update

ants.go

@@ -25,6 +25,7 @@ package ants
 import (
 	"errors"
 	"math"
+	"runtime"
 )
 
 const (
@@ -68,3 +69,10 @@ var (
 	ErrPoolSizeInvalid = errors.New("invalid size for pool")
 	ErrPoolClosed      = errors.New("this pool has been closed")
 )
+
+var workerArgsCap = func() int {
+	if runtime.GOMAXPROCS(0) == 1 {
+		return 0
+	}
+	return 1
+}()

pool.go

@@ -177,20 +177,19 @@ func (p *Pool) getWorker() *Worker {
 		if wp == nil {
 			w = &Worker{
 				pool: p,
-				task: make(chan f),
+				task: make(chan f, workerArgsCap),
 			}
-			w.run()
-			atomic.AddInt32(&p.running, 1)
 		} else {
 			w = wp.(*Worker)
 		}
+		w.run()
+		p.workerPool.Put(w)
 	}
 	return w
 }
 
 // putWorker puts a worker back into free pool, recycling the goroutines.
 func (p *Pool) putWorker(worker *Worker) {
-	p.workerPool.Put(worker)
 	p.lock.Lock()
 	p.workers = append(p.workers, worker)
 	p.lock.Unlock()

pool_func.go

@@ -178,20 +178,19 @@ func (p *PoolWithFunc) getWorker() *WorkerWithFunc {
 		if wp == nil {
 			w = &WorkerWithFunc{
 				pool: p,
-				args: make(chan interface{}),
+				args: make(chan interface{}, workerArgsCap),
 			}
-			w.run()
-			atomic.AddInt32(&p.running, 1)
 		} else {
 			w = wp.(*WorkerWithFunc)
 		}
+		w.run()
+		p.workerPool.Put(w)
 	}
 	return w
 }
 
 // putWorker puts a worker back into free pool, recycling the goroutines.
 func (p *PoolWithFunc) putWorker(worker *WorkerWithFunc) {
-	p.workerPool.Put(worker)
 	p.lock.Lock()
 	p.workers = append(p.workers, worker)
 	p.lock.Unlock()

worker.go

@@ -40,6 +40,7 @@ type Worker struct {
 // run will start a goroutine to repeat the process
 // that perform the function calls.
 func (w *Worker) run() {
+	atomic.AddInt32(&w.pool.running, 1)
 	go func() {
 		for f := range w.task {
 			if f == nil {

worker_func.go

@@ -40,6 +40,7 @@ type WorkerWithFunc struct {
 // run will start a goroutine to repeat the process
 // that perform the function calls.
 func (w *WorkerWithFunc) run() {
+	atomic.AddInt32(&w.pool.running, 1)
 	go func() {
 		for args := range w.args {
 			if args == nil {