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// Copyright 2015 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 atomic_test
import (
"runtime"
"runtime/internal/atomic"
"runtime/internal/sys"
"testing"
"unsafe"
)
func runParallel(N, iter int, f func()) {
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(int(N)))
done := make(chan bool)
for i := 0; i < N; i++ {
go func() {
for j := 0; j < iter; j++ {
f()
}
done <- true
}()
}
for i := 0; i < N; i++ {
<-done
}
}
func TestXadduintptr(t *testing.T) {
N := 20
iter := 100000
if testing.Short() {
N = 10
iter = 10000
}
inc := uintptr(100)
total := uintptr(0)
runParallel(N, iter, func() {
atomic.Xadduintptr(&total, inc)
})
if want := uintptr(N*iter) * inc; want != total {
t.Fatalf("xadduintpr error, want %d, got %d", want, total)
}
total = 0
runParallel(N, iter, func() {
atomic.Xadduintptr(&total, inc)
atomic.Xadduintptr(&total, uintptr(-int64(inc)))
})
if total != 0 {
t.Fatalf("xadduintpr total error, want %d, got %d", 0, total)
}
}
// Tests that xadduintptr correctly updates 64-bit values. The place where
// we actually do so is mstats.go, functions mSysStat{Inc,Dec}.
func TestXadduintptrOnUint64(t *testing.T) {
if sys.BigEndian {
// On big endian architectures, we never use xadduintptr to update
// 64-bit values and hence we skip the test. (Note that functions
// mSysStat{Inc,Dec} in mstats.go have explicit checks for
// big-endianness.)
t.Skip("skip xadduintptr on big endian architecture")
}
const inc = 100
val := uint64(0)
atomic.Xadduintptr((*uintptr)(unsafe.Pointer(&val)), inc)
if inc != val {
t.Fatalf("xadduintptr should increase lower-order bits, want %d, got %d", inc, val)
}
}
func shouldPanic(t *testing.T, name string, f func()) {
defer func() {
if recover() == nil {
t.Errorf("%s did not panic", name)
}
}()
f()
}
// Variant of sync/atomic's TestUnaligned64:
func TestUnaligned64(t *testing.T) {
// Unaligned 64-bit atomics on 32-bit systems are
// a continual source of pain. Test that on 32-bit systems they crash
// instead of failing silently.
if unsafe.Sizeof(int(0)) != 4 {
t.Skip("test only runs on 32-bit systems")
}
x := make([]uint32, 4)
u := unsafe.Pointer(uintptr(unsafe.Pointer(&x[0])) | 4) // force alignment to 4
up64 := (*uint64)(u) // misaligned
p64 := (*int64)(u) // misaligned
shouldPanic(t, "Load64", func() { atomic.Load64(up64) })
shouldPanic(t, "Loadint64", func() { atomic.Loadint64(p64) })
shouldPanic(t, "Store64", func() { atomic.Store64(up64, 0) })
shouldPanic(t, "Xadd64", func() { atomic.Xadd64(up64, 1) })
shouldPanic(t, "Xchg64", func() { atomic.Xchg64(up64, 1) })
shouldPanic(t, "Cas64", func() { atomic.Cas64(up64, 1, 2) })
}
func TestAnd8(t *testing.T) {
// Basic sanity check.
x := uint8(0xff)
for i := uint8(0); i < 8; i++ {
atomic.And8(&x, ^(1 << i))
if r := uint8(0xff) << (i + 1); x != r {
t.Fatalf("clearing bit %#x: want %#x, got %#x", uint8(1<<i), r, x)
}
}
// Set every bit in array to 1.
a := make([]uint8, 1<<12)
for i := range a {
a[i] = 0xff
}
// Clear array bit-by-bit in different goroutines.
done := make(chan bool)
for i := 0; i < 8; i++ {
m := ^uint8(1 << i)
go func() {
for i := range a {
atomic.And8(&a[i], m)
}
done <- true
}()
}
for i := 0; i < 8; i++ {
<-done
}
// Check that the array has been totally cleared.
for i, v := range a {
if v != 0 {
t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint8(0), v)
}
}
}
func TestOr8(t *testing.T) {
// Basic sanity check.
x := uint8(0)
for i := uint8(0); i < 8; i++ {
atomic.Or8(&x, 1<<i)
if r := (uint8(1) << (i + 1)) - 1; x != r {
t.Fatalf("setting bit %#x: want %#x, got %#x", uint8(1)<<i, r, x)
}
}
// Start with every bit in array set to 0.
a := make([]uint8, 1<<12)
// Set every bit in array bit-by-bit in different goroutines.
done := make(chan bool)
for i := 0; i < 8; i++ {
m := uint8(1 << i)
go func() {
for i := range a {
atomic.Or8(&a[i], m)
}
done <- true
}()
}
for i := 0; i < 8; i++ {
<-done
}
// Check that the array has been totally set.
for i, v := range a {
if v != 0xff {
t.Fatalf("a[%v] not fully set: want %#x, got %#x", i, uint8(0xff), v)
}
}
}
func TestBitwiseContended(t *testing.T) {
// Start with every bit in array set to 0.
a := make([]uint8, 16)
// Iterations to try.
N := 1 << 16
if testing.Short() {
N = 1 << 10
}
// Set and then clear every bit in the array bit-by-bit in different goroutines.
done := make(chan bool)
for i := 0; i < 8; i++ {
m := uint8(1 << i)
go func() {
for n := 0; n < N; n++ {
for i := range a {
atomic.Or8(&a[i], m)
if atomic.Load8(&a[i])&m != m {
t.Errorf("a[%v] bit %#x not set", i, m)
}
atomic.And8(&a[i], ^m)
if atomic.Load8(&a[i])&m != 0 {
t.Errorf("a[%v] bit %#x not clear", i, m)
}
}
}
done <- true
}()
}
for i := 0; i < 8; i++ {
<-done
}
// Check that the array has been totally cleared.
for i, v := range a {
if v != 0 {
t.Fatalf("a[%v] not cleared: want %#x, got %#x", i, uint8(0), v)
}
}
}
func TestStorepNoWB(t *testing.T) {
var p [2]*int
for i := range p {
atomic.StorepNoWB(unsafe.Pointer(&p[i]), unsafe.Pointer(new(int)))
}
if p[0] == p[1] {
t.Error("Bad escape analysis of StorepNoWB")
}
}
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