1 files changed, 190 insertions, 0 deletions
diff --git a/src/runtime/append_test.go b/src/runtime/append_test.go
new file mode 100644
index 000000000..a67dc9b49
--- /dev/null
+++ b/src/runtime/append_test.go
@@ -0,0 +1,190 @@
+// 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 "testing"
+
+const N = 20
+
+func BenchmarkAppend(b *testing.B) {
+	b.StopTimer()
+	x := make([]int, 0, N)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		x = x[0:0]
+		for j := 0; j < N; j++ {
+			x = append(x, j)
+		}
+	}
+}
+
+func BenchmarkAppendGrowByte(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x []byte
+		for j := 0; j < 1<<20; j++ {
+			x = append(x, byte(j))
+		}
+	}
+}
+
+func BenchmarkAppendGrowString(b *testing.B) {
+	var s string
+	for i := 0; i < b.N; i++ {
+		var x []string
+		for j := 0; j < 1<<20; j++ {
+			x = append(x, s)
+		}
+	}
+}
+
+func benchmarkAppendBytes(b *testing.B, length int) {
+	b.StopTimer()
+	x := make([]byte, 0, N)
+	y := make([]byte, length)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		x = x[0:0]
+		x = append(x, y...)
+	}
+}
+
+func BenchmarkAppend1Byte(b *testing.B) {
+	benchmarkAppendBytes(b, 1)
+}
+
+func BenchmarkAppend4Bytes(b *testing.B) {
+	benchmarkAppendBytes(b, 4)
+}
+
+func BenchmarkAppend7Bytes(b *testing.B) {
+	benchmarkAppendBytes(b, 7)
+}
+
+func BenchmarkAppend8Bytes(b *testing.B) {
+	benchmarkAppendBytes(b, 8)
+}
+
+func BenchmarkAppend15Bytes(b *testing.B) {
+	benchmarkAppendBytes(b, 15)
+}
+
+func BenchmarkAppend16Bytes(b *testing.B) {
+	benchmarkAppendBytes(b, 16)
+}
+
+func BenchmarkAppend32Bytes(b *testing.B) {
+	benchmarkAppendBytes(b, 32)
+}
+
+func benchmarkAppendStr(b *testing.B, str string) {
+	b.StopTimer()
+	x := make([]byte, 0, N)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		x = x[0:0]
+		x = append(x, str...)
+	}
+}
+
+func BenchmarkAppendStr1Byte(b *testing.B) {
+	benchmarkAppendStr(b, "1")
+}
+
+func BenchmarkAppendStr4Bytes(b *testing.B) {
+	benchmarkAppendStr(b, "1234")
+}
+
+func BenchmarkAppendStr8Bytes(b *testing.B) {
+	benchmarkAppendStr(b, "12345678")
+}
+
+func BenchmarkAppendStr16Bytes(b *testing.B) {
+	benchmarkAppendStr(b, "1234567890123456")
+}
+
+func BenchmarkAppendStr32Bytes(b *testing.B) {
+	benchmarkAppendStr(b, "12345678901234567890123456789012")
+}
+
+func BenchmarkAppendSpecialCase(b *testing.B) {
+	b.StopTimer()
+	x := make([]int, 0, N)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		x = x[0:0]
+		for j := 0; j < N; j++ {
+			if len(x) < cap(x) {
+				x = x[:len(x)+1]
+				x[len(x)-1] = j
+			} else {
+				x = append(x, j)
+			}
+		}
+	}
+}
+
+var x []int
+
+func f() int {
+	x[:1][0] = 3
+	return 2
+}
+
+func TestSideEffectOrder(t *testing.T) {
+	x = make([]int, 0, 10)
+	x = append(x, 1, f())
+	if x[0] != 1 || x[1] != 2 {
+		t.Error("append failed: ", x[0], x[1])
+	}
+}
+
+func TestAppendOverlap(t *testing.T) {
+	x := []byte("1234")
+	x = append(x[1:], x...) // p > q in runtime·appendslice.
+	got := string(x)
+	want := "2341234"
+	if got != want {
+		t.Errorf("overlap failed: got %q want %q", got, want)
+	}
+}
+
+func benchmarkCopySlice(b *testing.B, l int) {
+	s := make([]byte, l)
+	buf := make([]byte, 4096)
+	var n int
+	for i := 0; i < b.N; i++ {
+		n = copy(buf, s)
+	}
+	b.SetBytes(int64(n))
+}
+
+func benchmarkCopyStr(b *testing.B, l int) {
+	s := string(make([]byte, l))
+	buf := make([]byte, 4096)
+	var n int
+	for i := 0; i < b.N; i++ {
+		n = copy(buf, s)
+	}
+	b.SetBytes(int64(n))
+}
+
+func BenchmarkCopy1Byte(b *testing.B)    { benchmarkCopySlice(b, 1) }
+func BenchmarkCopy2Byte(b *testing.B)    { benchmarkCopySlice(b, 2) }
+func BenchmarkCopy4Byte(b *testing.B)    { benchmarkCopySlice(b, 4) }
+func BenchmarkCopy8Byte(b *testing.B)    { benchmarkCopySlice(b, 8) }
+func BenchmarkCopy12Byte(b *testing.B)   { benchmarkCopySlice(b, 12) }
+func BenchmarkCopy16Byte(b *testing.B)   { benchmarkCopySlice(b, 16) }
+func BenchmarkCopy32Byte(b *testing.B)   { benchmarkCopySlice(b, 32) }
+func BenchmarkCopy128Byte(b *testing.B)  { benchmarkCopySlice(b, 128) }
+func BenchmarkCopy1024Byte(b *testing.B) { benchmarkCopySlice(b, 1024) }
+
+func BenchmarkCopy1String(b *testing.B)    { benchmarkCopyStr(b, 1) }
+func BenchmarkCopy2String(b *testing.B)    { benchmarkCopyStr(b, 2) }
+func BenchmarkCopy4String(b *testing.B)    { benchmarkCopyStr(b, 4) }
+func BenchmarkCopy8String(b *testing.B)    { benchmarkCopyStr(b, 8) }
+func BenchmarkCopy12String(b *testing.B)   { benchmarkCopyStr(b, 12) }
+func BenchmarkCopy16String(b *testing.B)   { benchmarkCopyStr(b, 16) }
+func BenchmarkCopy32String(b *testing.B)   { benchmarkCopyStr(b, 32) }
+func BenchmarkCopy128String(b *testing.B)  { benchmarkCopyStr(b, 128) }
+func BenchmarkCopy1024String(b *testing.B) { benchmarkCopyStr(b, 1024) }