src/runtime/internal/atomic/atomic_test.go - go - Git at Google

 // 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 (
 	"internal/goarch"
 	"runtime"
 	"runtime/internal/atomic"
 	"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 goarch.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() {
 		// Check that all GC maps are sane.
 		runtime.GC()

 		err := recover()
 		want := "unaligned 64-bit atomic operation"
 		if err == nil {
 			t.Errorf("%s did not panic", name)
 		} else if s, _ := err.(string); s != want {
 			t.Errorf("%s: wanted panic %q, got %q", name, want, err)
 		}
 	}()
 	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 TestAnd(t *testing.T) {
 	// Basic sanity check.
 	x := uint32(0xffffffff)
 	for i := uint32(0); i < 32; i++ {
 		atomic.And(&x, ^(1 << i))
 		if r := uint32(0xffffffff) << (i + 1); x != r {
 			t.Fatalf("clearing bit %#x: want %#x, got %#x", uint32(1<<i), r, x)
 		}
 	}

 	// Set every bit in array to 1.
 	a := make([]uint32, 1<<12)
 	for i := range a {
 		a[i] = 0xffffffff
 	}

 	// Clear array bit-by-bit in different goroutines.
 	done := make(chan bool)
 	for i := 0; i < 32; i++ {
 		m := ^uint32(1 << i)
 		go func() {
 			for i := range a {
 				atomic.And(&a[i], m)
 			}
 			done <- true
 		}()
 	}
 	for i := 0; i < 32; 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, uint32(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 TestOr(t *testing.T) {
 	// Basic sanity check.
 	x := uint32(0)
 	for i := uint32(0); i < 32; i++ {
 		atomic.Or(&x, 1<<i)
 		if r := (uint32(1) << (i + 1)) - 1; x != r {
 			t.Fatalf("setting bit %#x: want %#x, got %#x", uint32(1)<<i, r, x)
 		}
 	}

 	// Start with every bit in array set to 0.
 	a := make([]uint32, 1<<12)

 	// Set every bit in array bit-by-bit in different goroutines.
 	done := make(chan bool)
 	for i := 0; i < 32; i++ {
 		m := uint32(1 << i)
 		go func() {
 			for i := range a {
 				atomic.Or(&a[i], m)
 			}
 			done <- true
 		}()
 	}
 	for i := 0; i < 32; i++ {
 		<-done
 	}

 	// Check that the array has been totally set.
 	for i, v := range a {
 		if v != 0xffffffff {
 			t.Fatalf("a[%v] not fully set: want %#x, got %#x", i, uint32(0xffffffff), v)
 		}
 	}
 }

 func TestBitwiseContended8(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 TestBitwiseContended(t *testing.T) {
 	// Start with every bit in array set to 0.
 	a := make([]uint32, 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 < 32; i++ {
 		m := uint32(1 << i)
 		go func() {
 			for n := 0; n < N; n++ {
 				for i := range a {
 					atomic.Or(&a[i], m)
 					if atomic.Load(&a[i])&m != m {
 						t.Errorf("a[%v] bit %#x not set", i, m)
 					}
 					atomic.And(&a[i], ^m)
 					if atomic.Load(&a[i])&m != 0 {
 						t.Errorf("a[%v] bit %#x not clear", i, m)
 					}
 				}
 			}
 			done <- true
 		}()
 	}
 	for i := 0; i < 32; 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, uint32(0), v)
 		}
 	}
 }

 func TestCasRel(t *testing.T) {
 	const _magic = 0x5a5aa5a5
 	var x struct {
 		before uint32
 		i      uint32
 		after  uint32
 		o      uint32
 		n      uint32
 	}

 	x.before = _magic
 	x.after = _magic
 	for j := 0; j < 32; j += 1 {
 		x.i = (1 << j) + 0
 		x.o = (1 << j) + 0
 		x.n = (1 << j) + 1
 		if !atomic.CasRel(&x.i, x.o, x.n) {
 			t.Fatalf("should have swapped %#x %#x", x.o, x.n)
 		}

 		if x.i != x.n {
 			t.Fatalf("wrong x.i after swap: x.i=%#x x.n=%#x", x.i, x.n)
 		}

 		if x.before != _magic || x.after != _magic {
 			t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, _magic, _magic)
 		}
 	}
 }

 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")
 	}
 }
	// 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 (
	"internal/goarch"
	"runtime"
	"runtime/internal/atomic"
	"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(Niter) 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 goarch.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() {
	// Check that all GC maps are sane.
	runtime.GC()

	err := recover()
	want := "unaligned 64-bit atomic operation"
	if err == nil {
	t.Errorf("%s did not panic", name)
	} else if s, _ := err.(string); s != want {
	t.Errorf("%s: wanted panic %q, got %q", name, want, err)
	}
	}()
	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 TestAnd(t *testing.T) {
	// Basic sanity check.
	x := uint32(0xffffffff)
	for i := uint32(0); i < 32; i++ {
	atomic.And(&x, ^(1 << i))
	if r := uint32(0xffffffff) << (i + 1); x != r {
	t.Fatalf("clearing bit %#x: want %#x, got %#x", uint32(1<<i), r, x)
	}
	}

	// Set every bit in array to 1.
	a := make([]uint32, 1<<12)
	for i := range a {
	a[i] = 0xffffffff
	}

	// Clear array bit-by-bit in different goroutines.
	done := make(chan bool)
	for i := 0; i < 32; i++ {
	m := ^uint32(1 << i)
	go func() {
	for i := range a {
	atomic.And(&a[i], m)
	}
	done <- true
	}()
	}
	for i := 0; i < 32; 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, uint32(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 TestOr(t *testing.T) {
	// Basic sanity check.
	x := uint32(0)
	for i := uint32(0); i < 32; i++ {
	atomic.Or(&x, 1<<i)
	if r := (uint32(1) << (i + 1)) - 1; x != r {
	t.Fatalf("setting bit %#x: want %#x, got %#x", uint32(1)<<i, r, x)
	}
	}

	// Start with every bit in array set to 0.
	a := make([]uint32, 1<<12)

	// Set every bit in array bit-by-bit in different goroutines.
	done := make(chan bool)
	for i := 0; i < 32; i++ {
	m := uint32(1 << i)
	go func() {
	for i := range a {
	atomic.Or(&a[i], m)
	}
	done <- true
	}()
	}
	for i := 0; i < 32; i++ {
	<-done
	}

	// Check that the array has been totally set.
	for i, v := range a {
	if v != 0xffffffff {
	t.Fatalf("a[%v] not fully set: want %#x, got %#x", i, uint32(0xffffffff), v)
	}
	}
	}

	func TestBitwiseContended8(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 TestBitwiseContended(t *testing.T) {
	// Start with every bit in array set to 0.
	a := make([]uint32, 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 < 32; i++ {
	m := uint32(1 << i)
	go func() {
	for n := 0; n < N; n++ {
	for i := range a {
	atomic.Or(&a[i], m)
	if atomic.Load(&a[i])&m != m {
	t.Errorf("a[%v] bit %#x not set", i, m)
	}
	atomic.And(&a[i], ^m)
	if atomic.Load(&a[i])&m != 0 {
	t.Errorf("a[%v] bit %#x not clear", i, m)
	}
	}
	}
	done <- true
	}()
	}
	for i := 0; i < 32; 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, uint32(0), v)
	}
	}
	}

	func TestCasRel(t *testing.T) {
	const _magic = 0x5a5aa5a5
	var x struct {
	before uint32
	i uint32
	after uint32
	o uint32
	n uint32
	}

	x.before = _magic
	x.after = _magic
	for j := 0; j < 32; j += 1 {
	x.i = (1 << j) + 0
	x.o = (1 << j) + 0
	x.n = (1 << j) + 1
	if !atomic.CasRel(&x.i, x.o, x.n) {
	t.Fatalf("should have swapped %#x %#x", x.o, x.n)
	}

	if x.i != x.n {
	t.Fatalf("wrong x.i after swap: x.i=%#x x.n=%#x", x.i, x.n)
	}

	if x.before != _magic \|\| x.after != _magic {
	t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, _magic, _magic)
	}
	}
	}

	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")
	}
	}