Current File : //usr/local/go/src/runtime/memmove_test.go
// 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 uint32
go func() {
sp := unsafe.Pointer(&src[0])
dp := unsafe.Pointer(&dst[0])
atomic.StoreUint32(&ready, 1)
for i := 0; i < 10000; i++ {
Memmove(dp, sp, sz)
MemclrNoHeapPointers(dp, sz)
}
atomic.StoreUint32(&ready, 2)
}()
for atomic.LoadUint32(&ready) == 0 {
Gosched()
}
for atomic.LoadUint32(&ready) != 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 BenchmarkClearFat8(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [8 / 4]uint32
_ = x
}
}
func BenchmarkClearFat12(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [12 / 4]uint32
_ = x
}
}
func BenchmarkClearFat16(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [16 / 4]uint32
_ = x
}
}
func BenchmarkClearFat24(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [24 / 4]uint32
_ = x
}
}
func BenchmarkClearFat32(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [32 / 4]uint32
_ = x
}
}
func BenchmarkClearFat40(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [40 / 4]uint32
_ = x
}
}
func BenchmarkClearFat48(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [48 / 4]uint32
_ = x
}
}
func BenchmarkClearFat56(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [56 / 4]uint32
_ = x
}
}
func BenchmarkClearFat64(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [64 / 4]uint32
_ = x
}
}
func BenchmarkClearFat128(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [128 / 4]uint32
_ = x
}
}
func BenchmarkClearFat256(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [256 / 4]uint32
_ = x
}
}
func BenchmarkClearFat512(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [512 / 4]uint32
_ = x
}
}
func BenchmarkClearFat1024(b *testing.B) {
for i := 0; i < b.N; i++ {
var x [1024 / 4]uint32
_ = x
}
}
func BenchmarkCopyFat8(b *testing.B) {
var x [8 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat12(b *testing.B) {
var x [12 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat16(b *testing.B) {
var x [16 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat24(b *testing.B) {
var x [24 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat32(b *testing.B) {
var x [32 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat64(b *testing.B) {
var x [64 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat128(b *testing.B) {
var x [128 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat256(b *testing.B) {
var x [256 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat512(b *testing.B) {
var x [512 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat520(b *testing.B) {
var x [520 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
func BenchmarkCopyFat1024(b *testing.B) {
var x [1024 / 4]uint32
for i := 0; i < b.N; i++ {
y := x
_ = y
}
}
// 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[:])
}
}
})
}
}
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