diff --git a/src/runtime/malloc_test.go b/src/runtime/malloc_test.go
index 454b3c36fe..ecef9c93bc 100644
--- a/src/runtime/malloc_test.go
+++ b/src/runtime/malloc_test.go
@@ -44,6 +44,10 @@ func TestMemStats(t *testing.T) {
 	if st.HeapIdle+st.HeapInuse != st.HeapSys {
 		t.Fatalf("HeapIdle(%d) + HeapInuse(%d) should be equal to HeapSys(%d), but isn't.", st.HeapIdle, st.HeapInuse, st.HeapSys)
 	}
+
+	if lpe := st.PauseEnd[int(st.NumGC+255)%len(st.PauseEnd)]; st.LastGC != lpe {
+		t.Fatalf("LastGC(%d) != last PauseEnd(%d)", st.LastGC, lpe)
+	}
 }
 
 func TestStringConcatenationAllocs(t *testing.T) {
diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 5b6765b664..8375d30bb8 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -1436,9 +1436,10 @@ func gcMark(start_time int64) {
 	}
 
 	t4 := nanotime()
-	atomicstore64(&memstats.last_gc, uint64(unixnanotime())) // must be Unix time to make sense to user
+	unixNow := unixnanotime()
+	atomicstore64(&memstats.last_gc, uint64(unixNow)) // must be Unix time to make sense to user
 	memstats.pause_ns[memstats.numgc%uint32(len(memstats.pause_ns))] = uint64(t4 - t0)
-	memstats.pause_end[memstats.numgc%uint32(len(memstats.pause_end))] = uint64(t4)
+	memstats.pause_end[memstats.numgc%uint32(len(memstats.pause_end))] = uint64(unixNow)
 	memstats.pause_total_ns += uint64(t4 - t0)
 }