diff --git a/ants.go b/ants.go
index de5494d..8096d06 100644
--- a/ants.go
+++ b/ants.go
@@ -19,9 +19,14 @@
 
 package ants
 
-const DEFAULT_POOL_SIZE = 50000
+import "github.com/iris-contrib/errors"
 
-var defaultPool = NewPool(DEFAULT_POOL_SIZE)
+const (
+	DEFAULT_POOL_SIZE           = 50000
+	DEFAULT_CLEAN_INTERVAL_TIME = 30
+)
+
+var defaultPool, _ = NewPool(DEFAULT_POOL_SIZE)
 
 func Push(task f) error {
 	return defaultPool.Push(task)
@@ -38,3 +43,12 @@ func Cap() int {
 func Free() int {
 	return defaultPool.Free()
 }
+
+func Release() {
+
+}
+
+var (
+	PoolSizeInvalidError = errors.New("invalid size for pool")
+	PoolClosedError      = errors.New("this pool has been closed")
+)
diff --git a/ants_benchmark_test.go b/ants_benchmark_test.go
index 5ce9e2b..f6a1bdc 100644
--- a/ants_benchmark_test.go
+++ b/ants_benchmark_test.go
@@ -6,7 +6,7 @@ import (
 	"sync"
 )
 
-const RunTimes = 1000000
+const RunTimes = 10000000
 
 func BenchmarkGoroutine(b *testing.B) {
 	for i := 0; i < b.N; i++ {
@@ -43,4 +43,3 @@ func BenchmarkPoolGroutine(b *testing.B) {
 //		p.Push(demoFunc)
 //	}
 //}
-
diff --git a/ants_test.go b/ants_test.go
index e349a6d..5a1b696 100644
--- a/ants_test.go
+++ b/ants_test.go
@@ -4,8 +4,8 @@ import (
 	"testing"
 	"github.com/panjf2000/ants"
 	"sync"
-	"time"
 	"runtime"
+	"time"
 )
 
 var n = 1000000
@@ -27,6 +27,8 @@ var n = 1000000
 
 func forSleep() {
 	time.Sleep(time.Millisecond)
+	//for i := 0; i < 10000; i++ {
+	//}
 }
 
 func TestNoPool(t *testing.T) {
@@ -68,7 +70,7 @@ func TestDefaultPool(t *testing.T) {
 }
 
 func TestCustomPool(t *testing.T) {
-	p := ants.NewPool(30000)
+	p, _ := ants.NewPool(30000)
 	var wg sync.WaitGroup
 	for i := 0; i < n; i++ {
 		wg.Add(1)
diff --git a/examples/main.go b/examples/main.go
new file mode 100644
index 0000000..61a2c67
--- /dev/null
+++ b/examples/main.go
@@ -0,0 +1,31 @@
+package main
+
+import (
+	"fmt"
+	"github.com/panjf2000/ants"
+	"sync"
+)
+
+func myFunc() {
+	fmt.Println("Hello World!")
+}
+
+func main() {
+	//
+	runTimes := 10000
+
+	// set 100 the size of goroutine pool
+	p, _ := ants.NewPool(100)
+
+	var wg sync.WaitGroup
+	// submit
+	for i := 0; i < runTimes; i++ {
+		wg.Add(1)
+		p.Push(func() {
+			myFunc()
+			wg.Done()
+		})
+	}
+	wg.Wait()
+	fmt.Println("finish all tasks!")
+}
diff --git a/pool.go b/pool.go
index 3e63551..eedbd23 100644
--- a/pool.go
+++ b/pool.go
@@ -19,10 +19,10 @@
 package ants
 
 import (
-	"runtime"
 	"sync/atomic"
 	"sync"
 	"math"
+	"time"
 )
 
 type sig struct{}
@@ -35,25 +35,46 @@ type Pool struct {
 	freeSignal chan sig
 	workers    []*Worker
 	workerPool sync.Pool
-	destroy    chan sig
+	release    chan sig
 	lock       sync.Mutex
+	closed     int32
 }
 
-func NewPool(size int) *Pool {
+func NewPool(size int) (*Pool, error) {
+	if size <= 0 {
+		return nil, PoolSizeInvalidError
+	}
 	p := &Pool{
 		capacity:   int32(size),
 		freeSignal: make(chan sig, math.MaxInt32),
-		destroy:    make(chan sig, runtime.GOMAXPROCS(-1)),
+		release:    make(chan sig),
+		closed:     0,
 	}
 
-	return p
+	return p, nil
 }
 
 //-------------------------------------------------------------------------
 
+func (p *Pool) scanAndClean() {
+	ticker := time.NewTicker(DEFAULT_CLEAN_INTERVAL_TIME * 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()
+			}
+		}
+	}()
+}
+
 func (p *Pool) Push(task f) error {
-	if len(p.destroy) > 0 {
-		return nil
+	if atomic.LoadInt32(&p.closed) == 1 {
+		return PoolClosedError
 	}
 	w := p.getWorker()
 	w.sendTask(task)
@@ -72,15 +93,18 @@ func (p *Pool) Cap() int {
 	return int(atomic.LoadInt32(&p.capacity))
 }
 
-func (p *Pool) Destroy() error {
+func (p *Pool) Release() error {
 	p.lock.Lock()
-	defer p.lock.Unlock()
-	for i := 0; i < runtime.GOMAXPROCS(-1)+1; i++ {
-		p.destroy <- sig{}
-	}
+	atomic.StoreInt32(&p.closed, 1)
+	close(p.release)
+	p.lock.Unlock()
 	return nil
 }
 
+func (p *Pool) ReSize(size int) {
+	atomic.StoreInt32(&p.capacity, int32(size))
+}
+
 //-------------------------------------------------------------------------
 
 func (p *Pool) getWorker() *Worker {