diff --git a/spacy/syntax/stateclass.pyx b/spacy/syntax/stateclass.pyx
index 65bb89c0b..d193c64c5 100644
--- a/spacy/syntax/stateclass.pyx
+++ b/spacy/syntax/stateclass.pyx
@@ -1,3 +1,4 @@
+# cython: profile=True
 from libc.string cimport memcpy, memset
 from libc.stdint cimport uint32_t
 from ..vocab cimport EMPTY_LEXEME