diff --git a/dev/haring/README b/dev/haring/README
index 69d08a86c9..5205cf271e 100644
--- a/dev/haring/README
+++ b/dev/haring/README
@@ -2,3 +2,8 @@ This needs to be built from the top makefile, for example :
 
   make dev/haring/haring
 
+If HAProxy is built with special options such -DDEBUG_THREAD or with
+multi-threading support enabled (which changes the ring's header size),
+it can be worth reusing the same build options for haring, usually they
+will remain compatible, and will simplify the handling of different file
+layouts, at the expense of dragging more dependencies into the executable.