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sync/atomic: add Store functions

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R=rsc
CC=golang-dev
https://golang.org/cl/4950060
This commit is contained in:
Dmitriy Vyukov 2011-09-07 21:50:51 +04:00
parent 299f524d90
commit 1fc676332f
5 changed files with 358 additions and 80 deletions
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18
src/pkg/sync/atomic/asm_386.s
View File

@ -18,6 +18,9 @@ TEXT ·CompareAndSwapUint32(SB),7,$0
TEXT ·CompareAndSwapUintptr(SB),7,$0
JMP ·CompareAndSwapUint32(SB)
TEXT ·CompareAndSwapPointer(SB),7,$0
JMP ·CompareAndSwapUint32(SB)
TEXT ·CompareAndSwapInt64(SB),7,$0
JMP ·CompareAndSwapUint64(SB)
@ -100,3 +103,18 @@ TEXT ·LoadUintptr(SB),7,$0
TEXT ·LoadPointer(SB),7,$0
JMP ·LoadUint32(SB)
TEXT ·StoreInt32(SB),7,$0
JMP ·StoreUint32(SB)
TEXT ·StoreUint32(SB),7,$0
MOVL addrptr+0(FP), BP
MOVL val+4(FP), AX
XCHGL AX, 0(BP)
RET
TEXT ·StoreUintptr(SB),7,$0
JMP ·StoreUint32(SB)
TEXT ·StorePointer(SB),7,$0
JMP ·StoreUint32(SB)

21
src/pkg/sync/atomic/asm_amd64.s
View File

@ -17,6 +17,9 @@ TEXT ·CompareAndSwapUint32(SB),7,$0
TEXT ·CompareAndSwapUintptr(SB),7,$0
JMP ·CompareAndSwapUint64(SB)
TEXT ·CompareAndSwapPointer(SB),7,$0
JMP ·CompareAndSwapUint64(SB)
TEXT ·CompareAndSwapInt64(SB),7,$0
JMP ·CompareAndSwapUint64(SB)
@ -75,3 +78,21 @@ TEXT ·LoadPointer(SB),7,$0
MOVQ 0(AX), AX
MOVQ AX, ret+8(FP)
RET
TEXT ·StoreInt32(SB),7,$0
JMP ·StoreUint32(SB)
TEXT ·StoreUint32(SB),7,$0
MOVQ addrptr+0(FP), BP
MOVL val+8(FP), AX
XCHGL AX, 0(BP)
RET
TEXT ·StoreUintptr(SB),7,$0
JMP ·StorePointer(SB)
TEXT ·StorePointer(SB),7,$0
MOVQ addrptr+0(FP), BP
MOVQ val+8(FP), AX
XCHGQ AX, 0(BP)
RET

21
src/pkg/sync/atomic/asm_linux_arm.s
View File

@ -50,6 +50,9 @@ cascheck:
TEXT ·CompareAndSwapUintptr(SB),7,$0
B ·CompareAndSwapUint32(SB)
TEXT ·CompareAndSwapPointer(SB),7,$0
B ·CompareAndSwapUint32(SB)
TEXT ·AddInt32(SB),7,$0
B ·AddUint32(SB)
@ -102,3 +105,21 @@ TEXT ·LoadUintptr(SB),7,$0
TEXT ·LoadPointer(SB),7,$0
B ·LoadUint32(SB)
TEXT ·StoreInt32(SB),7,$0
B ·StoreUint32(SB)
TEXT ·StoreUint32(SB),7,$0
MOVW addrptr+0(FP), R2
MOVW val+4(FP), R1
storeloop1:
MOVW 0(R2), R0
BL cas<>(SB)
BCC storeloop1
RET
TEXT ·StoreUintptr(SB),7,$0
B ·StoreUint32(SB)
TEXT ·StorePointer(SB),7,$0
B ·StoreUint32(SB)

291
src/pkg/sync/atomic/atomic_test.go
View File

@ -164,17 +164,17 @@ func TestCompareAndSwapInt32(t *testing.T) {
for val := int32(1); val+val > val; val += val {
x.i = val
if !CompareAndSwapInt32(&x.i, val, val+1) {
t.Errorf("should have swapped %#x %#x", val, val+1)
t.Fatalf("should have swapped %#x %#x", val, val+1)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
x.i = val + 1
if CompareAndSwapInt32(&x.i, val, val+2) {
t.Errorf("should not have swapped %#x %#x", val, val+2)
t.Fatalf("should not have swapped %#x %#x", val, val+2)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
}
if x.before != magic32 || x.after != magic32 {
@ -193,17 +193,17 @@ func TestCompareAndSwapUint32(t *testing.T) {
for val := uint32(1); val+val > val; val += val {
x.i = val
if !CompareAndSwapUint32(&x.i, val, val+1) {
t.Errorf("should have swapped %#x %#x", val, val+1)
t.Fatalf("should have swapped %#x %#x", val, val+1)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
x.i = val + 1
if CompareAndSwapUint32(&x.i, val, val+2) {
t.Errorf("should not have swapped %#x %#x", val, val+2)
t.Fatalf("should not have swapped %#x %#x", val, val+2)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
}
if x.before != magic32 || x.after != magic32 {
@ -226,17 +226,17 @@ func TestCompareAndSwapInt64(t *testing.T) {
for val := int64(1); val+val > val; val += val {
x.i = val
if !CompareAndSwapInt64(&x.i, val, val+1) {
t.Errorf("should have swapped %#x %#x", val, val+1)
t.Fatalf("should have swapped %#x %#x", val, val+1)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
x.i = val + 1
if CompareAndSwapInt64(&x.i, val, val+2) {
t.Errorf("should not have swapped %#x %#x", val, val+2)
t.Fatalf("should not have swapped %#x %#x", val, val+2)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
}
if x.before != magic64 || x.after != magic64 {
@ -259,17 +259,17 @@ func TestCompareAndSwapUint64(t *testing.T) {
for val := uint64(1); val+val > val; val += val {
x.i = val
if !CompareAndSwapUint64(&x.i, val, val+1) {
t.Errorf("should have swapped %#x %#x", val, val+1)
t.Fatalf("should have swapped %#x %#x", val, val+1)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
x.i = val + 1
if CompareAndSwapUint64(&x.i, val, val+2) {
t.Errorf("should not have swapped %#x %#x", val, val+2)
t.Fatalf("should not have swapped %#x %#x", val, val+2)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
}
if x.before != magic64 || x.after != magic64 {
@ -290,17 +290,48 @@ func TestCompareAndSwapUintptr(t *testing.T) {
for val := uintptr(1); val+val > val; val += val {
x.i = val
if !CompareAndSwapUintptr(&x.i, val, val+1) {
t.Errorf("should have swapped %#x %#x", val, val+1)
t.Fatalf("should have swapped %#x %#x", val, val+1)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
x.i = val + 1
if CompareAndSwapUintptr(&x.i, val, val+2) {
t.Errorf("should not have swapped %#x %#x", val, val+2)
t.Fatalf("should not have swapped %#x %#x", val, val+2)
}
if x.i != val+1 {
t.Errorf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
}
}
func TestCompareAndSwapPointer(t *testing.T) {
var x struct {
before uintptr
i unsafe.Pointer
after uintptr
}
var m uint64 = magic64
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
for val := uintptr(1); val+val > val; val += val {
x.i = unsafe.Pointer(val)
if !CompareAndSwapPointer(&x.i, unsafe.Pointer(val), unsafe.Pointer(val+1)) {
t.Fatalf("should have swapped %#x %#x", val, val+1)
}
if x.i != unsafe.Pointer(val+1) {
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
x.i = unsafe.Pointer(val + 1)
if CompareAndSwapPointer(&x.i, unsafe.Pointer(val), unsafe.Pointer(val+2)) {
t.Fatalf("should not have swapped %#x %#x", val, val+2)
}
if x.i != unsafe.Pointer(val+1) {
t.Fatalf("wrong x.i after swap: x.i=%#x val+1=%#x", x.i, val+1)
}
}
if x.before != magicptr || x.after != magicptr {
@ -392,6 +423,94 @@ func TestLoadPointer(t *testing.T) {
}
}
func TestStoreInt32(t *testing.T) {
var x struct {
before int32
i int32
after int32
}
x.before = magic32
x.after = magic32
v := int32(0)
for delta := int32(1); delta+delta > delta; delta += delta {
StoreInt32(&x.i, v)
if x.i != v {
t.Fatalf("delta=%d i=%d v=%d", delta, x.i, v)
}
v += delta
}
if x.before != magic32 || x.after != magic32 {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magic32, magic32)
}
}
func TestStoreUint32(t *testing.T) {
var x struct {
before uint32
i uint32
after uint32
}
x.before = magic32
x.after = magic32
v := uint32(0)
for delta := uint32(1); delta+delta > delta; delta += delta {
StoreUint32(&x.i, v)
if x.i != v {
t.Fatalf("delta=%d i=%d v=%d", delta, x.i, v)
}
v += delta
}
if x.before != magic32 || x.after != magic32 {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magic32, magic32)
}
}
func TestStoreUintptr(t *testing.T) {
var x struct {
before uintptr
i uintptr
after uintptr
}
var m uint64 = magic64
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
v := uintptr(0)
for delta := uintptr(1); delta+delta > delta; delta += delta {
StoreUintptr(&x.i, v)
if x.i != v {
t.Fatalf("delta=%d i=%d v=%d", delta, x.i, v)
}
v += delta
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
}
}
func TestStorePointer(t *testing.T) {
var x struct {
before uintptr
i unsafe.Pointer
after uintptr
}
var m uint64 = magic64
magicptr := uintptr(m)
x.before = magicptr
x.after = magicptr
v := unsafe.Pointer(uintptr(0))
for delta := uintptr(1); delta+delta > delta; delta += delta {
StorePointer(&x.i, unsafe.Pointer(v))
if x.i != v {
t.Fatalf("delta=%d i=%d v=%d", delta, x.i, v)
}
v = unsafe.Pointer(uintptr(v) + delta)
}
if x.before != magicptr || x.after != magicptr {
t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, magicptr, magicptr)
}
}
// Tests of correct behavior, with contention.
// (Is the function atomic?)
//
@ -410,6 +529,7 @@ var hammer32 = []struct {
{"CompareAndSwapInt32", hammerCompareAndSwapInt32},
{"CompareAndSwapUint32", hammerCompareAndSwapUint32},
{"CompareAndSwapUintptr", hammerCompareAndSwapUintptr32},
{"CompareAndSwapPointer", hammerCompareAndSwapPointer32},
}
func init() {
@ -480,6 +600,20 @@ func hammerCompareAndSwapUintptr32(uval *uint32, count int) {
}
}
func hammerCompareAndSwapPointer32(uval *uint32, count int) {
// only safe when uintptr is 32-bit.
// not called on 64-bit systems.
val := (*unsafe.Pointer)(unsafe.Pointer(uval))
for i := 0; i < count; i++ {
for {
v := *val
if CompareAndSwapPointer(val, v, unsafe.Pointer(uintptr(v)+1)) {
break
}
}
}
}
func TestHammer32(t *testing.T) {
const p = 4
n := 100000
@ -504,7 +638,7 @@ func TestHammer32(t *testing.T) {
<-c
}
if val != uint32(n)*p {
t.Errorf("%s: val=%d want %d", tt.name, val, n*p)
t.Fatalf("%s: val=%d want %d", tt.name, val, n*p)
}
}
}
@ -519,6 +653,7 @@ var hammer64 = []struct {
{"CompareAndSwapInt64", hammerCompareAndSwapInt64},
{"CompareAndSwapUint64", hammerCompareAndSwapUint64},
{"CompareAndSwapUintptr", hammerCompareAndSwapUintptr64},
{"CompareAndSwapPointer", hammerCompareAndSwapPointer64},
}
func init() {
@ -589,6 +724,20 @@ func hammerCompareAndSwapUintptr64(uval *uint64, count int) {
}
}
func hammerCompareAndSwapPointer64(uval *uint64, count int) {
// only safe when uintptr is 64-bit.
// not called on 32-bit systems.
val := (*unsafe.Pointer)(unsafe.Pointer(uval))
for i := 0; i < count; i++ {
for {
v := *val
if CompareAndSwapPointer(val, v, unsafe.Pointer(uintptr(v)+1)) {
break
}
}
}
}
func TestHammer64(t *testing.T) {
if test64err != nil {
t.Logf("Skipping 64-bit tests: %v", test64err)
@ -617,14 +766,13 @@ func TestHammer64(t *testing.T) {
<-c
}
if val != uint64(n)*p {
t.Errorf("%s: val=%d want %d", tt.name, val, n*p)
t.Fatalf("%s: val=%d want %d", tt.name, val, n*p)
}
}
}
func hammerLoadInt32(t *testing.T, valp unsafe.Pointer) {
func hammerStoreLoadInt32(t *testing.T, valp unsafe.Pointer) {
val := (*int32)(valp)
for {
v := LoadInt32(val)
vlo := v & ((1 << 16) - 1)
vhi := v >> 16
@ -635,15 +783,11 @@ func hammerLoadInt32(t *testing.T, valp unsafe.Pointer) {
if vlo == 1e4 {
new = 0
}
if CompareAndSwapInt32(val, v, new) {
break
}
}
StoreInt32(val, new)
}
func hammerLoadUint32(t *testing.T, valp unsafe.Pointer) {
func hammerStoreLoadUint32(t *testing.T, valp unsafe.Pointer) {
val := (*uint32)(valp)
for {
v := LoadUint32(val)
vlo := v & ((1 << 16) - 1)
vhi := v >> 16
@ -654,17 +798,13 @@ func hammerLoadUint32(t *testing.T, valp unsafe.Pointer) {
if vlo == 1e4 {
new = 0
}
if CompareAndSwapUint32(val, v, new) {
break
}
}
StoreUint32(val, new)
}
func hammerLoadUintptr(t *testing.T, valp unsafe.Pointer) {
func hammerStoreLoadUintptr(t *testing.T, valp unsafe.Pointer) {
val := (*uintptr)(valp)
var test64 uint64 = 1 << 50
arch32 := uintptr(test64) == 0
for {
v := LoadUintptr(val)
new := v
if arch32 {
@ -686,17 +826,43 @@ func hammerLoadUintptr(t *testing.T, valp unsafe.Pointer) {
inc := uint64(1 + 1<<32)
new = v + uintptr(inc)
}
if CompareAndSwapUintptr(val, v, new) {
break
}
}
StoreUintptr(val, new)
}
func TestHammerLoad(t *testing.T) {
tests := [...]func(*testing.T, unsafe.Pointer){hammerLoadInt32, hammerLoadUint32, hammerLoadUintptr}
n := 100000
func hammerStoreLoadPointer(t *testing.T, valp unsafe.Pointer) {
val := (*unsafe.Pointer)(valp)
var test64 uint64 = 1 << 50
arch32 := uintptr(test64) == 0
v := uintptr(LoadPointer(val))
new := v
if arch32 {
vlo := v & ((1 << 16) - 1)
vhi := v >> 16
if vlo != vhi {
t.Fatalf("LoadUintptr: %#x != %#x", vlo, vhi)
}
new = v + 1 + 1<<16
if vlo == 1e4 {
new = 0
}
} else {
vlo := v & ((1 << 32) - 1)
vhi := v >> 32
if vlo != vhi {
t.Fatalf("LoadUintptr: %#x != %#x", vlo, vhi)
}
inc := uint64(1 + 1<<32)
new = v + uintptr(inc)
}
StorePointer(val, unsafe.Pointer(new))
}
func TestHammerStoreLoad(t *testing.T) {
tests := [...]func(*testing.T, unsafe.Pointer){hammerStoreLoadInt32, hammerStoreLoadUint32,
hammerStoreLoadUintptr, hammerStoreLoadPointer}
n := int(1e6)
if testing.Short() {
n = 10000
n = int(1e4)
}
const procs = 8
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(procs))
@ -716,3 +882,40 @@ func TestHammerLoad(t *testing.T) {
}
}
}
func TestStoreLoadSeqCst(t *testing.T) {
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
N := int32(1e6)
if testing.Short() {
N = int32(1e5)
}
c := make(chan bool, 2)
X := [2]int32{}
ack := [2][3]int32{{-1, -1, -1}, {-1, -1, -1}}
for p := 0; p < 2; p++ {
go func(me int) {
he := 1 - me
for i := int32(1); i < N; i++ {
StoreInt32(&X[me], i)
my := LoadInt32(&X[he])
ack[me][i%3] = my
for w := 1; ack[he][i%3] == -1; w++ {
if w%1000 == 0 {
runtime.Gosched()
}
}
his := ack[he][i%3]
if (my != i && my != i-1) || (his != i && his != i-1) {
t.Fatalf("invalid values: %d/%d (%d)", my, his, i)
}
if my != i && his != i {
t.Fatalf("store/load are not sequentially consistent: %d/%d (%d)", my, his, i)
}
ack[me][(i-1)%3] = -1
}
c <- true
}(p)
}
<-c
<-c
}

15
src/pkg/sync/atomic/doc.go
View File

@ -45,6 +45,9 @@ func CompareAndSwapUint64(val *uint64, old, new uint64) (swapped bool)
// CompareAndSwapUintptr executes the compare-and-swap operation for a uintptr value.
func CompareAndSwapUintptr(val *uintptr, old, new uintptr) (swapped bool)
// CompareAndSwapPointer executes the compare-and-swap operation for a unsafe.Pointer value.
func CompareAndSwapPointer(val *unsafe.Pointer, old, new unsafe.Pointer) (swapped bool)
// AddInt32 atomically adds delta to *val and returns the new value.
func AddInt32(val *int32, delta int32) (new int32)
@ -72,6 +75,18 @@ func LoadUintptr(addr *uintptr) (val uintptr)
// LoadPointer atomically loads *addr.
func LoadPointer(addr *unsafe.Pointer) (val unsafe.Pointer)
// StoreInt32 atomically stores val into *addr.
func StoreInt32(addr *int32, val int32)
// StoreUint32 atomically stores val into *addr.
func StoreUint32(addr *uint32, val uint32)
// StoreUintptr atomically stores val into *addr.
func StoreUintptr(addr *uintptr, val uintptr)
// StorePointer atomically stores val into *addr.
func StorePointer(addr *unsafe.Pointer, val unsafe.Pointer)
// Helper for ARM. Linker will discard on other systems
func panic64() {
panic("sync/atomic: broken 64-bit atomic operations (buggy QEMU)")