Adds min_subgroup_size and max_subgroup_size device limits.

wgpu-hal/src/dx12/adapter.rs

@@ -389,6 +389,8 @@ impl super::Adapter {
                         .min(crate::MAX_VERTEX_BUFFERS as u32),
                     max_vertex_attributes: d3d12_ty::D3D12_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT,
                     max_vertex_buffer_array_stride: d3d12_ty::D3D12_SO_BUFFER_MAX_STRIDE_IN_BYTES,
+                    min_subgroup_size: 4, // Not using `features1.WaveLaneCountMin` as it is unreliable
+                    max_subgroup_size: 128,
                     // The push constants are part of the root signature which
                     // has a limit of 64 DWORDS (256 bytes), but other resources
                     // also share the root signature:

wgpu-hal/src/gles/adapter.rs

@@ -728,6 +728,8 @@ impl super::Adapter {
             } else {
                 !0
             },
+            min_subgroup_size: 0,
+            max_subgroup_size: 0,
             max_push_constant_size: super::MAX_PUSH_CONSTANTS as u32 * 4,
             min_uniform_buffer_offset_alignment,
             min_storage_buffer_offset_alignment,

wgpu-hal/src/metal/adapter.rs

@@ -960,6 +960,8 @@ impl super::PrivateCapabilities {
                 max_vertex_buffers: self.max_vertex_buffers,
                 max_vertex_attributes: 31,
                 max_vertex_buffer_array_stride: base.max_vertex_buffer_array_stride,
+                min_subgroup_size: 4,
+                max_subgroup_size: 64,
                 max_push_constant_size: 0x1000,
                 min_uniform_buffer_offset_alignment: self.buffer_alignment as u32,
                 min_storage_buffer_offset_alignment: self.buffer_alignment as u32,

wgpu-hal/src/vulkan/adapter.rs

@@ -1044,6 +1044,14 @@ impl PhysicalDeviceProperties {
                 .min(crate::MAX_VERTEX_BUFFERS as u32),
             max_vertex_attributes: limits.max_vertex_input_attributes,
             max_vertex_buffer_array_stride: limits.max_vertex_input_binding_stride,
+            min_subgroup_size: self
+                .subgroup_size_control
+                .map(|subgroup_size| subgroup_size.min_subgroup_size)
+                .unwrap_or(0),
+            max_subgroup_size: self
+                .subgroup_size_control
+                .map(|subgroup_size| subgroup_size.max_subgroup_size)
+                .unwrap_or(0),
             max_push_constant_size: limits.max_push_constants_size,
             min_uniform_buffer_offset_alignment: limits.min_uniform_buffer_offset_alignment as u32,
             min_storage_buffer_offset_alignment: limits.min_storage_buffer_offset_alignment as u32,

wgpu-info/src/human.rs

@@ -143,6 +143,8 @@ fn print_adapter(output: &mut impl io::Write, report: &AdapterReport, idx: usize
         max_vertex_buffers,
         max_vertex_attributes,
         max_vertex_buffer_array_stride,
+        min_subgroup_size,
+        max_subgroup_size,
         max_push_constant_size,
         min_uniform_buffer_offset_alignment,
         min_storage_buffer_offset_alignment,
@@ -176,6 +178,8 @@ fn print_adapter(output: &mut impl io::Write, report: &AdapterReport, idx: usize
     writeln!(output, "\t\t                              Max Vertex Buffers: {max_vertex_buffers}")?;
     writeln!(output, "\t\t                           Max Vertex Attributes: {max_vertex_attributes}")?;
     writeln!(output, "\t\t                  Max Vertex Buffer Array Stride: {max_vertex_buffer_array_stride}")?;
+    writeln!(output, "\t\t                               Min Subgroup Size: {min_subgroup_size}")?;
+    writeln!(output, "\t\t                               Max Subgroup Size: {max_subgroup_size}")?;
     writeln!(output, "\t\t                          Max Push Constant Size: {max_push_constant_size}")?;
     writeln!(output, "\t\t             Min Uniform Buffer Offset Alignment: {min_uniform_buffer_offset_alignment}")?;
     writeln!(output, "\t\t             Min Storage Buffer Offset Alignment: {min_storage_buffer_offset_alignment}")?;

wgpu-types/src/lib.rs

@@ -1160,6 +1160,11 @@ pub struct Limits {
     /// The maximum value for each dimension of a `ComputePass::dispatch(x, y, z)` operation.
     /// Defaults to 65535. Higher is "better".
     pub max_compute_workgroups_per_dimension: u32,
+
+    /// Minimal number of invocations in a subgroup. Higher is "better".
+    pub min_subgroup_size: u32,
+    /// Maximal number of invocations in a subgroup. Lower is "better".
+    pub max_subgroup_size: u32,
     /// Amount of storage available for push constants in bytes. Defaults to 0. Higher is "better".
     /// Requesting more than 0 during device creation requires [`Features::PUSH_CONSTANTS`] to be enabled.
     ///
@@ -1170,7 +1175,6 @@ pub struct Limits {
     /// - OpenGL doesn't natively support push constants, and are emulated with uniforms,
     ///   so this number is less useful but likely 256.
     pub max_push_constant_size: u32,
-
     /// Maximum number of live non-sampler bindings.
     ///
     /// This limit only affects the d3d12 backend. Using a large number will allow the device
@@ -1211,6 +1215,8 @@ impl Default for Limits {
             max_compute_workgroup_size_y: 256,
             max_compute_workgroup_size_z: 64,
             max_compute_workgroups_per_dimension: 65535,
+            min_subgroup_size: 0,
+            max_subgroup_size: 0,
             max_push_constant_size: 0,
             max_non_sampler_bindings: 1_000_000,
         }
@@ -1242,6 +1248,8 @@ impl Limits {
     ///     max_vertex_buffers: 8,
     ///     max_vertex_attributes: 16,
     ///     max_vertex_buffer_array_stride: 2048,
+    ///     min_subgroup_size: 0,
+    ///     max_subgroup_size: 0,
     ///     max_push_constant_size: 0,
     ///     min_uniform_buffer_offset_alignment: 256,
     ///     min_storage_buffer_offset_alignment: 256,
@@ -1278,6 +1286,8 @@ impl Limits {
             max_vertex_buffers: 8,
             max_vertex_attributes: 16,
             max_vertex_buffer_array_stride: 2048,
+            min_subgroup_size: 0,
+            max_subgroup_size: 0,
             max_push_constant_size: 0,
             min_uniform_buffer_offset_alignment: 256,
             min_storage_buffer_offset_alignment: 256,
@@ -1320,6 +1330,8 @@ impl Limits {
     ///     max_vertex_buffers: 8,
     ///     max_vertex_attributes: 16,
     ///     max_vertex_buffer_array_stride: 255, // +
+    ///     min_subgroup_size: 0,
+    ///     max_subgroup_size: 0,
     ///     max_push_constant_size: 0,
     ///     min_uniform_buffer_offset_alignment: 256,
     ///     min_storage_buffer_offset_alignment: 256,
@@ -1350,6 +1362,8 @@ impl Limits {
             max_compute_workgroup_size_y: 0,
             max_compute_workgroup_size_z: 0,
             max_compute_workgroups_per_dimension: 0,
+            min_subgroup_size: 0,
+            max_subgroup_size: 0,
 
             // Value supported by Intel Celeron B830 on Windows (OpenGL 3.1)
             max_inter_stage_shader_components: 31,
@@ -1442,6 +1456,10 @@ impl Limits {
         compare!(max_vertex_buffers, Less);
         compare!(max_vertex_attributes, Less);
         compare!(max_vertex_buffer_array_stride, Less);
+        if self.min_subgroup_size > 0 && self.max_subgroup_size > 0 {
+            compare!(min_subgroup_size, Greater);
+            compare!(max_subgroup_size, Less);
+        }
         compare!(max_push_constant_size, Less);
         compare!(min_uniform_buffer_offset_alignment, Greater);
         compare!(min_storage_buffer_offset_alignment, Greater);

wgpu/src/backend/webgpu.rs

@@ -737,6 +737,8 @@ fn map_wgt_limits(limits: webgpu_sys::GpuSupportedLimits) -> wgt::Limits {
         max_compute_workgroup_size_z: limits.max_compute_workgroup_size_z(),
         max_compute_workgroups_per_dimension: limits.max_compute_workgroups_per_dimension(),
         // The following are not part of WebGPU
+        min_subgroup_size: wgt::Limits::default().min_subgroup_size,
+        max_subgroup_size: wgt::Limits::default().max_subgroup_size,
         max_push_constant_size: wgt::Limits::default().max_push_constant_size,
         max_non_sampler_bindings: wgt::Limits::default().max_non_sampler_bindings,
     }