diff --git a/README.adoc b/README.adoc
index 8e36d2d..97ec5de 100644
--- a/README.adoc
+++ b/README.adoc
@@ -3717,6 +3717,12 @@ This is consistent with the fact that ccache reduces the build time only partial
 
 The instructions counts varied very little between the baseline and LKMC, so runtime overhead is not a big deal apparently.
 
+==== P51 gem5
+
+How long it takes to build gem5 itself:
+
+* x86 at 68af229490fc811aebddf68b3e2e09e63a5fa475: 9m40s
+
 ==== T430
 
 Build time: 2 hours.