Merge pull request #10754 from dkurt:dnn_ocl_gemv_min_globalsize

modules/dnn/src/ocl4dnn/src/math_functions.cpp

@@ -451,6 +451,9 @@ bool ocl4dnnGEMV<float>(const CBLAS_TRANSPOSE TransA,
 
         uint row_size = M;
         uint col_size = N;
+
+        if (row_size >= 4)
+        {
             size_t localsize[] = { 128 };
             size_t globalsize[] = { row_size / 4 * localsize[0] };
 
@@ -468,6 +471,7 @@ bool ocl4dnnGEMV<float>(const CBLAS_TRANSPOSE TransA,
             k.set(argId++, NULL, localsize[0] * sizeof(cl_float4));
 
             ret = k.run(1, globalsize, localsize, false);
+        }
 
         if ((row_size % 4) != 0 && ret)
         {