Cycles: Apple M3 tuning including hardware raytracing

This PR adds tunings for the [newly announced](https://www.youtube.com/watch?v=ctkW3V0Mh-k) M3 family of chips. In particular, MetalRT will be enabled as the automatic default for intersection testing on M3 and beyond to take advantage of hardware raytracing. This will result in significant path-tracing speedups, as well as faster BVH builds.

Pull Request: https://projects.blender.org/blender/blender/pulls/114296

intern/cycles/device/metal/device.mm

@@ -74,6 +74,9 @@ void device_metal_info(vector<DeviceInfo> &devices)
     }
 #  endif
 
+    /* Use hardware raytracing for faster rendering on architectures that support it. */
+    info.use_metalrt_by_default = (MetalInfo::get_apple_gpu_architecture(device) >= APPLE_M3);
+
     devices.push_back(info);
     device_index++;
   }

intern/cycles/device/metal/kernel.mm

@@ -41,6 +41,12 @@ struct ShaderCache {
     if (MetalInfo::get_device_vendor(mtlDevice) == METAL_GPU_APPLE) {
       switch (MetalInfo::get_apple_gpu_architecture(mtlDevice)) {
         default:
+        case APPLE_M3:
+          /* Peak occupancy is achieved through Dynamic Caching on M3 GPUs. */
+          for (size_t i = 0; i < DEVICE_KERNEL_NUM; i++) {
+            occupancy_tuning[i] = {64, 64};
+          }
+          break;
         case APPLE_M2_BIG:
           occupancy_tuning[DEVICE_KERNEL_INTEGRATOR_COMPACT_SHADOW_STATES] = {384, 128};
           occupancy_tuning[DEVICE_KERNEL_INTEGRATOR_INIT_FROM_CAMERA] = {640, 128};

intern/cycles/device/metal/util.h

@@ -31,6 +31,7 @@ enum AppleGPUArchitecture {
   APPLE_M1,
   APPLE_M2,
   APPLE_M2_BIG,
+  APPLE_M3,
 };
 
 /* Contains static Metal helper functions. */

intern/cycles/device/metal/util.mm

@@ -56,6 +56,9 @@ AppleGPUArchitecture MetalInfo::get_apple_gpu_architecture(id<MTLDevice> device)
   else if (strstr(device_name, "M2")) {
     return get_apple_gpu_core_count(device) <= 10 ? APPLE_M2 : APPLE_M2_BIG;
   }
+  else if (strstr(device_name, "M3")) {
+    return APPLE_M3;
+  }
   return APPLE_UNKNOWN;
 }