diff --git a/src/Makefile.am b/src/Makefile.am
index bf2f6404..ccb966ca 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -195,6 +195,7 @@ sptps_test_SOURCES += \
 endif
 
 tinc_LDADD = $(READLINE_LIBS) $(CURSES_LIBS)
+sptps_speed_LDADD = -lrt
 
 LIBS = @LIBS@ @LIBGCRYPT_LIBS@