diff --git a/test/heapsampling.go b/test/heapsampling.go
index ed9208c1f42..c00b866680a 100644
--- a/test/heapsampling.go
+++ b/test/heapsampling.go
@@ -92,6 +92,9 @@ func checkValue(fname string, ln int, name string, want, got int64) {
 
 func getMemProfileRecords() []runtime.MemProfileRecord {
 	// Force the runtime to update the object and byte counts.
+	// This can take up to two GC cycles to get a complete
+	// snapshot of the current point in time.
+	runtime.GC()
 	runtime.GC()
 
 	// Find out how many records there are (MemProfile(nil, true)),