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-rw-r--r--src/pkg/sync/atomic/asm_386.s14
-rw-r--r--src/pkg/sync/atomic/asm_amd64.s4
-rw-r--r--src/pkg/sync/atomic/asm_amd64p32.s159
-rw-r--r--src/pkg/sync/atomic/asm_linux_arm.s12
-rw-r--r--src/pkg/sync/atomic/atomic_test.go7
-rw-r--r--src/pkg/sync/atomic/export_linux_arm_test.go2
-rw-r--r--src/pkg/sync/mutex_test.go72
-rw-r--r--src/pkg/sync/once_test.go25
-rw-r--r--src/pkg/sync/pool.go223
-rw-r--r--src/pkg/sync/pool_test.go151
-rw-r--r--src/pkg/sync/runtime_sema_test.go85
-rw-r--r--src/pkg/sync/rwmutex_test.go79
-rw-r--r--src/pkg/sync/waitgroup.go10
-rw-r--r--src/pkg/sync/waitgroup_test.go125
14 files changed, 695 insertions, 273 deletions
diff --git a/src/pkg/sync/atomic/asm_386.s b/src/pkg/sync/atomic/asm_386.s
index eaa72eabb..807c2f873 100644
--- a/src/pkg/sync/atomic/asm_386.s
+++ b/src/pkg/sync/atomic/asm_386.s
@@ -13,7 +13,7 @@ TEXT ·SwapUint32(SB),NOSPLIT,$0-12
MOVL addr+0(FP), BP
MOVL new+4(FP), AX
XCHGL AX, 0(BP)
- MOVL AX, new+8(FP)
+ MOVL AX, old+8(FP)
RET
TEXT ·SwapInt64(SB),NOSPLIT,$0-20
@@ -43,8 +43,8 @@ swaploop:
// success
// return DX:AX
- MOVL AX, new_lo+12(FP)
- MOVL DX, new_hi+16(FP)
+ MOVL AX, old_lo+12(FP)
+ MOVL DX, old_hi+16(FP)
RET
TEXT ·SwapUintptr(SB),NOSPLIT,$0-12
@@ -155,10 +155,10 @@ TEXT ·LoadUint32(SB),NOSPLIT,$0-8
MOVL AX, val+4(FP)
RET
-TEXT ·LoadInt64(SB),NOSPLIT,$0-16
+TEXT ·LoadInt64(SB),NOSPLIT,$0-12
JMP ·LoadUint64(SB)
-TEXT ·LoadUint64(SB),NOSPLIT,$0-16
+TEXT ·LoadUint64(SB),NOSPLIT,$0-12
MOVL addr+0(FP), AX
TESTL $7, AX
JZ 2(PC)
@@ -186,10 +186,10 @@ TEXT ·StoreUint32(SB),NOSPLIT,$0-8
XCHGL AX, 0(BP)
RET
-TEXT ·StoreInt64(SB),NOSPLIT,$0-16
+TEXT ·StoreInt64(SB),NOSPLIT,$0-12
JMP ·StoreUint64(SB)
-TEXT ·StoreUint64(SB),NOSPLIT,$0-16
+TEXT ·StoreUint64(SB),NOSPLIT,$0-12
MOVL addr+0(FP), AX
TESTL $7, AX
JZ 2(PC)
diff --git a/src/pkg/sync/atomic/asm_amd64.s b/src/pkg/sync/atomic/asm_amd64.s
index 0900492dc..77afa129e 100644
--- a/src/pkg/sync/atomic/asm_amd64.s
+++ b/src/pkg/sync/atomic/asm_amd64.s
@@ -13,7 +13,7 @@ TEXT ·SwapUint32(SB),NOSPLIT,$0-20
MOVQ addr+0(FP), BP
MOVL new+8(FP), AX
XCHGL AX, 0(BP)
- MOVL AX, new+16(FP)
+ MOVL AX, old+16(FP)
RET
TEXT ·SwapInt64(SB),NOSPLIT,$0-24
@@ -23,7 +23,7 @@ TEXT ·SwapUint64(SB),NOSPLIT,$0-24
MOVQ addr+0(FP), BP
MOVQ new+8(FP), AX
XCHGQ AX, 0(BP)
- MOVQ AX, new+16(FP)
+ MOVQ AX, old+16(FP)
RET
TEXT ·SwapUintptr(SB),NOSPLIT,$0-24
diff --git a/src/pkg/sync/atomic/asm_amd64p32.s b/src/pkg/sync/atomic/asm_amd64p32.s
new file mode 100644
index 000000000..b24ae7a59
--- /dev/null
+++ b/src/pkg/sync/atomic/asm_amd64p32.s
@@ -0,0 +1,159 @@
+// Copyright 2011 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.
+
+#include "../../../cmd/ld/textflag.h"
+
+TEXT ·SwapInt32(SB),NOSPLIT,$0-12
+ JMP ·SwapUint32(SB)
+
+TEXT ·SwapUint32(SB),NOSPLIT,$0-12
+ MOVL addr+0(FP), BX
+ MOVL new+4(FP), AX
+ XCHGL AX, 0(BX)
+ MOVL AX, old+8(FP)
+ RET
+
+TEXT ·SwapInt64(SB),NOSPLIT,$0-24
+ JMP ·SwapUint64(SB)
+
+TEXT ·SwapUint64(SB),NOSPLIT,$0-24
+ MOVL addr+0(FP), BX
+ TESTL $7, BX
+ JZ 2(PC)
+ MOVL 0, BX // crash with nil ptr deref
+ MOVQ new+8(FP), AX
+ XCHGQ AX, 0(BX)
+ MOVQ AX, old+16(FP)
+ RET
+
+TEXT ·SwapUintptr(SB),NOSPLIT,$0-12
+ JMP ·SwapUint32(SB)
+
+TEXT ·SwapPointer(SB),NOSPLIT,$0-12
+ JMP ·SwapUint32(SB)
+
+TEXT ·CompareAndSwapInt32(SB),NOSPLIT,$0-17
+ JMP ·CompareAndSwapUint32(SB)
+
+TEXT ·CompareAndSwapUint32(SB),NOSPLIT,$0-17
+ MOVL addr+0(FP), BX
+ MOVL old+4(FP), AX
+ MOVL new+8(FP), CX
+ LOCK
+ CMPXCHGL CX, 0(BX)
+ SETEQ swapped+16(FP)
+ RET
+
+TEXT ·CompareAndSwapUintptr(SB),NOSPLIT,$0-17
+ JMP ·CompareAndSwapUint32(SB)
+
+TEXT ·CompareAndSwapPointer(SB),NOSPLIT,$0-17
+ JMP ·CompareAndSwapUint32(SB)
+
+TEXT ·CompareAndSwapInt64(SB),NOSPLIT,$0-25
+ JMP ·CompareAndSwapUint64(SB)
+
+TEXT ·CompareAndSwapUint64(SB),NOSPLIT,$0-25
+ MOVL addr+0(FP), BX
+ TESTL $7, BX
+ JZ 2(PC)
+ MOVL 0, BX // crash with nil ptr deref
+ MOVQ old+8(FP), AX
+ MOVQ new+16(FP), CX
+ LOCK
+ CMPXCHGQ CX, 0(BX)
+ SETEQ swapped+24(FP)
+ RET
+
+TEXT ·AddInt32(SB),NOSPLIT,$0-12
+ JMP ·AddUint32(SB)
+
+TEXT ·AddUint32(SB),NOSPLIT,$0-12
+ MOVL addr+0(FP), BX
+ MOVL delta+4(FP), AX
+ MOVL AX, CX
+ LOCK
+ XADDL AX, 0(BX)
+ ADDL AX, CX
+ MOVL CX, new+8(FP)
+ RET
+
+TEXT ·AddUintptr(SB),NOSPLIT,$0-12
+ JMP ·AddUint32(SB)
+
+TEXT ·AddInt64(SB),NOSPLIT,$0-24
+ JMP ·AddUint64(SB)
+
+TEXT ·AddUint64(SB),NOSPLIT,$0-24
+ MOVL addr+0(FP), BX
+ TESTL $7, BX
+ JZ 2(PC)
+ MOVL 0, BX // crash with nil ptr deref
+ MOVQ delta+8(FP), AX
+ MOVQ AX, CX
+ LOCK
+ XADDQ AX, 0(BX)
+ ADDQ AX, CX
+ MOVQ CX, new+16(FP)
+ RET
+
+TEXT ·LoadInt32(SB),NOSPLIT,$0-12
+ JMP ·LoadUint32(SB)
+
+TEXT ·LoadUint32(SB),NOSPLIT,$0-12
+ MOVL addr+0(FP), AX
+ MOVL 0(AX), AX
+ MOVL AX, val+8(FP)
+ RET
+
+TEXT ·LoadInt64(SB),NOSPLIT,$0-16
+ JMP ·LoadUint64(SB)
+
+TEXT ·LoadUint64(SB),NOSPLIT,$0-16
+ MOVL addr+0(FP), AX
+ TESTL $7, AX
+ JZ 2(PC)
+ MOVL 0, AX // crash with nil ptr deref
+ MOVQ 0(AX), AX
+ MOVQ AX, val+8(FP)
+ RET
+
+TEXT ·LoadUintptr(SB),NOSPLIT,$0-12
+ JMP ·LoadPointer(SB)
+
+TEXT ·LoadPointer(SB),NOSPLIT,$0-12
+ MOVL addr+0(FP), AX
+ MOVL 0(AX), AX
+ MOVL AX, val+8(FP)
+ RET
+
+TEXT ·StoreInt32(SB),NOSPLIT,$0-8
+ JMP ·StoreUint32(SB)
+
+TEXT ·StoreUint32(SB),NOSPLIT,$0-8
+ MOVL addr+0(FP), BX
+ MOVL val+4(FP), AX
+ XCHGL AX, 0(BX)
+ RET
+
+TEXT ·StoreInt64(SB),NOSPLIT,$0-16
+ JMP ·StoreUint64(SB)
+
+TEXT ·StoreUint64(SB),NOSPLIT,$0-16
+ MOVL addr+0(FP), BX
+ TESTL $7, BX
+ JZ 2(PC)
+ MOVL 0, BX // crash with nil ptr deref
+ MOVQ val+8(FP), AX
+ XCHGQ AX, 0(BX)
+ RET
+
+TEXT ·StoreUintptr(SB),NOSPLIT,$0-8
+ JMP ·StorePointer(SB)
+
+TEXT ·StorePointer(SB),NOSPLIT,$0-8
+ MOVL addr+0(FP), BX
+ MOVL val+4(FP), AX
+ XCHGL AX, 0(BX)
+ RET
diff --git a/src/pkg/sync/atomic/asm_linux_arm.s b/src/pkg/sync/atomic/asm_linux_arm.s
index b85ca0a13..27be57aa1 100644
--- a/src/pkg/sync/atomic/asm_linux_arm.s
+++ b/src/pkg/sync/atomic/asm_linux_arm.s
@@ -42,7 +42,7 @@ casagain:
BCC cascheck
MOVW $1, R0
casret:
- MOVW R0, ret+12(FP)
+ MOVB R0, swapped+12(FP)
RET
cascheck:
// Kernel lies; double-check.
@@ -73,7 +73,7 @@ addloop1:
ADD R4, R1
BL cas<>(SB)
BCC addloop1
- MOVW R1, ret+8(FP)
+ MOVW R1, new+8(FP)
RET
TEXT ·AddUintptr(SB),NOSPLIT,$0
@@ -132,13 +132,13 @@ TEXT ·generalCAS64(SB),NOSPLIT,$20-21
BEQ 2(PC)
MOVW R1, (R1)
MOVW R0, 4(R13)
- MOVW oldlo+4(FP), R1
+ MOVW old_lo+4(FP), R1
MOVW R1, 8(R13)
- MOVW oldhi+8(FP), R1
+ MOVW old_hi+8(FP), R1
MOVW R1, 12(R13)
- MOVW newlo+12(FP), R2
+ MOVW new_lo+12(FP), R2
MOVW R2, 16(R13)
- MOVW newhi+16(FP), R3
+ MOVW new_hi+16(FP), R3
MOVW R3, 20(R13)
BL runtime·cas64(SB)
MOVB R0, ret+20(FP)
diff --git a/src/pkg/sync/atomic/atomic_test.go b/src/pkg/sync/atomic/atomic_test.go
index e10effe7e..a5f44f70d 100644
--- a/src/pkg/sync/atomic/atomic_test.go
+++ b/src/pkg/sync/atomic/atomic_test.go
@@ -813,7 +813,7 @@ func hammerSwapUintptr32(uaddr *uint32, count int) {
new := uintptr(seed+i)<<16 | uintptr(seed+i)<<16>>16
old := SwapUintptr(addr, new)
if old>>16 != old<<16>>16 {
- panic(fmt.Sprintf("SwapUintptr is not atomic: %v", old))
+ panic(fmt.Sprintf("SwapUintptr is not atomic: %#08x", old))
}
}
}
@@ -827,7 +827,7 @@ func hammerSwapPointer32(uaddr *uint32, count int) {
new := uintptr(seed+i)<<16 | uintptr(seed+i)<<16>>16
old := uintptr(SwapPointer(addr, unsafe.Pointer(new)))
if old>>16 != old<<16>>16 {
- panic(fmt.Sprintf("SwapPointer is not atomic: %v", old))
+ panic(fmt.Sprintf("SwapPointer is not atomic: %#08x", old))
}
}
}
@@ -1463,6 +1463,9 @@ func TestUnaligned64(t *testing.T) {
}
func TestNilDeref(t *testing.T) {
+ if p := runtime.GOOS + "/" + runtime.GOARCH; p == "freebsd/arm" || p == "netbsd/arm" {
+ t.Skipf("issue 7338: skipping test on %q", p)
+ }
funcs := [...]func(){
func() { CompareAndSwapInt32(nil, 0, 0) },
func() { CompareAndSwapInt64(nil, 0, 0) },
diff --git a/src/pkg/sync/atomic/export_linux_arm_test.go b/src/pkg/sync/atomic/export_linux_arm_test.go
index 8c0b5a75c..5cd43353e 100644
--- a/src/pkg/sync/atomic/export_linux_arm_test.go
+++ b/src/pkg/sync/atomic/export_linux_arm_test.go
@@ -4,6 +4,6 @@
package atomic
-func generalCAS64(*uint64, uint64, uint64) bool
+func generalCAS64(addr *uint64, old uint64, new uint64) bool
var GeneralCAS64 = generalCAS64
diff --git a/src/pkg/sync/mutex_test.go b/src/pkg/sync/mutex_test.go
index bf78c6f60..151b25c10 100644
--- a/src/pkg/sync/mutex_test.go
+++ b/src/pkg/sync/mutex_test.go
@@ -9,7 +9,6 @@ package sync_test
import (
"runtime"
. "sync"
- "sync/atomic"
"testing"
)
@@ -90,63 +89,34 @@ func BenchmarkMutexUncontended(b *testing.B) {
Mutex
pad [128]uint8
}
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- for p := 0; p < procs; p++ {
- go func() {
- var mu PaddedMutex
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- mu.Lock()
- mu.Unlock()
- }
- }
- c <- true
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ b.RunParallel(func(pb *testing.PB) {
+ var mu PaddedMutex
+ for pb.Next() {
+ mu.Lock()
+ mu.Unlock()
+ }
+ })
}
func benchmarkMutex(b *testing.B, slack, work bool) {
- const (
- CallsPerSched = 1000
- LocalWork = 100
- GoroutineSlack = 10
- )
- procs := runtime.GOMAXPROCS(-1)
+ var mu Mutex
if slack {
- procs *= GoroutineSlack
+ b.SetParallelism(10)
}
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- var mu Mutex
- for p := 0; p < procs; p++ {
- go func() {
- foo := 0
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- mu.Lock()
- mu.Unlock()
- if work {
- for i := 0; i < LocalWork; i++ {
- foo *= 2
- foo /= 2
- }
- }
+ b.RunParallel(func(pb *testing.PB) {
+ foo := 0
+ for pb.Next() {
+ mu.Lock()
+ mu.Unlock()
+ if work {
+ for i := 0; i < 100; i++ {
+ foo *= 2
+ foo /= 2
}
}
- c <- foo == 42
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ }
+ _ = foo
+ })
}
func BenchmarkMutex(b *testing.B) {
diff --git a/src/pkg/sync/once_test.go b/src/pkg/sync/once_test.go
index 183069a1a..8afda82f3 100644
--- a/src/pkg/sync/once_test.go
+++ b/src/pkg/sync/once_test.go
@@ -5,9 +5,7 @@
package sync_test
import (
- "runtime"
. "sync"
- "sync/atomic"
"testing"
)
@@ -62,24 +60,11 @@ func TestOncePanic(t *testing.T) {
}
func BenchmarkOnce(b *testing.B) {
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
var once Once
f := func() {}
- c := make(chan bool, procs)
- for p := 0; p < procs; p++ {
- go func() {
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- once.Do(f)
- }
- }
- c <- true
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ once.Do(f)
+ }
+ })
}
diff --git a/src/pkg/sync/pool.go b/src/pkg/sync/pool.go
new file mode 100644
index 000000000..1f08707cd
--- /dev/null
+++ b/src/pkg/sync/pool.go
@@ -0,0 +1,223 @@
+// 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 sync
+
+import (
+ "runtime"
+ "sync/atomic"
+ "unsafe"
+)
+
+// A Pool is a set of temporary objects that may be individually saved and
+// retrieved.
+//
+// Any item stored in the Pool may be removed automatically at any time without
+// notification. If the Pool holds the only reference when this happens, the
+// item might be deallocated.
+//
+// A Pool is safe for use by multiple goroutines simultaneously.
+//
+// Pool's purpose is to cache allocated but unused items for later reuse,
+// relieving pressure on the garbage collector. That is, it makes it easy to
+// build efficient, thread-safe free lists. However, it is not suitable for all
+// free lists.
+//
+// An appropriate use of a Pool is to manage a group of temporary items
+// silently shared among and potentially reused by concurrent independent
+// clients of a package. Pool provides a way to amortize allocation overhead
+// across many clients.
+//
+// An example of good use of a Pool is in the fmt package, which maintains a
+// dynamically-sized store of temporary output buffers. The store scales under
+// load (when many goroutines are actively printing) and shrinks when
+// quiescent.
+//
+// On the other hand, a free list maintained as part of a short-lived object is
+// not a suitable use for a Pool, since the overhead does not amortize well in
+// that scenario. It is more efficient to have such objects implement their own
+// free list.
+//
+type Pool struct {
+ local unsafe.Pointer // local fixed-size per-P pool, actual type is [P]poolLocal
+ localSize uintptr // size of the local array
+
+ // New optionally specifies a function to generate
+ // a value when Get would otherwise return nil.
+ // It may not be changed concurrently with calls to Get.
+ New func() interface{}
+}
+
+// Local per-P Pool appendix.
+type poolLocal struct {
+ private interface{} // Can be used only by the respective P.
+ shared []interface{} // Can be used by any P.
+ Mutex // Protects shared.
+ pad [128]byte // Prevents false sharing.
+}
+
+// Put adds x to the pool.
+func (p *Pool) Put(x interface{}) {
+ if raceenabled {
+ // Under race detector the Pool degenerates into no-op.
+ // It's conforming, simple and does not introduce excessive
+ // happens-before edges between unrelated goroutines.
+ return
+ }
+ if x == nil {
+ return
+ }
+ l := p.pin()
+ if l.private == nil {
+ l.private = x
+ x = nil
+ }
+ runtime_procUnpin()
+ if x == nil {
+ return
+ }
+ l.Lock()
+ l.shared = append(l.shared, x)
+ l.Unlock()
+}
+
+// Get selects an arbitrary item from the Pool, removes it from the
+// Pool, and returns it to the caller.
+// Get may choose to ignore the pool and treat it as empty.
+// Callers should not assume any relation between values passed to Put and
+// the values returned by Get.
+//
+// If Get would otherwise return nil and p.New is non-nil, Get returns
+// the result of calling p.New.
+func (p *Pool) Get() interface{} {
+ if raceenabled {
+ if p.New != nil {
+ return p.New()
+ }
+ return nil
+ }
+ l := p.pin()
+ x := l.private
+ l.private = nil
+ runtime_procUnpin()
+ if x != nil {
+ return x
+ }
+ l.Lock()
+ last := len(l.shared) - 1
+ if last >= 0 {
+ x = l.shared[last]
+ l.shared = l.shared[:last]
+ }
+ l.Unlock()
+ if x != nil {
+ return x
+ }
+ return p.getSlow()
+}
+
+func (p *Pool) getSlow() (x interface{}) {
+ // See the comment in pin regarding ordering of the loads.
+ size := atomic.LoadUintptr(&p.localSize) // load-acquire
+ local := p.local // load-consume
+ // Try to steal one element from other procs.
+ pid := runtime_procPin()
+ runtime_procUnpin()
+ for i := 0; i < int(size); i++ {
+ l := indexLocal(local, (pid+i+1)%int(size))
+ l.Lock()
+ last := len(l.shared) - 1
+ if last >= 0 {
+ x = l.shared[last]
+ l.shared = l.shared[:last]
+ l.Unlock()
+ break
+ }
+ l.Unlock()
+ }
+
+ if x == nil && p.New != nil {
+ x = p.New()
+ }
+ return x
+}
+
+// pin pins the current goroutine to P, disables preemption and returns poolLocal pool for the P.
+// Caller must call runtime_procUnpin() when done with the pool.
+func (p *Pool) pin() *poolLocal {
+ pid := runtime_procPin()
+ // In pinSlow we store to localSize and then to local, here we load in opposite order.
+ // Since we've disabled preemption, GC can not happen in between.
+ // Thus here we must observe local at least as large localSize.
+ // We can observe a newer/larger local, it is fine (we must observe its zero-initialized-ness).
+ s := atomic.LoadUintptr(&p.localSize) // load-acquire
+ l := p.local // load-consume
+ if uintptr(pid) < s {
+ return indexLocal(l, pid)
+ }
+ return p.pinSlow()
+}
+
+func (p *Pool) pinSlow() *poolLocal {
+ // Retry under the mutex.
+ // Can not lock the mutex while pinned.
+ runtime_procUnpin()
+ allPoolsMu.Lock()
+ defer allPoolsMu.Unlock()
+ pid := runtime_procPin()
+ // poolCleanup won't be called while we are pinned.
+ s := p.localSize
+ l := p.local
+ if uintptr(pid) < s {
+ return indexLocal(l, pid)
+ }
+ if p.local == nil {
+ allPools = append(allPools, p)
+ }
+ // If GOMAXPROCS changes between GCs, we re-allocate the array and lose the old one.
+ size := runtime.GOMAXPROCS(0)
+ local := make([]poolLocal, size)
+ atomic.StorePointer((*unsafe.Pointer)(&p.local), unsafe.Pointer(&local[0])) // store-release
+ atomic.StoreUintptr(&p.localSize, uintptr(size)) // store-release
+ return &local[pid]
+}
+
+func poolCleanup() {
+ // This function is called with the world stopped, at the beginning of a garbage collection.
+ // It must not allocate and probably should not call any runtime functions.
+ // Defensively zero out everything, 2 reasons:
+ // 1. To prevent false retention of whole Pools.
+ // 2. If GC happens while a goroutine works with l.shared in Put/Get,
+ // it will retain whole Pool. So next cycle memory consumption would be doubled.
+ for i, p := range allPools {
+ allPools[i] = nil
+ for i := 0; i < int(p.localSize); i++ {
+ l := indexLocal(p.local, i)
+ l.private = nil
+ for j := range l.shared {
+ l.shared[j] = nil
+ }
+ l.shared = nil
+ }
+ }
+ allPools = []*Pool{}
+}
+
+var (
+ allPoolsMu Mutex
+ allPools []*Pool
+)
+
+func init() {
+ runtime_registerPoolCleanup(poolCleanup)
+}
+
+func indexLocal(l unsafe.Pointer, i int) *poolLocal {
+ return &(*[1000000]poolLocal)(l)[i]
+}
+
+// Implemented in runtime.
+func runtime_registerPoolCleanup(cleanup func())
+func runtime_procPin() int
+func runtime_procUnpin()
diff --git a/src/pkg/sync/pool_test.go b/src/pkg/sync/pool_test.go
new file mode 100644
index 000000000..509448b62
--- /dev/null
+++ b/src/pkg/sync/pool_test.go
@@ -0,0 +1,151 @@
+// 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.
+
+// Pool is no-op under race detector, so all these tests do not work.
+// +build !race
+
+package sync_test
+
+import (
+ "runtime"
+ "runtime/debug"
+ . "sync"
+ "sync/atomic"
+ "testing"
+ "time"
+)
+
+func TestPool(t *testing.T) {
+ // disable GC so we can control when it happens.
+ defer debug.SetGCPercent(debug.SetGCPercent(-1))
+ var p Pool
+ if p.Get() != nil {
+ t.Fatal("expected empty")
+ }
+ p.Put("a")
+ p.Put("b")
+ if g := p.Get(); g != "a" {
+ t.Fatalf("got %#v; want a", g)
+ }
+ if g := p.Get(); g != "b" {
+ t.Fatalf("got %#v; want b", g)
+ }
+ if g := p.Get(); g != nil {
+ t.Fatalf("got %#v; want nil", g)
+ }
+
+ p.Put("c")
+ debug.SetGCPercent(100) // to allow following GC to actually run
+ runtime.GC()
+ if g := p.Get(); g != nil {
+ t.Fatalf("got %#v; want nil after GC", g)
+ }
+}
+
+func TestPoolNew(t *testing.T) {
+ // disable GC so we can control when it happens.
+ defer debug.SetGCPercent(debug.SetGCPercent(-1))
+
+ i := 0
+ p := Pool{
+ New: func() interface{} {
+ i++
+ return i
+ },
+ }
+ if v := p.Get(); v != 1 {
+ t.Fatalf("got %v; want 1", v)
+ }
+ if v := p.Get(); v != 2 {
+ t.Fatalf("got %v; want 2", v)
+ }
+ p.Put(42)
+ if v := p.Get(); v != 42 {
+ t.Fatalf("got %v; want 42", v)
+ }
+ if v := p.Get(); v != 3 {
+ t.Fatalf("got %v; want 3", v)
+ }
+}
+
+// Test that Pool does not hold pointers to previously cached
+// resources
+func TestPoolGC(t *testing.T) {
+ var p Pool
+ var fin uint32
+ const N = 100
+ for i := 0; i < N; i++ {
+ v := new(string)
+ runtime.SetFinalizer(v, func(vv *string) {
+ atomic.AddUint32(&fin, 1)
+ })
+ p.Put(v)
+ }
+ for i := 0; i < N; i++ {
+ p.Get()
+ }
+ for i := 0; i < 5; i++ {
+ runtime.GC()
+ time.Sleep(time.Duration(i*100+10) * time.Millisecond)
+ // 1 pointer can remain on stack or elsewhere
+ if atomic.LoadUint32(&fin) >= N-1 {
+ return
+ }
+ }
+ t.Fatalf("only %v out of %v resources are finalized",
+ atomic.LoadUint32(&fin), N)
+}
+
+func TestPoolStress(t *testing.T) {
+ const P = 10
+ N := int(1e6)
+ if testing.Short() {
+ N /= 100
+ }
+ var p Pool
+ done := make(chan bool)
+ for i := 0; i < P; i++ {
+ go func() {
+ var v interface{} = 0
+ for j := 0; j < N; j++ {
+ if v == nil {
+ v = 0
+ }
+ p.Put(v)
+ v = p.Get()
+ if v != nil && v.(int) != 0 {
+ t.Fatalf("expect 0, got %v", v)
+ }
+ }
+ done <- true
+ }()
+ }
+ for i := 0; i < P; i++ {
+ <-done
+ }
+}
+
+func BenchmarkPool(b *testing.B) {
+ var p Pool
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ p.Put(1)
+ p.Get()
+ }
+ })
+}
+
+func BenchmarkPoolOverlflow(b *testing.B) {
+ var p Pool
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ for b := 0; b < 100; b++ {
+ p.Put(1)
+ }
+ for b := 0; b < 100; b++ {
+ p.Get()
+ }
+ }
+ })
+}
diff --git a/src/pkg/sync/runtime_sema_test.go b/src/pkg/sync/runtime_sema_test.go
index 57a8dbee7..5b7dd3df3 100644
--- a/src/pkg/sync/runtime_sema_test.go
+++ b/src/pkg/sync/runtime_sema_test.go
@@ -7,7 +7,6 @@ package sync_test
import (
"runtime"
. "sync"
- "sync/atomic"
"testing"
)
@@ -16,72 +15,44 @@ func BenchmarkSemaUncontended(b *testing.B) {
sem uint32
pad [32]uint32
}
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- for p := 0; p < procs; p++ {
- go func() {
- sem := new(PaddedSem)
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- Runtime_Semrelease(&sem.sem)
- Runtime_Semacquire(&sem.sem)
- }
- }
- c <- true
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ b.RunParallel(func(pb *testing.PB) {
+ sem := new(PaddedSem)
+ for pb.Next() {
+ Runtime_Semrelease(&sem.sem)
+ Runtime_Semacquire(&sem.sem)
+ }
+ })
}
func benchmarkSema(b *testing.B, block, work bool) {
- const CallsPerSched = 1000
- const LocalWork = 100
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- c2 := make(chan bool, procs/2)
sem := uint32(0)
if block {
- for p := 0; p < procs/2; p++ {
- go func() {
- Runtime_Semacquire(&sem)
- c2 <- true
- }()
- }
- }
- for p := 0; p < procs; p++ {
+ done := make(chan bool)
go func() {
- foo := 0
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- Runtime_Semrelease(&sem)
- if work {
- for i := 0; i < LocalWork; i++ {
- foo *= 2
- foo /= 2
- }
- }
- Runtime_Semacquire(&sem)
- }
+ for p := 0; p < runtime.GOMAXPROCS(0)/2; p++ {
+ Runtime_Semacquire(&sem)
}
- c <- foo == 42
- Runtime_Semrelease(&sem)
+ done <- true
+ }()
+ defer func() {
+ <-done
}()
}
- if block {
- for p := 0; p < procs/2; p++ {
- <-c2
+ b.RunParallel(func(pb *testing.PB) {
+ foo := 0
+ for pb.Next() {
+ Runtime_Semrelease(&sem)
+ if work {
+ for i := 0; i < 100; i++ {
+ foo *= 2
+ foo /= 2
+ }
+ }
+ Runtime_Semacquire(&sem)
}
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ _ = foo
+ Runtime_Semrelease(&sem)
+ })
}
func BenchmarkSemaSyntNonblock(b *testing.B) {
diff --git a/src/pkg/sync/rwmutex_test.go b/src/pkg/sync/rwmutex_test.go
index 39d5d6540..0436f9723 100644
--- a/src/pkg/sync/rwmutex_test.go
+++ b/src/pkg/sync/rwmutex_test.go
@@ -160,64 +160,39 @@ func BenchmarkRWMutexUncontended(b *testing.B) {
RWMutex
pad [32]uint32
}
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- for p := 0; p < procs; p++ {
- go func() {
- var rwm PaddedRWMutex
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- rwm.RLock()
- rwm.RLock()
- rwm.RUnlock()
- rwm.RUnlock()
- rwm.Lock()
- rwm.Unlock()
- }
- }
- c <- true
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ b.RunParallel(func(pb *testing.PB) {
+ var rwm PaddedRWMutex
+ for pb.Next() {
+ rwm.RLock()
+ rwm.RLock()
+ rwm.RUnlock()
+ rwm.RUnlock()
+ rwm.Lock()
+ rwm.Unlock()
+ }
+ })
}
func benchmarkRWMutex(b *testing.B, localWork, writeRatio int) {
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
var rwm RWMutex
- for p := 0; p < procs; p++ {
- go func() {
- foo := 0
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- foo++
- if foo%writeRatio == 0 {
- rwm.Lock()
- rwm.Unlock()
- } else {
- rwm.RLock()
- for i := 0; i != localWork; i += 1 {
- foo *= 2
- foo /= 2
- }
- rwm.RUnlock()
- }
+ b.RunParallel(func(pb *testing.PB) {
+ foo := 0
+ for pb.Next() {
+ foo++
+ if foo%writeRatio == 0 {
+ rwm.Lock()
+ rwm.Unlock()
+ } else {
+ rwm.RLock()
+ for i := 0; i != localWork; i += 1 {
+ foo *= 2
+ foo /= 2
}
+ rwm.RUnlock()
}
- c <- foo == 42
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ }
+ _ = foo
+ })
}
func BenchmarkRWMutexWrite100(b *testing.B) {
diff --git a/src/pkg/sync/waitgroup.go b/src/pkg/sync/waitgroup.go
index 22681115c..4c64dca39 100644
--- a/src/pkg/sync/waitgroup.go
+++ b/src/pkg/sync/waitgroup.go
@@ -67,11 +67,13 @@ func (wg *WaitGroup) Add(delta int) {
return
}
wg.m.Lock()
- for i := int32(0); i < wg.waiters; i++ {
- runtime_Semrelease(wg.sema)
+ if atomic.LoadInt32(&wg.counter) == 0 {
+ for i := int32(0); i < wg.waiters; i++ {
+ runtime_Semrelease(wg.sema)
+ }
+ wg.waiters = 0
+ wg.sema = nil
}
- wg.waiters = 0
- wg.sema = nil
wg.m.Unlock()
}
diff --git a/src/pkg/sync/waitgroup_test.go b/src/pkg/sync/waitgroup_test.go
index 84c4cfc37..4c0a043c0 100644
--- a/src/pkg/sync/waitgroup_test.go
+++ b/src/pkg/sync/waitgroup_test.go
@@ -5,7 +5,6 @@
package sync_test
import (
- "runtime"
. "sync"
"sync/atomic"
"testing"
@@ -61,60 +60,60 @@ func TestWaitGroupMisuse(t *testing.T) {
t.Fatal("Should panic")
}
+func TestWaitGroupRace(t *testing.T) {
+ // Run this test for about 1ms.
+ for i := 0; i < 1000; i++ {
+ wg := &WaitGroup{}
+ n := new(int32)
+ // spawn goroutine 1
+ wg.Add(1)
+ go func() {
+ atomic.AddInt32(n, 1)
+ wg.Done()
+ }()
+ // spawn goroutine 2
+ wg.Add(1)
+ go func() {
+ atomic.AddInt32(n, 1)
+ wg.Done()
+ }()
+ // Wait for goroutine 1 and 2
+ wg.Wait()
+ if atomic.LoadInt32(n) != 2 {
+ t.Fatal("Spurious wakeup from Wait")
+ }
+ }
+}
+
func BenchmarkWaitGroupUncontended(b *testing.B) {
type PaddedWaitGroup struct {
WaitGroup
pad [128]uint8
}
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
- for p := 0; p < procs; p++ {
- go func() {
- var wg PaddedWaitGroup
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- wg.Add(1)
- wg.Done()
- wg.Wait()
- }
- }
- c <- true
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ b.RunParallel(func(pb *testing.PB) {
+ var wg PaddedWaitGroup
+ for pb.Next() {
+ wg.Add(1)
+ wg.Done()
+ wg.Wait()
+ }
+ })
}
func benchmarkWaitGroupAddDone(b *testing.B, localWork int) {
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
var wg WaitGroup
- for p := 0; p < procs; p++ {
- go func() {
- foo := 0
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- wg.Add(1)
- for i := 0; i < localWork; i++ {
- foo *= 2
- foo /= 2
- }
- wg.Done()
- }
+ b.RunParallel(func(pb *testing.PB) {
+ foo := 0
+ for pb.Next() {
+ wg.Add(1)
+ for i := 0; i < localWork; i++ {
+ foo *= 2
+ foo /= 2
}
- c <- foo == 42
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ wg.Done()
+ }
+ _ = foo
+ })
}
func BenchmarkWaitGroupAddDone(b *testing.B) {
@@ -126,34 +125,18 @@ func BenchmarkWaitGroupAddDoneWork(b *testing.B) {
}
func benchmarkWaitGroupWait(b *testing.B, localWork int) {
- const CallsPerSched = 1000
- procs := runtime.GOMAXPROCS(-1)
- N := int32(b.N / CallsPerSched)
- c := make(chan bool, procs)
var wg WaitGroup
- wg.Add(procs)
- for p := 0; p < procs; p++ {
- go wg.Done()
- }
- for p := 0; p < procs; p++ {
- go func() {
- foo := 0
- for atomic.AddInt32(&N, -1) >= 0 {
- runtime.Gosched()
- for g := 0; g < CallsPerSched; g++ {
- wg.Wait()
- for i := 0; i < localWork; i++ {
- foo *= 2
- foo /= 2
- }
- }
+ b.RunParallel(func(pb *testing.PB) {
+ foo := 0
+ for pb.Next() {
+ wg.Wait()
+ for i := 0; i < localWork; i++ {
+ foo *= 2
+ foo /= 2
}
- c <- foo == 42
- }()
- }
- for p := 0; p < procs; p++ {
- <-c
- }
+ }
+ _ = foo
+ })
}
func BenchmarkWaitGroupWait(b *testing.B) {
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 02:28:43 +0000