From e73db1d7d226408976ed89d514588a5fee7e87fa Mon Sep 17 00:00:00 2001
From: Andy Pan <panjf2000@gmail.com>
Date: Fri, 27 Sep 2019 20:51:46 +0800
Subject: [PATCH] Replace mutex with spin-lock

---
 pool.go      |  6 ++++--
 pool_func.go |  6 ++++--
 spinlock.go  | 27 +++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 4 deletions(-)
 create mode 100644 spinlock.go

diff --git a/pool.go b/pool.go
index 75741de1..9af46dec 100644
--- a/pool.go
+++ b/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()
diff --git a/pool_func.go b/pool_func.go
index 8ffe3add..59d3187d 100644
--- a/pool_func.go
+++ b/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()
diff --git a/spinlock.go b/spinlock.go
new file mode 100644
index 00000000..3b87c875
--- /dev/null
+++ b/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)
+}