diff --git a/ui/metrics/metrics.go b/ui/metrics/metrics.go
index ce2d946..717530c 100644
--- a/ui/metrics/metrics.go
+++ b/ui/metrics/metrics.go
@@ -32,13 +32,13 @@
 // of what an event is and how the metrics system is a stack based system.
 
 import (
+	"fmt"
 	"os"
 	"runtime"
 	"strings"
 	"time"
 
 	"android/soong/shared"
-
 	"google.golang.org/protobuf/proto"
 
 	soong_metrics_proto "android/soong/ui/metrics/metrics_proto"
@@ -223,6 +223,17 @@
 	m.metrics.BuildDateTimestamp = proto.Int64(buildTimestamp.UnixNano() / int64(time.Second))
 }
 
+func (m *Metrics) UpdateTotalRealTime(data []byte) error {
+	if err := proto.Unmarshal(data, &m.metrics); err != nil {
+		return fmt.Errorf("Failed to unmarshal proto", err)
+	}
+	startTime := *m.metrics.Total.StartTime
+	endTime := uint64(time.Now().UnixNano())
+
+	*m.metrics.Total.RealTime = *proto.Uint64(endTime - startTime)
+	return nil
+}
+
 // SetBuildCommand adds the build command specified by the user to the
 // list of collected metrics.
 func (m *Metrics) SetBuildCommand(cmd []string) {