diff --git a/examples/benchmark.py b/examples/benchmark.py
index 3251a55ca3d0338edefd11c1d507f2d5b77272c0..0408fd28fc3917364eb208421f58ec8bec074835 100644
--- a/examples/benchmark.py
+++ b/examples/benchmark.py
@@ -54,6 +54,7 @@ for platform in cl.get_platforms():
         dest_buf = cl.Buffer(ctx, mf.WRITE_ONLY, b.nbytes)
 
         prg = cl.Program(ctx, """
+            #pragma OPENCL EXTENSION cl_khr_fp64 : enable
             __kernel void sum(__global const float *a,
             __global const float *b, __global float *c)
             {