diff --git a/python/dune/codegen/sumfact/autotune.py b/python/dune/codegen/sumfact/autotune.py
index 9f8dcdb10ad4ebbbb79be2d6c794e6e084555a22..e7a31f137869571f36e7f62febfa188f57a0fef4 100644
--- a/python/dune/codegen/sumfact/autotune.py
+++ b/python/dune/codegen/sumfact/autotune.py
@@ -210,7 +210,7 @@ def generate_standalone_code_google_benchmark(sf, filename):
         arguments = ', '.join(sf.interface.signature_args)
         if len(arguments) > 0:
             arguments = ', ' + arguments
-        arguments = 'const char* buffer0, const char* buffer 1' + arguments
+        arguments = 'const char* buffer0, const char* buffer1' + arguments
         f.write("void sumfact_kernel({})\n".format(arguments))
         for line in knl.member.lines[1:]:
             f.write("{}\n".format(line))