Replace mutex with spin-lock

pool.go

@@ -46,7 +46,7 @@ type Pool struct {
 	release int32
 
 	// lock for synchronous operation.
-	lock sync.Mutex
+	lock sync.Locker
 
 	// cond for waiting to get a idle worker.
 	cond *sync.Cond
@@ -146,6 +146,7 @@ func NewPool(size int, options ...Option) (*Pool, error) {
 			nonblocking:      opts.Nonblocking,
 			maxBlockingTasks: int32(opts.MaxBlockingTasks),
 			panicHandler:     opts.PanicHandler,
+			lock:             SpinLock(),
 		}
 	} else {
 		p = &Pool{
@@ -154,9 +155,10 @@ func NewPool(size int, options ...Option) (*Pool, error) {
 			nonblocking:      opts.Nonblocking,
 			maxBlockingTasks: int32(opts.MaxBlockingTasks),
 			panicHandler:     opts.PanicHandler,
+			lock:             SpinLock(),
 		}
 	}
-	p.cond = sync.NewCond(&p.lock)
+	p.cond = sync.NewCond(p.lock)
 
 	// Start a goroutine to clean up expired workers periodically.
 	go p.periodicallyPurge()

pool_func.go

@@ -46,7 +46,7 @@ type PoolWithFunc struct {
 	release int32
 
 	// lock for synchronous operation.
-	lock sync.Mutex
+	lock sync.Locker
 
 	// cond for waiting to get a idle worker.
 	cond *sync.Cond
@@ -154,6 +154,7 @@ func NewPoolWithFunc(size int, pf func(interface{}), options ...Option) (*PoolWi
 			nonblocking:      opts.Nonblocking,
 			maxBlockingTasks: int32(opts.MaxBlockingTasks),
 			panicHandler:     opts.PanicHandler,
+			lock:             SpinLock(),
 		}
 	} else {
 		p = &PoolWithFunc{
@@ -163,9 +164,10 @@ func NewPoolWithFunc(size int, pf func(interface{}), options ...Option) (*PoolWi
 			nonblocking:      opts.Nonblocking,
 			maxBlockingTasks: int32(opts.MaxBlockingTasks),
 			panicHandler:     opts.PanicHandler,
+			lock:             SpinLock(),
 		}
 	}
-	p.cond = sync.NewCond(&p.lock)
+	p.cond = sync.NewCond(p.lock)
 
 	// Start a goroutine to clean up expired workers periodically.
 	go p.periodicallyPurge()

spinlock.go

@@ -0,0 +1,27 @@
+// Copyright 2019 Andy Pan. All rights reserved.
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+package ants
+
+import (
+	"runtime"
+	"sync"
+	"sync/atomic"
+)
+
+type spinLock uint32
+
+func (sl *spinLock) Lock() {
+	for !atomic.CompareAndSwapUint32((*uint32)(sl), 0, 1) {
+		runtime.Gosched()
+	}
+}
+
+func (sl *spinLock) Unlock() {
+	atomic.StoreUint32((*uint32)(sl), 0)
+}
+
+func SpinLock() sync.Locker {
+	return new(spinLock)
+}