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// Copyright 2013 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 (
"crypto/rand"
"encoding/binary"
"fmt"
"internal/race"
"internal/testenv"
. "runtime"
"sync/atomic"
"testing"
"unsafe"
)
func TestMemmove(t *testing.T) {
if *flagQuick {
t.Skip("-quick")
}
t.Parallel()
size := 256
if testing.Short() {
size = 128 + 16
}
src := make([]byte, size)
dst := make([]byte, size)
for i := 0; i < size; i++ {
src[i] = byte(128 + (i & 127))
}
for i := 0; i < size; i++ {
dst[i] = byte(i & 127)
}
for n := 0; n <= size; n++ {
for x := 0; x <= size-n; x++ { // offset in src
for y := 0; y <= size-n; y++ { // offset in dst
copy(dst[y:y+n], src[x:x+n])
for i := 0; i < y; i++ {
if dst[i] != byte(i&127) {
t.Fatalf("prefix dst[%d] = %d", i, dst[i])
}
}
for i := y; i < y+n; i++ {
if dst[i] != byte(128+((i-y+x)&127)) {
t.Fatalf("copied dst[%d] = %d", i, dst[i])
}
dst[i] = byte(i & 127) // reset dst
}
for i := y + n; i < size; i++ {
if dst[i] != byte(i&127) {
t.Fatalf("suffix dst[%d] = %d", i, dst[i])
}
}
}
}
}
}
func TestMemmoveAlias(t *testing.T) {
if *flagQuick {
t.Skip("-quick")
}
t.Parallel()
size := 256
if testing.Short() {
size = 128 + 16
}
buf := make([]byte, size)
for i := 0; i < size; i++ {
buf[i] = byte(i)
}
for n := 0; n <= size; n++ {
for x := 0; x <= size-n; x++ { // src offset
for y := 0; y <= size-n; y++ { // dst offset
copy(buf[y:y+n], buf[x:x+n])
for i := 0; i < y; i++ {
if buf[i] != byte(i) {
t.Fatalf("prefix buf[%d] = %d", i, buf[i])
}
}
for i := y; i < y+n; i++ {
if buf[i] != byte(i-y+x) {
t.Fatalf("copied buf[%d] = %d", i, buf[i])
}
buf[i] = byte(i) // reset buf
}
for i := y + n; i < size; i++ {
if buf[i] != byte(i) {
t.Fatalf("suffix buf[%d] = %d", i, buf[i])
}
}
}
}
}
}
func TestMemmoveLarge0x180000(t *testing.T) {
if testing.Short() && testenv.Builder() == "" {
t.Skip("-short")
}
t.Parallel()
if race.Enabled {
t.Skip("skipping large memmove test under race detector")
}
testSize(t, 0x180000)
}
func TestMemmoveOverlapLarge0x120000(t *testing.T) {
if testing.Short() && testenv.Builder() == "" {
t.Skip("-short")
}
t.Parallel()
if race.Enabled {
t.Skip("skipping large memmove test under race detector")
}
testOverlap(t, 0x120000)
}
func testSize(t *testing.T, size int) {
src := make([]byte, size)
dst := make([]byte, size)
_, _ = rand.Read(src)
_, _ = rand.Read(dst)
ref := make([]byte, size)
copyref(ref, dst)
for n := size - 50; n > 1; n >>= 1 {
for x := 0; x <= size-n; x = x*7 + 1 { // offset in src
for y := 0; y <= size-n; y = y*9 + 1 { // offset in dst
copy(dst[y:y+n], src[x:x+n])
copyref(ref[y:y+n], src[x:x+n])
p := cmpb(dst, ref)
if p >= 0 {
t.Fatalf("Copy failed, copying from src[%d:%d] to dst[%d:%d].\nOffset %d is different, %v != %v", x, x+n, y, y+n, p, dst[p], ref[p])
}
}
}
}
}
func testOverlap(t *testing.T, size int) {
src := make([]byte, size)
test := make([]byte, size)
ref := make([]byte, size)
_, _ = rand.Read(src)
for n := size - 50; n > 1; n >>= 1 {
for x := 0; x <= size-n; x = x*7 + 1 { // offset in src
for y := 0; y <= size-n; y = y*9 + 1 { // offset in dst
// Reset input
copyref(test, src)
copyref(ref, src)
copy(test[y:y+n], test[x:x+n])
if y <= x {
copyref(ref[y:y+n], ref[x:x+n])
} else {
copybw(ref[y:y+n], ref[x:x+n])
}
p := cmpb(test, ref)
if p >= 0 {
t.Fatalf("Copy failed, copying from src[%d:%d] to dst[%d:%d].\nOffset %d is different, %v != %v", x, x+n, y, y+n, p, test[p], ref[p])
}
}
}
}
}
// Forward copy.
func copyref(dst, src []byte) {
for i, v := range src {
dst[i] = v
}
}
// Backwards copy
func copybw(dst, src []byte) {
if len(src) == 0 {
return
}
for i := len(src) - 1; i >= 0; i-- {
dst[i] = src[i]
}
}
// Returns offset of difference
func matchLen(a, b []byte, max int) int {
a = a[:max]
b = b[:max]
for i, av := range a {
if b[i] != av {
return i
}
}
return max
}
func cmpb(a, b []byte) int {
l := matchLen(a, b, len(a))
if l == len(a) {
return -1
}
return l
}
// Ensure that memmove writes pointers atomically, so the GC won't
// observe a partially updated pointer.
func TestMemmoveAtomicity(t *testing.T) {
if race.Enabled {
t.Skip("skip under the race detector -- this test is intentionally racy")
}
var x int
for _, backward := range []bool{true, false} {
for _, n := range []int{3, 4, 5, 6, 7, 8, 9, 10, 15, 25, 49} {
n := n
// test copying [N]*int.
sz := uintptr(n * PtrSize)
name := fmt.Sprint(sz)
if backward {
name += "-backward"
} else {
name += "-forward"
}
t.Run(name, func(t *testing.T) {
// Use overlapping src and dst to force forward/backward copy.
var s [100]*int
src := s[n-1 : 2*n-1]
dst := s[:n]
if backward {
src, dst = dst, src
}
for i := range src {
src[i] = &x
}
for i := range dst {
dst[i] = nil
}
var ready atomic.Uint32
go func() {
sp := unsafe.Pointer(&src[0])
dp := unsafe.Pointer(&dst[0])
ready.Store(1)
for i := 0; i < 10000; i++ {
Memmove(dp, sp, sz)
MemclrNoHeapPointers(dp, sz)
}
ready.Store(2)
}()
for ready.Load() == 0 {
Gosched()
}
for ready.Load() != 2 {
for i := range dst {
p := dst[i]
if p != nil && p != &x {
t.Fatalf("got partially updated pointer %p at dst[%d], want either nil or %p", p, i, &x)
}
}
}
})
}
}
}
func benchmarkSizes(b *testing.B, sizes []int, fn func(b *testing.B, n int)) {
for _, n := range sizes {
b.Run(fmt.Sprint(n), func(b *testing.B) {
b.SetBytes(int64(n))
fn(b, n)
})
}
}
var bufSizes = []int{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
32, 64, 128, 256, 512, 1024, 2048, 4096,
}
var bufSizesOverlap = []int{
32, 64, 128, 256, 512, 1024, 2048, 4096,
}
func BenchmarkMemmove(b *testing.B) {
benchmarkSizes(b, bufSizes, func(b *testing.B, n int) {
x := make([]byte, n)
y := make([]byte, n)
for i := 0; i < b.N; i++ {
copy(x, y)
}
})
}
func BenchmarkMemmoveOverlap(b *testing.B) {
benchmarkSizes(b, bufSizesOverlap, func(b *testing.B, n int) {
x := make([]byte, n+16)
for i := 0; i < b.N; i++ {
copy(x[16:n+16], x[:n])
}
})
}
func BenchmarkMemmoveUnalignedDst(b *testing.B) {
benchmarkSizes(b, bufSizes, func(b *testing.B, n int) {
x := make([]byte, n+1)
y := make([]byte, n)
for i := 0; i < b.N; i++ {
copy(x[1:], y)
}
})
}
func BenchmarkMemmoveUnalignedDstOverlap(b *testing.B) {
benchmarkSizes(b, bufSizesOverlap, func(b *testing.B, n int) {
x := make([]byte, n+16)
for i := 0; i < b.N; i++ {
copy(x[16:n+16], x[1:n+1])
}
})
}
func BenchmarkMemmoveUnalignedSrc(b *testing.B) {
benchmarkSizes(b, bufSizes, func(b *testing.B, n int) {
x := make([]byte, n)
y := make([]byte, n+1)
for i := 0; i < b.N; i++ {
copy(x, y[1:])
}
})
}
func BenchmarkMemmoveUnalignedSrcOverlap(b *testing.B) {
benchmarkSizes(b, bufSizesOverlap, func(b *testing.B, n int) {
x := make([]byte, n+1)
for i := 0; i < b.N; i++ {
copy(x[1:n+1], x[:n])
}
})
}
func TestMemclr(t *testing.T) {
size := 512
if testing.Short() {
size = 128 + 16
}
mem := make([]byte, size)
for i := 0; i < size; i++ {
mem[i] = 0xee
}
for n := 0; n < size; n++ {
for x := 0; x <= size-n; x++ { // offset in mem
MemclrBytes(mem[x : x+n])
for i := 0; i < x; i++ {
if mem[i] != 0xee {
t.Fatalf("overwrite prefix mem[%d] = %d", i, mem[i])
}
}
for i := x; i < x+n; i++ {
if mem[i] != 0 {
t.Fatalf("failed clear mem[%d] = %d", i, mem[i])
}
mem[i] = 0xee
}
for i := x + n; i < size; i++ {
if mem[i] != 0xee {
t.Fatalf("overwrite suffix mem[%d] = %d", i, mem[i])
}
}
}
}
}
func BenchmarkMemclr(b *testing.B) {
for _, n := range []int{5, 16, 64, 256, 4096, 65536} {
x := make([]byte, n)
b.Run(fmt.Sprint(n), func(b *testing.B) {
b.SetBytes(int64(n))
for i := 0; i < b.N; i++ {
MemclrBytes(x)
}
})
}
for _, m := range []int{1, 4, 8, 16, 64} {
x := make([]byte, m<<20)
b.Run(fmt.Sprint(m, "M"), func(b *testing.B) {
b.SetBytes(int64(m << 20))
for i := 0; i < b.N; i++ {
MemclrBytes(x)
}
})
}
}
func BenchmarkGoMemclr(b *testing.B) {
benchmarkSizes(b, []int{5, 16, 64, 256}, func(b *testing.B, n int) {
x := make([]byte, n)
for i := 0; i < b.N; i++ {
for j := range x {
x[j] = 0
}
}
})
}
func BenchmarkMemclrRange(b *testing.B) {
type RunData struct {
data []int
}
benchSizes := []RunData{
{[]int{1043, 1078, 1894, 1582, 1044, 1165, 1467, 1100, 1919, 1562, 1932, 1645,
1412, 1038, 1576, 1200, 1029, 1336, 1095, 1494, 1350, 1025, 1502, 1548, 1316, 1296,
1868, 1639, 1546, 1626, 1642, 1308, 1726, 1665, 1678, 1187, 1515, 1598, 1353, 1237,
1977, 1452, 2012, 1914, 1514, 1136, 1975, 1618, 1536, 1695, 1600, 1733, 1392, 1099,
1358, 1996, 1224, 1783, 1197, 1838, 1460, 1556, 1554, 2020}}, // 1kb-2kb
{[]int{3964, 5139, 6573, 7775, 6553, 2413, 3466, 5394, 2469, 7336, 7091, 6745,
4028, 5643, 6164, 3475, 4138, 6908, 7559, 3335, 5660, 4122, 3945, 2082, 7564, 6584,
5111, 2288, 6789, 2797, 4928, 7986, 5163, 5447, 2999, 4968, 3174, 3202, 7908, 8137,
4735, 6161, 4646, 7592, 3083, 5329, 3687, 2754, 3599, 7231, 6455, 2549, 8063, 2189,
7121, 5048, 4277, 6626, 6306, 2815, 7473, 3963, 7549, 7255}}, // 2kb-8kb
{[]int{16304, 15936, 15760, 4736, 9136, 11184, 10160, 5952, 14560, 15744,
6624, 5872, 13088, 14656, 14192, 10304, 4112, 10384, 9344, 4496, 11392, 7024,
5200, 10064, 14784, 5808, 13504, 10480, 8512, 4896, 13264, 5600}}, // 4kb-16kb
{[]int{164576, 233136, 220224, 183280, 214112, 217248, 228560, 201728}}, // 128kb-256kb
}
for _, t := range benchSizes {
total := 0
minLen := 0
maxLen := 0
for _, clrLen := range t.data {
if clrLen > maxLen {
maxLen = clrLen
}
if clrLen < minLen || minLen == 0 {
minLen = clrLen
}
total += clrLen
}
buffer := make([]byte, maxLen)
text := ""
if minLen >= (1 << 20) {
text = fmt.Sprint(minLen>>20, "M ", (maxLen+(1<<20-1))>>20, "M")
} else if minLen >= (1 << 10) {
text = fmt.Sprint(minLen>>10, "K ", (maxLen+(1<<10-1))>>10, "K")
} else {
text = fmt.Sprint(minLen, " ", maxLen)
}
b.Run(text, func(b *testing.B) {
b.SetBytes(int64(total))
for i := 0; i < b.N; i++ {
for _, clrLen := range t.data {
MemclrBytes(buffer[:clrLen])
}
}
})
}
}
func BenchmarkClearFat7(b *testing.B) {
p := new([7]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [7]byte{}
}
}
func BenchmarkClearFat8(b *testing.B) {
p := new([8 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [8 / 4]uint32{}
}
}
func BenchmarkClearFat11(b *testing.B) {
p := new([11]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [11]byte{}
}
}
func BenchmarkClearFat12(b *testing.B) {
p := new([12 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [12 / 4]uint32{}
}
}
func BenchmarkClearFat13(b *testing.B) {
p := new([13]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [13]byte{}
}
}
func BenchmarkClearFat14(b *testing.B) {
p := new([14]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [14]byte{}
}
}
func BenchmarkClearFat15(b *testing.B) {
p := new([15]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [15]byte{}
}
}
func BenchmarkClearFat16(b *testing.B) {
p := new([16 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [16 / 4]uint32{}
}
}
func BenchmarkClearFat24(b *testing.B) {
p := new([24 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [24 / 4]uint32{}
}
}
func BenchmarkClearFat32(b *testing.B) {
p := new([32 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [32 / 4]uint32{}
}
}
func BenchmarkClearFat40(b *testing.B) {
p := new([40 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [40 / 4]uint32{}
}
}
func BenchmarkClearFat48(b *testing.B) {
p := new([48 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [48 / 4]uint32{}
}
}
func BenchmarkClearFat56(b *testing.B) {
p := new([56 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [56 / 4]uint32{}
}
}
func BenchmarkClearFat64(b *testing.B) {
p := new([64 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [64 / 4]uint32{}
}
}
func BenchmarkClearFat72(b *testing.B) {
p := new([72 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [72 / 4]uint32{}
}
}
func BenchmarkClearFat128(b *testing.B) {
p := new([128 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [128 / 4]uint32{}
}
}
func BenchmarkClearFat256(b *testing.B) {
p := new([256 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [256 / 4]uint32{}
}
}
func BenchmarkClearFat512(b *testing.B) {
p := new([512 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [512 / 4]uint32{}
}
}
func BenchmarkClearFat1024(b *testing.B) {
p := new([1024 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [1024 / 4]uint32{}
}
}
func BenchmarkClearFat1032(b *testing.B) {
p := new([1032 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [1032 / 4]uint32{}
}
}
func BenchmarkClearFat1040(b *testing.B) {
p := new([1040 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = [1040 / 4]uint32{}
}
}
func BenchmarkCopyFat7(b *testing.B) {
var x [7]byte
p := new([7]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat8(b *testing.B) {
var x [8 / 4]uint32
p := new([8 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat11(b *testing.B) {
var x [11]byte
p := new([11]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat12(b *testing.B) {
var x [12 / 4]uint32
p := new([12 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat13(b *testing.B) {
var x [13]byte
p := new([13]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat14(b *testing.B) {
var x [14]byte
p := new([14]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat15(b *testing.B) {
var x [15]byte
p := new([15]byte)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat16(b *testing.B) {
var x [16 / 4]uint32
p := new([16 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat24(b *testing.B) {
var x [24 / 4]uint32
p := new([24 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat32(b *testing.B) {
var x [32 / 4]uint32
p := new([32 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat64(b *testing.B) {
var x [64 / 4]uint32
p := new([64 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat72(b *testing.B) {
var x [72 / 4]uint32
p := new([72 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat128(b *testing.B) {
var x [128 / 4]uint32
p := new([128 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat256(b *testing.B) {
var x [256 / 4]uint32
p := new([256 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat512(b *testing.B) {
var x [512 / 4]uint32
p := new([512 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat520(b *testing.B) {
var x [520 / 4]uint32
p := new([520 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat1024(b *testing.B) {
var x [1024 / 4]uint32
p := new([1024 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat1032(b *testing.B) {
var x [1032 / 4]uint32
p := new([1032 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
func BenchmarkCopyFat1040(b *testing.B) {
var x [1040 / 4]uint32
p := new([1040 / 4]uint32)
Escape(p)
b.ResetTimer()
for i := 0; i < b.N; i++ {
*p = x
}
}
// BenchmarkIssue18740 ensures that memmove uses 4 and 8 byte load/store to move 4 and 8 bytes.
// It used to do 2 2-byte load/stores, which leads to a pipeline stall
// when we try to read the result with one 4-byte load.
func BenchmarkIssue18740(b *testing.B) {
benchmarks := []struct {
name string
nbyte int
f func([]byte) uint64
}{
{"2byte", 2, func(buf []byte) uint64 { return uint64(binary.LittleEndian.Uint16(buf)) }},
{"4byte", 4, func(buf []byte) uint64 { return uint64(binary.LittleEndian.Uint32(buf)) }},
{"8byte", 8, func(buf []byte) uint64 { return binary.LittleEndian.Uint64(buf) }},
}
var g [4096]byte
for _, bm := range benchmarks {
buf := make([]byte, bm.nbyte)
b.Run(bm.name, func(b *testing.B) {
for j := 0; j < b.N; j++ {
for i := 0; i < 4096; i += bm.nbyte {
copy(buf[:], g[i:])
sink += bm.f(buf[:])
}
}
})
}
}