diff --git a/pkg/stackparse/stackparse.go b/pkg/stackparse/stackparse.go
index 692ff5a..f66fefb 100644
--- a/pkg/stackparse/stackparse.go
+++ b/pkg/stackparse/stackparse.go
@@ -84,6 +84,7 @@ func Read(r io.Reader) ([]*StackSample, error) {
 	return samples, nil
 }
 
+// PkgDotName returns a package-qualified function name.
 func PkgDotName(f stack.Func) string {
 	return fmt.Sprintf("%s.%s", f.DirName, f.Name)
 }
diff --git a/pkg/stackparse/timeline.go b/pkg/stackparse/timeline.go
index 1989ad1..af817a0 100644
--- a/pkg/stackparse/timeline.go
+++ b/pkg/stackparse/timeline.go
@@ -240,6 +240,7 @@ func CreateTimeline(samples []*StackSample, ignoreCreators []string, goroutines
 	return tl
 }
 
+// InternalCall returns true if the call is internal to the Go runtime.
 func InternalCall(c stack.Call) bool {
 	if c.Func.DirName == "syscall" {
 		return true