opencl: specify subgroup size instead of querying it

Author: lhez

ggml/src/ggml-opencl/ggml-opencl.cpp

@@ -3358,8 +3358,8 @@ static void ggml_cl_rms_norm(ggml_backend_t backend, const ggml_tensor * src0, c
     ggml_backend_opencl_context *backend_ctx = (ggml_backend_opencl_context *)backend->context;
     cl_command_queue queue = backend_ctx->queue;
 
-    ggml_backend_opencl_device_context * dev_ctx =
-        (ggml_backend_opencl_device_context *)backend->device->context;
+    //ggml_backend_opencl_device_context * dev_ctx =
+    //    (ggml_backend_opencl_device_context *)backend->device->context;
 
     ggml_tensor_extra_cl * extra0 = (ggml_tensor_extra_cl *)src0->extra;
     ggml_tensor_extra_cl * extrad = (ggml_tensor_extra_cl *)dst->extra;
@@ -3390,13 +3390,20 @@ static void ggml_cl_rms_norm(ggml_backend_t backend, const ggml_tensor * src0, c
 
     // Note, this kernel declares local memory in kernel args and the size
     // depends on subgroup size.
-    // Retrieve subgroup size.
     // Note, this requires OpenCL 2.1 and above
+    // For now we use fixed subgroup size to simplify support for OpenCL 2.0.
     size_t sgs;
-    CL_CHECK(clGetKernelSubGroupInfo(kernel, dev_ctx->device,
-        CL_KERNEL_MAX_SUB_GROUP_SIZE_FOR_NDRANGE,
-        sizeof(local_work_size), local_work_size,
-        sizeof(size_t), &sgs, NULL));
+    //CL_CHECK(clGetKernelSubGroupInfo(kernel, dev_ctx->device,
+    //    CL_KERNEL_MAX_SUB_GROUP_SIZE_FOR_NDRANGE,
+    //    sizeof(local_work_size), local_work_size,
+    //    sizeof(size_t), &sgs, NULL));
+    if (backend_ctx->gpu_family == ADRENO) {
+        sgs = 64;
+    } else if (backend_ctx->gpu_family == INTEL) {
+        sgs = 32;
+    } else {
+        GGML_ASSERT(false && "Unsupported GPU");
+    }
 
     CL_CHECK(clSetKernelArg(kernel,  0, sizeof(cl_mem),    &extra0->data_device));
     CL_CHECK(clSetKernelArg(kernel,  1, sizeof(cl_ulong),  &offset0));

ggml/src/ggml-opencl/kernels/rms_norm.cl

@@ -15,10 +15,31 @@
 #error "Selecting subgroup size is not supported on your device."
 #endif
 
+#ifdef cl_intel_required_subgroup_size
+// Always use subgroup size of 32 on Intel.
+#pragma OPENCL EXTENSION cl_intel_required_subgroup_size : enable
+#define INTEL_GPU 1
+#define REQD_SUBGROUP_SIZE_16 __attribute__((intel_reqd_sub_group_size(16)))
+#define REQD_SUBGROUP_SIZE_32 __attribute__((intel_reqd_sub_group_size(32)))
+#elif defined(cl_qcom_reqd_sub_group_size)
+// Always use subgroups size of 64 on Adreno.
+#pragma OPENCL EXTENSION cl_qcom_reqd_sub_group_size : enable
+#define ADRENO_GPU 1
+#define REQD_SUBGROUP_SIZE_64  __attribute__((qcom_reqd_sub_group_size("half")))
+#define REQD_SUBGROUP_SIZE_128 __attribute__((qcom_reqd_sub_group_size("full")))
+#else
+#error "Selecting subgroup size is not supported on your device."
+#endif
+
 //------------------------------------------------------------------------------
 // rms_norm
 //------------------------------------------------------------------------------
 // This kernel depends on subgroup size.
+#ifdef INTEL_GPU
+REQD_SUBGROUP_SIZE_32
+#elif defined (ADRENO_GPU)
+REQD_SUBGROUP_SIZE_64
+#endif
 kernel void kernel_rms_norm(
         global void * src0,
         ulong offset0,