diff --git a/setup.py b/setup.py
index a20eb58..fd0c002 100644
--- a/setup.py
+++ b/setup.py
@@ -97,6 +97,8 @@ def readme():
     test_suite="test",
     headers=glob("include/*.hxx"),
     ext_modules=[Extension("rank_filter",
+                            define_macros=[("CYTHON_TRACE", "1"),
+                                           ("CYTHON_TRACE_NOGIL", "1")],
                             sources=sources,
                             include_dirs=include_dirs,
                             library_dirs=library_dirs,