diff --git a/test/eierpecken.c b/test/eierpecken.c
index a674bfe..f89926e 100644
--- a/test/eierpecken.c
+++ b/test/eierpecken.c
@@ -1056,3 +1056,10 @@ peck_eis_event_type_name(enum eis_event_type type)
 #undef CASE_STRING
 	assert(!"Unhandled EIS event type");
 }
+
+void
+_peck_mark(struct peck *peck, const char *func, int line)
+{
+	static uint32_t mark = 0;
+	log_debug(peck, "mark %3d: line %d in %s()\n", mark++, line, func);
+}
diff --git a/test/eierpecken.h b/test/eierpecken.h
index 9a4e439..949939f 100644
--- a/test/eierpecken.h
+++ b/test/eierpecken.h
@@ -134,6 +134,10 @@ struct peck;
 struct peck *
 peck_new(void);
 
+void _peck_mark(struct peck *peck, const char *func, int line);
+/** Add debug marker to the log output */
+#define peck_mark(peck_) _peck_mark(peck_, __func__, __LINE__)
+
 void
 peck_enable_eis_behavior(struct peck *peck, enum peck_eis_behavior behavior);