diff --git a/ants_benchmark_test.go b/ants_benchmark_test.go
index 698c5d4..0d6e0c6 100644
--- a/ants_benchmark_test.go
+++ b/ants_benchmark_test.go
@@ -72,7 +72,6 @@ func BenchmarkGoroutineWithFunc(b *testing.B) {
 		}
 		wg.Wait()
 	}
-	//b.Logf("total memory usage:%d MB", mem.TotalAlloc/MiB)
 }
 
 func BenchmarkAntsPoolWithFunc(b *testing.B) {
@@ -88,9 +87,8 @@ func BenchmarkAntsPoolWithFunc(b *testing.B) {
 			p.Serve(loop)
 		}
 		wg.Wait()
-		//b.Logf("running goroutines: %d", p.Running())
+		b.Logf("running goroutines: %d", p.Running())
 	}
-	//b.Logf("total memory usage:%d MB", mem.TotalAlloc/MiB)
 }
 
 func BenchmarkGoroutine(b *testing.B) {
@@ -100,15 +98,14 @@ func BenchmarkGoroutine(b *testing.B) {
 		}
 	}
 
-	//b.Logf("total memory usage:%d MB", mem.TotalAlloc/MiB)
 }
 
 func BenchmarkAntsPool(b *testing.B) {
+	b.N = 3
 	for i := 0; i < b.N; i++ {
 		for j := 0; j < RunTimes; j++ {
 			ants.Push(demoFunc)
 		}
 		b.Logf("running goroutines: %d", ants.Running())
 	}
-	//b.Logf("total memory usage:%d MB", mem.TotalAlloc/MiB)
 }
diff --git a/examples/main.go b/examples/main.go
index 5f71174..719c6b5 100644
--- a/examples/main.go
+++ b/examples/main.go
@@ -69,5 +69,6 @@ func main() {
 		p.Serve(str)
 	}
 	wg.Wait()
+	fmt.Printf("running goroutines: %d\n", p.Running())
 	fmt.Println("finish all tasks!")
 }
diff --git a/pool_func.go b/pool_func.go
index 0e888e5..6ea84fb 100644
--- a/pool_func.go
+++ b/pool_func.go
@@ -26,7 +26,6 @@ import (
 	"math"
 	"sync"
 	"sync/atomic"
-	"time"
 )
 
 type pf func(interface{}) error
@@ -55,10 +54,10 @@ type PoolWithFunc struct {
 
 	lock sync.Mutex
 
-	// closed is used to confirm whether this pool has been closed.
-	closed int32
-
 	poolFunc pf
+
+	once sync.Once
+
 }
 
 // NewPoolWithFunc generates a instance of ants pool with a specific function.
@@ -69,8 +68,7 @@ func NewPoolWithFunc(size int, f pf) (*PoolWithFunc, error) {
 	p := &PoolWithFunc{
 		capacity:   int32(size),
 		freeSignal: make(chan sig, math.MaxInt32),
-		release:    make(chan sig),
-		closed:     0,
+		release:    make(chan sig, 1),
 		poolFunc:   f,
 	}
 
@@ -79,27 +77,12 @@ func NewPoolWithFunc(size int, f pf) (*PoolWithFunc, error) {
 
 //-------------------------------------------------------------------------
 
-// scanAndClean is a goroutine who will periodically clean up
-// after it is noticed that this pool is closed.
-func (p *PoolWithFunc) scanAndClean() {
-	ticker := time.NewTicker(DefaultCleanIntervalTime * time.Second)
-	go func() {
-		ticker.Stop()
-		for range ticker.C {
-			if atomic.LoadInt32(&p.closed) == 1 {
-				p.lock.Lock()
-				for _, w := range p.workers {
-					w.stop()
-				}
-				p.lock.Unlock()
-			}
-		}
-	}()
-}
-
 // Serve submit a task to pool
 func (p *PoolWithFunc) Serve(args interface{}) error {
-	if atomic.LoadInt32(&p.closed) == 1 {
+	//if atomic.LoadInt32(&p.closed) == 1 {
+	//	return ErrPoolClosed
+	//}
+	if len(p.release) > 0 {
 		return ErrPoolClosed
 	}
 	w := p.getWorker()
@@ -124,10 +107,9 @@ func (p *PoolWithFunc) Cap() int {
 
 // Release Closed this pool
 func (p *PoolWithFunc) Release() error {
-	p.lock.Lock()
-	atomic.StoreInt32(&p.closed, 1)
-	close(p.release)
-	p.lock.Unlock()
+	p.once.Do(func() {
+		p.release<- sig{}
+	})
 	return nil
 }
 
diff --git a/worker_func.go b/worker_func.go
index 87dd6a4..9580b79 100644
--- a/worker_func.go
+++ b/worker_func.go
@@ -43,7 +43,7 @@ func (w *WorkerWithFunc) run() {
 	atomic.AddInt32(&w.pool.running, 1)
 	go func() {
 		for args := range w.args {
-			if args == nil {
+			if args == nil || len(w.pool.release) > 0 {
 				atomic.AddInt32(&w.pool.running, -1)
 				return
 			}
@@ -53,6 +53,26 @@ func (w *WorkerWithFunc) run() {
 	}()
 }
 
+//func (w *WorkerWithFunc) run() {
+//	atomic.AddInt32(&w.pool.running, 1)
+//	go func() {
+//		for {
+//			select {
+//			case args := <-w.args:
+//				if args == nil {
+//					atomic.AddInt32(&w.pool.running, -1)
+//					return
+//				}
+//				w.pool.poolFunc(args)
+//				w.pool.putWorker(w)
+//			case <-w.pool.release:
+//				atomic.AddInt32(&w.pool.running, -1)
+//				return
+//			}
+//		}
+//	}()
+//}
+
 // stop this worker.
 func (w *WorkerWithFunc) stop() {
 	w.args <- nil