[ET-VK] Changing texture access pattern for conv2d dw ops to improve …

…performance.

This diff changes the texture access pattern for convolutional depthwise (DW) operations in Executorch's Vulkan backend to iterate first on x axis then y and then z to improve performance.

Differential Revision: [D67770160](https://our.internmc.facebook.com/intern/diff/D67770160/)

[ghstack-poisoned]

backends/vulkan/runtime/graph/ops/glsl/conv2d_dw.glsl

@@ -35,7 +35,10 @@ layout(local_size_x_id = 0, local_size_y_id = 1, local_size_z_id = 2) in;
  * output at a single output location.
  */
 void main() {
-  const ivec3 pos = ivec3(gl_GlobalInvocationID);
+  const ivec3 pos = ivec3(
+    gl_GlobalInvocationID.x % out_limits.x,
+    (gl_GlobalInvocationID.x / out_limits.x) % out_limits.y,
+    gl_GlobalInvocationID.x / (out_limits.x * out_limits.y));
 
   if (any(greaterThanEqual(pos, out_limits))) {
     return;

backends/vulkan/runtime/graph/ops/glsl/conv2d_dw_output_tile.glsl

@@ -39,7 +39,10 @@ layout(local_size_x_id = 0, local_size_y_id = 1, local_size_z_id = 2) in;
  * output at a single output location.
  */
 void main() {
-  const u16vec3 pos = u16vec3(gl_GlobalInvocationID);
+  const u16vec3 pos = u16vec3(
+    gl_GlobalInvocationID.x % out_limits.x,
+    (gl_GlobalInvocationID.x / out_limits.x) % out_limits.y,
+    gl_GlobalInvocationID.x / (out_limits.x * out_limits.y));
 
   if (any(greaterThanEqual(pos, out_limits))) {
     return;

backends/vulkan/runtime/graph/ops/impl/Convolution.cpp

@@ -372,7 +372,7 @@ void add_conv2d_node(
 
   utils::uvec3 wg_size = create_conv2d_global_wg_size(graph, method, out);
 
-  if (method == Conv2dMethod::Pointwise) {
+  if (method == Conv2dMethod::Pointwise || method == Conv2dMethod::Depthwise) {
     wg_size = {wg_size[0] * wg_size[1] * wg_size[2], 1, 1};
   }