diff --git a/doc/README.log b/doc/README.log
index dc9e2de..2ee1b75 100644
--- a/doc/README.log
+++ b/doc/README.log
@@ -162,7 +162,8 @@
 ---------
 
 Code size impact depends largely on what is enabled. The following numbers are
-for snow, which is a Thumb-2 board:
+generated by 'buildman -S' for snow, which is a Thumb-2 board (all units in
+bytes):
 
 This series: adds bss +20.0 data +4.0 rodata +4.0 text +44.0
 CONFIG_LOG: bss -52.0 data +92.0 rodata -635.0 text +1048.0