diff --git a/cmd/godoc/x.go b/cmd/godoc/x.go
index d6ee745f..13e600c7 100644
--- a/cmd/godoc/x.go
+++ b/cmd/godoc/x.go
@@ -35,6 +35,7 @@ var xMap = map[string]xRepo{
 	"mobile":     {"https://go.googlesource.com/mobile", "git"},
 	"net":        {"https://go.googlesource.com/net", "git"},
 	"oauth2":     {"https://go.googlesource.com/oauth2", "git"},
+	"perf":       {"https://go.googlesource.com/perf", "git"},
 	"playground": {"https://go.googlesource.com/playground", "git"},
 	"review":     {"https://go.googlesource.com/review", "git"},
 	"sync":       {"https://go.googlesource.com/sync", "git"},