diff --git a/modules/gtprof/trace_builtin.go b/modules/gtprof/trace_builtin.go
index 2590ed3a13..7b4e3b8b4f 100644
--- a/modules/gtprof/trace_builtin.go
+++ b/modules/gtprof/trace_builtin.go
@@ -40,7 +40,7 @@ func (t *traceBuiltinSpan) toString(out *strings.Builder, indent int) {
 	if t.ts.endTime.IsZero() {
 		out.WriteString(" duration: (not ended)")
 	} else {
-		fmt.Fprintf(out, " duration=%.4fs", t.ts.endTime.Sub(t.ts.startTime).Seconds())
+		fmt.Fprintf(out, " start=%s duration=%.4fs", t.ts.startTime.Format("2006-01-02 15:04:05"), t.ts.endTime.Sub(t.ts.startTime).Seconds())
 	}
 	for _, a := range t.ts.attributes {
 		out.WriteString(" ")