunkfrom
cwfitzgerald:cw/adapter-info

Conversation

@cwfitzgerald
Copy link
Member

Connections

Closes #8346

Description

Moved things over, as well as fix a few minor things in wgpu-info.

I have updated the defaults to the values specified by the WebGPU spec.

Testing

CI

Squash or Rebase?

Squash

@ErichDonGubler ErichDonGubler self-assigned this Dec 3, 2025
@cwfitzgerald cwfitzgerald changed the title Move subgroup size info to AdapterInfo Move subgroup size handling in line with spec Dec 3, 2025
///
/// See <https://gpuweb.github.io/gpuweb/#gpuadapterinfo>
/// where you can always use these values on all devices.
pub const MAXIMUM_SUBGROUP_MAX_SIZE: u32 = 128;
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Q: Is it possible to use more than this on some machines? If so, do we have any follow-up work for permitting larger groups?

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

No - the max observed subgroup size in the wild is 128 on qualcomm chips (and WARP). Similarly WARP supports the same range (4 to 128) so you can test with the full range of subgroups in the wild.

Copy link
Member

@ErichDonGubler ErichDonGubler left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM for merging. I have an open question, but I'm trusting this will get resolved either at or after merge.

Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
@cwfitzgerald cwfitzgerald enabled auto-merge (squash) December 4, 2025 16:44
@cwfitzgerald cwfitzgerald merged commit 9a41de4 into gfx-rs:trunk Dec 4, 2025
42 checks passed
github-merge-queue bot pushed a commit to bevyengine/bevy that referenced this pull request Jan 22, 2026
Upgrade to wgpu 28

> [!important]
> This can't merge until bevyengine/naga_oil#132
does, and the dependency is updated from my fork to the release.
> 
> Also requires wgpu 28 in dlss_wgpu:
bevyengine/dlss_wgpu#17

> [!note]
> This does not enable mesh shaders, and neither does the naga_oil PR. I
chose to do an upgrade first, then go back and see about mesh shaders.

Here's a general list of changes and what I did. Commits are grouped by
feature except for the last one, which enabled solari when I ran the
solari example.

## MipmapFilterMode is split from FilterMode

- Split MipmapFilterMode from FilterMode #8314:
gfx-rs/wgpu#8314

solution: implement From for `MipmapFilterMode`/`ImageFilterMode` since
the values are the same. The split was because the spec indicates they
are different types, even though they have the same values.

## Push Constants are now Immediates

- gfx-rs/wgpu#8724

immediate_size is [a
u32](https://docs.rs/wgpu/28.0.0/wgpu/struct.PipelineLayoutDescriptor.html#structfield.immediate_size)
so use that instead of `PushConstantRange`

## Capabilities name changes

- gfx-rs/wgpu#8671

Got new list from
https://github.com/gfx-rs/wgpu/blob/trunk/wgpu-core/src/device/mod.rs#L449
and copied it in.

## subgroup_{min,max}_size moved from Limits to AdapterInfo

- gfx-rs/wgpu#8609

Update the limits to have the fields they have now, mirror the logic
from the other limits calls.

## multiview_mask

- gfx-rs/wgpu#8206

set to None because we don't use it currently. Its vaguely for VR.

## error scope is now a guard

- gfx-rs/wgpu#8685

retain guard and then pop() it later


---

I made one mistake during the PR, thinking set_immediates was going to
be the size of the immediates and not the offset. I'd like reviewers to
take a look at immediates offset and size sites specifically just in
case I missed something.

Here's a bunch of examples running

<img width="1470" height="1040" alt="screenshot-2025-12-24-at-16 47
22@2x"
src="https://github.com/user-attachments/assets/83dcf4c8-69f5-480a-b724-86598530f25a"
/>
<img width="1470" height="1040" alt="screenshot-2025-12-24-at-16 48
44@2x"
src="https://github.com/user-attachments/assets/46d897fa-1ab2-44ef-8055-fe2fce740dbc"
/>
<img width="1470" height="1040" alt="screenshot-2025-12-24-at-16 49
10@2x"
src="https://github.com/user-attachments/assets/6ae7a9bf-0473-4800-8dfc-233a6a41d6df"
/>
<img width="1470" height="1040" alt="screenshot-2025-12-24-at-16 49
31@2x"
src="https://github.com/user-attachments/assets/89f84a26-cfbd-4196-bca8-111c3d20ba7b"
/>


## Known Issues

> [!NOTE]
> 
> There are no current known issues. Everything previous has been
solved.

- [x] enable extensions can not be written in naga oil in a way that
allows them to be used in composed modules.

Update: this was fixed by introducing a flag in naga-oil to force
shaders to allow ray queries in composed modules when using bevy_solari.
This is temporary and will be different in WESL-future.

<details><summary>old explanation</summary>
This is blocking solari from working on nvidia (solari runs successfully
on macos m1) because it needs `enable wgpu_ray_query;`. Putting the
declaration before `#define_import_path` means it gets stripped out
(afaict), and putting it after results in

```
error: expected global declaration, but found a global directive
  ┌─ embedded://bevy_solari/scene/raytracing_scene_bindings.wgsl:3:1
  │
3 │ enable wgpu_ray_query;
  │ ^^^^^^ written after first global declaration
  │
  = expected global declaration, but found a global directive
```

</details>

- [x] dlss_wgpu mixes apis which [causes panics
now](bevyengine/dlss_wgpu#17 (comment)).

<details><summary>Previous notes as dlss_wgpu was being fixed
here</summary>

The wgpu release notes don't mention which PR this was introduced in,
only saying:

> Using both the wgpu command encoding APIs and
CommandEncoder::as_hal_mut on the same encoder will now result in a
panic.

It was caused by gfx-rs/wgpu#8373 which claimed
to not know of any use cases

> With record on finish, the actual ordering on the command buffer is
deeply counter intuitive (all as_hal would come first) and I think it
additionally was just flat out broken in some ways
> -
https://discord.com/channels/691052431525675048/743663924229963868/1453786307099758683

Possible path forward is using multiple command buffers:
https://discord.com/channels/691052431525675048/743663924229963868/1453795633503670415

</summary>

---------

Co-authored-by: robtfm <50659922+robtfm@users.noreply.github.com>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

Min/max subgroup size should be adapter properties not limits

3 participants