1 files changed, 41 insertions, 0 deletions
diff --git a/src/pkg/runtime/gc_test.go b/src/pkg/runtime/gc_test.go
new file mode 100644
index 000000000..65894a6fd
--- /dev/null
+++ b/src/pkg/runtime/gc_test.go
@@ -0,0 +1,41 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+	"runtime"
+	"testing"
+)
+
+func TestGcSys(t *testing.T) {
+	memstats := new(runtime.MemStats)
+	runtime.GC()
+	runtime.ReadMemStats(memstats)
+	sys := memstats.Sys
+
+	itercount := 1000000
+	if testing.Short() {
+		itercount = 100000
+	}
+	for i := 0; i < itercount; i++ {
+		workthegc()
+	}
+
+	// Should only be using a few MB.
+	runtime.ReadMemStats(memstats)
+	if sys > memstats.Sys {
+		sys = 0
+	} else {
+		sys = memstats.Sys - sys
+	}
+	t.Logf("used %d extra bytes", sys)
+	if sys > 4<<20 {
+		t.Fatalf("using too much memory: %d bytes", sys)
+	}
+}
+
+func workthegc() []byte {
+	return make([]byte, 1029)
+}