optimize embedding cuda kernel lookup_table_v2,test=develop (#25587)

paddle/fluid/operators/lookup_table_v2_op.cu

@@ -105,17 +105,17 @@ class LookupTableV2CUDAKernel : public framework::OpKernel<T> {
     auto *table = table_t->data<T>();
     auto *output = output_t->mutable_data<T>(context.GetPlace());
 
-    dim3 threads(128, 8);
-    dim3 grids(8, 1);
+    dim3 threads(256, 4);
+    dim3 grids(80, 1);
 
     if (padding_idx == -1)
       LookupTableV2<
-          T, 128, 8, 8,
+          T, 256, 4, 80,
           false><<<grids, threads, 0, context.cuda_device_context().stream()>>>(
           output, table, ids, N, K, D, padding_idx);
     else
       LookupTableV2<
-          T, 128, 8, 8,
+          T, 256, 4, 80,
           true><<<grids, threads, 0, context.cuda_device_context().stream()>>>(
           output, table, ids, N, K, D, padding_idx);
   }