diff --git a/cmd/callgraph/main.go b/cmd/callgraph/main.go
index 2aa9739a41..29179dd877 100644
--- a/cmd/callgraph/main.go
+++ b/cmd/callgraph/main.go
@@ -42,7 +42,7 @@ import (
 )
 
 var algoFlag = flag.String("algo", "rta",
-	`Call graph construction algorithm, one of "rta" or "pta"`)
+	`Call graph construction algorithm (static, cha, rta, pta)`)
 
 var testFlag = flag.Bool("test", false,
 	"Loads test code (*_test.go) for imported packages")
diff --git a/go/callgraph/static/static.go b/go/callgraph/static/static.go
index ebb183bdc4..709bb7b6bd 100644
--- a/go/callgraph/static/static.go
+++ b/go/callgraph/static/static.go
@@ -15,6 +15,8 @@ func CallGraph(prog *ssa.Program) *callgraph.Graph {
 	cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph
 
 	// TODO(adonovan): opt: use only a single pass over the ssa.Program.
+	// TODO(adonovan): opt: this is slower than RTA (perhaps because
+	// the lower precision means so many edges are allocated)!
 	for f := range ssautil.AllFunctions(prog) {
 		fnode := cg.CreateNode(f)
 		for _, b := range f.Blocks {