update

pool.go

@@ -56,6 +56,8 @@ type Pool struct {
 
 	once sync.Once
 
+	cachePool sync.Pool
+
 	// PanicHandler is used to handle panics from each worker goroutine.
 	// if nil, panics will be thrown out again from worker goroutines.
 	PanicHandler func(interface{})
@@ -185,7 +187,7 @@ func (p *Pool) decRunning() {
 // getWorker returns a available worker to run the tasks.
 func (p *Pool) getWorker() *Worker {
 	var w *Worker
-	waiting := false
+	var waiting bool
 
 	p.lock.Lock()
 	defer p.lock.Unlock()
@@ -193,7 +195,13 @@ func (p *Pool) getWorker() *Worker {
 	idleWorkers := p.workers
 	n := len(idleWorkers) - 1
 	if n < 0 {
-		waiting = p.Running() >= p.Cap()
+		if p.Running() >= p.Cap() {
+			waiting = true
+		} else {
+			if cacheWorker := p.cachePool.Get(); cacheWorker != nil {
+				return cacheWorker.(*Worker)
+			}
+		}
 	} else {
 		w = idleWorkers[n]
 		idleWorkers[n] = nil

pool_func.go

@@ -59,6 +59,8 @@ type PoolWithFunc struct {
 
 	once sync.Once
 
+	cachePool sync.Pool
+
 	// PanicHandler is used to handle panics from each worker goroutine.
 	// if nil, panics will be thrown out again from worker goroutines.
 	PanicHandler func(interface{})
@@ -198,6 +200,13 @@ func (p *PoolWithFunc) getWorker() *WorkerWithFunc {
 	n := len(idleWorkers) - 1
 	if n < 0 {
 		waiting = p.Running() >= p.Cap()
+		if p.Running() >= p.Cap() {
+			waiting = true
+		} else {
+			if cacheWorker := p.cachePool.Get(); cacheWorker != nil {
+				return cacheWorker.(*WorkerWithFunc)
+			}
+		}
 	} else {
 		w = idleWorkers[n]
 		idleWorkers[n] = nil

worker.go

@@ -54,14 +54,15 @@ func (w *Worker) run() {
 				}
 			}
 		}()
-		
+
 		for f := range w.task {
 			if f == nil {
 				w.pool.decRunning()
+				w.pool.cachePool.Put(w)
 				return
 			}
 			f()
 			w.pool.putWorker(w)
 		}
 	}()
-}
+}

worker_func.go

@@ -54,14 +54,15 @@ func (w *WorkerWithFunc) run() {
 				}
 			}
 		}()
-		
+
 		for args := range w.args {
 			if args == nil {
 				w.pool.decRunning()
+				w.pool.cachePool.Put(w)
 				return
 			}
 			w.pool.poolFunc(args)
 			w.pool.putWorker(w)
 		}
 	}()
-}
+}