1// Copyright 2011 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4package runtime_test
5
6import "testing"
7
8const N = 20
9
10func BenchmarkAppend(b *testing.B) {
11	b.StopTimer()
12	x := make([]int, 0, N)
13	b.StartTimer()
14	for i := 0; i < b.N; i++ {
15		x = x[0:0]
16		for j := 0; j < N; j++ {
17			x = append(x, j)
18		}
19	}
20}
21
22func BenchmarkAppendGrowByte(b *testing.B) {
23	for i := 0; i < b.N; i++ {
24		var x []byte
25		for j := 0; j < 1<<20; j++ {
26			x = append(x, byte(j))
27		}
28	}
29}
30
31func BenchmarkAppendGrowString(b *testing.B) {
32	var s string
33	for i := 0; i < b.N; i++ {
34		var x []string
35		for j := 0; j < 1<<20; j++ {
36			x = append(x, s)
37		}
38	}
39}
40
41func benchmarkAppendBytes(b *testing.B, length int) {
42	b.StopTimer()
43	x := make([]byte, 0, N)
44	y := make([]byte, length)
45	b.StartTimer()
46	for i := 0; i < b.N; i++ {
47		x = x[0:0]
48		x = append(x, y...)
49	}
50}
51
52func BenchmarkAppend1Byte(b *testing.B) {
53	benchmarkAppendBytes(b, 1)
54}
55
56func BenchmarkAppend4Bytes(b *testing.B) {
57	benchmarkAppendBytes(b, 4)
58}
59
60func BenchmarkAppend7Bytes(b *testing.B) {
61	benchmarkAppendBytes(b, 7)
62}
63
64func BenchmarkAppend8Bytes(b *testing.B) {
65	benchmarkAppendBytes(b, 8)
66}
67
68func BenchmarkAppend15Bytes(b *testing.B) {
69	benchmarkAppendBytes(b, 15)
70}
71
72func BenchmarkAppend16Bytes(b *testing.B) {
73	benchmarkAppendBytes(b, 16)
74}
75
76func BenchmarkAppend32Bytes(b *testing.B) {
77	benchmarkAppendBytes(b, 32)
78}
79
80func benchmarkAppendStr(b *testing.B, str string) {
81	b.StopTimer()
82	x := make([]byte, 0, N)
83	b.StartTimer()
84	for i := 0; i < b.N; i++ {
85		x = x[0:0]
86		x = append(x, str...)
87	}
88}
89
90func BenchmarkAppendStr1Byte(b *testing.B) {
91	benchmarkAppendStr(b, "1")
92}
93
94func BenchmarkAppendStr4Bytes(b *testing.B) {
95	benchmarkAppendStr(b, "1234")
96}
97
98func BenchmarkAppendStr8Bytes(b *testing.B) {
99	benchmarkAppendStr(b, "12345678")
100}
101
102func BenchmarkAppendStr16Bytes(b *testing.B) {
103	benchmarkAppendStr(b, "1234567890123456")
104}
105
106func BenchmarkAppendStr32Bytes(b *testing.B) {
107	benchmarkAppendStr(b, "12345678901234567890123456789012")
108}
109
110func BenchmarkAppendSpecialCase(b *testing.B) {
111	b.StopTimer()
112	x := make([]int, 0, N)
113	b.StartTimer()
114	for i := 0; i < b.N; i++ {
115		x = x[0:0]
116		for j := 0; j < N; j++ {
117			if len(x) < cap(x) {
118				x = x[:len(x)+1]
119				x[len(x)-1] = j
120			} else {
121				x = append(x, j)
122			}
123		}
124	}
125}
126
127var x []int
128
129func f() int {
130	x[:1][0] = 3
131	return 2
132}
133
134func TestSideEffectOrder(t *testing.T) {
135	x = make([]int, 0, 10)
136	x = append(x, 1, f())
137	if x[0] != 1 || x[1] != 2 {
138		t.Error("append failed: ", x[0], x[1])
139	}
140}
141
142func TestAppendOverlap(t *testing.T) {
143	x := []byte("1234")
144	x = append(x[1:], x...) // p > q in runtime·appendslice.
145	got := string(x)
146	want := "2341234"
147	if got != want {
148		t.Errorf("overlap failed: got %q want %q", got, want)
149	}
150}
151
152func benchmarkCopySlice(b *testing.B, l int) {
153	s := make([]byte, l)
154	buf := make([]byte, 4096)
155	var n int
156	for i := 0; i < b.N; i++ {
157		n = copy(buf, s)
158	}
159	b.SetBytes(int64(n))
160}
161
162func benchmarkCopyStr(b *testing.B, l int) {
163	s := string(make([]byte, l))
164	buf := make([]byte, 4096)
165	var n int
166	for i := 0; i < b.N; i++ {
167		n = copy(buf, s)
168	}
169	b.SetBytes(int64(n))
170}
171
172func BenchmarkCopy1Byte(b *testing.B)    { benchmarkCopySlice(b, 1) }
173func BenchmarkCopy2Byte(b *testing.B)    { benchmarkCopySlice(b, 2) }
174func BenchmarkCopy4Byte(b *testing.B)    { benchmarkCopySlice(b, 4) }
175func BenchmarkCopy8Byte(b *testing.B)    { benchmarkCopySlice(b, 8) }
176func BenchmarkCopy12Byte(b *testing.B)   { benchmarkCopySlice(b, 12) }
177func BenchmarkCopy16Byte(b *testing.B)   { benchmarkCopySlice(b, 16) }
178func BenchmarkCopy32Byte(b *testing.B)   { benchmarkCopySlice(b, 32) }
179func BenchmarkCopy128Byte(b *testing.B)  { benchmarkCopySlice(b, 128) }
180func BenchmarkCopy1024Byte(b *testing.B) { benchmarkCopySlice(b, 1024) }
181
182func BenchmarkCopy1String(b *testing.B)    { benchmarkCopyStr(b, 1) }
183func BenchmarkCopy2String(b *testing.B)    { benchmarkCopyStr(b, 2) }
184func BenchmarkCopy4String(b *testing.B)    { benchmarkCopyStr(b, 4) }
185func BenchmarkCopy8String(b *testing.B)    { benchmarkCopyStr(b, 8) }
186func BenchmarkCopy12String(b *testing.B)   { benchmarkCopyStr(b, 12) }
187func BenchmarkCopy16String(b *testing.B)   { benchmarkCopyStr(b, 16) }
188func BenchmarkCopy32String(b *testing.B)   { benchmarkCopyStr(b, 32) }
189func BenchmarkCopy128String(b *testing.B)  { benchmarkCopyStr(b, 128) }
190func BenchmarkCopy1024String(b *testing.B) { benchmarkCopyStr(b, 1024) }
191