diff --git a/docs/cmd/hrp.md b/docs/cmd/hrp.md
index a8884d6b..61da5cfd 100644
--- a/docs/cmd/hrp.md
+++ b/docs/cmd/hrp.md
@@ -22,4 +22,4 @@ Copyright 2021 debugtalk
 * [hrp har2case](hrp_har2case.md)	 - Convert HAR to json/yaml testcase files
 * [hrp run](hrp_run.md)	 - run API test
 
-###### Auto generated by spf13/cobra on 23-Dec-2021
+###### Auto generated by spf13/cobra on 24-Dec-2021
diff --git a/docs/cmd/hrp_boom.md b/docs/cmd/hrp_boom.md
index f61e625c..c5a65c42 100644
--- a/docs/cmd/hrp_boom.md
+++ b/docs/cmd/hrp_boom.md
@@ -38,4 +38,4 @@ hrp boom [flags]
 
 * [hrp](hrp.md)	 - One-stop solution for HTTP(S) testing.
 
-###### Auto generated by spf13/cobra on 23-Dec-2021
+###### Auto generated by spf13/cobra on 24-Dec-2021
diff --git a/docs/cmd/hrp_har2case.md b/docs/cmd/hrp_har2case.md
index 30afecc9..8e559e4b 100644
--- a/docs/cmd/hrp_har2case.md
+++ b/docs/cmd/hrp_har2case.md
@@ -23,4 +23,4 @@ hrp har2case harPath... [flags]
 
 * [hrp](hrp.md)	 - One-stop solution for HTTP(S) testing.
 
-###### Auto generated by spf13/cobra on 23-Dec-2021
+###### Auto generated by spf13/cobra on 24-Dec-2021
diff --git a/docs/cmd/hrp_run.md b/docs/cmd/hrp_run.md
index 26f75e9d..96cd3590 100644
--- a/docs/cmd/hrp_run.md
+++ b/docs/cmd/hrp_run.md
@@ -31,4 +31,4 @@ hrp run path... [flags]
 
 * [hrp](hrp.md)	 - One-stop solution for HTTP(S) testing.
 
-###### Auto generated by spf13/cobra on 23-Dec-2021
+###### Auto generated by spf13/cobra on 24-Dec-2021
diff --git a/internal/boomer/boomer.go b/internal/boomer/boomer.go
index a0c59b2a..55a01e7f 100644
--- a/internal/boomer/boomer.go
+++ b/internal/boomer/boomer.go
@@ -9,26 +9,19 @@ import (
 
 // A Boomer is used to run tasks.
 type Boomer struct {
-	rateLimiter RateLimiter
-
 	localRunner *localRunner
-	spawnCount  int
-	spawnRate   float64
 
 	cpuProfile         string
 	cpuProfileDuration time.Duration
 
 	memoryProfile         string
 	memoryProfileDuration time.Duration
-
-	outputs []Output
 }
 
 // NewStandaloneBoomer returns a new Boomer, which can run without master.
 func NewStandaloneBoomer(spawnCount int, spawnRate float64) *Boomer {
 	return &Boomer{
-		spawnCount: spawnCount,
-		spawnRate:  spawnRate,
+		localRunner: newLocalRunner(spawnCount, spawnRate),
 	}
 }
 
@@ -52,12 +45,16 @@ func (b *Boomer) SetRateLimiter(maxRPS int64, requestIncreaseRate string) {
 		log.Error().Err(err).Msg("failed to create rate limiter")
 		return
 	}
-	b.rateLimiter = rateLimiter
+
+	if rateLimiter != nil {
+		b.localRunner.rateLimitEnabled = true
+		b.localRunner.rateLimiter = rateLimiter
+	}
 }
 
 // AddOutput accepts outputs which implements the boomer.Output interface.
 func (b *Boomer) AddOutput(o Output) {
-	b.outputs = append(b.outputs, o)
+	b.localRunner.addOutput(o)
 }
 
 // EnableCPUProfile will start cpu profiling after run.
@@ -87,19 +84,12 @@ func (b *Boomer) Run(tasks ...*Task) {
 		}
 	}
 
-	b.localRunner = newLocalRunner(tasks, b.rateLimiter, b.spawnCount, b.spawnRate)
-	for _, o := range b.outputs {
-		b.localRunner.addOutput(o)
-	}
+	b.localRunner.setTasks(tasks)
 	b.localRunner.start()
 }
 
 // RecordTransaction reports a transaction stat.
 func (b *Boomer) RecordTransaction(name string, success bool, elapsedTime int64, contentSize int64) {
-	if b.localRunner == nil {
-		log.Warn().Msg("boomer not initialized")
-		return
-	}
 	b.localRunner.stats.transactionChan <- &transaction{
 		name:        name,
 		success:     success,
@@ -110,10 +100,6 @@ func (b *Boomer) RecordTransaction(name string, success bool, elapsedTime int64,
 
 // RecordSuccess reports a success.
 func (b *Boomer) RecordSuccess(requestType, name string, responseTime int64, responseLength int64) {
-	if b.localRunner == nil {
-		log.Warn().Msg("boomer not initialized")
-		return
-	}
 	b.localRunner.stats.requestSuccessChan <- &requestSuccess{
 		requestType:    requestType,
 		name:           name,
@@ -124,10 +110,6 @@ func (b *Boomer) RecordSuccess(requestType, name string, responseTime int64, res
 
 // RecordFailure reports a failure.
 func (b *Boomer) RecordFailure(requestType, name string, responseTime int64, exception string) {
-	if b.localRunner == nil {
-		log.Warn().Msg("boomer not initialized")
-		return
-	}
 	b.localRunner.stats.requestFailureChan <- &requestFailure{
 		requestType:  requestType,
 		name:         name,
@@ -138,9 +120,5 @@ func (b *Boomer) RecordFailure(requestType, name string, responseTime int64, exc
 
 // Quit will send a quit message to the master.
 func (b *Boomer) Quit() {
-	if b.localRunner == nil {
-		log.Warn().Msg("boomer not initialized")
-		return
-	}
 	b.localRunner.stop()
 }
diff --git a/internal/boomer/boomer_test.go b/internal/boomer/boomer_test.go
index 384ecbd4..7f113f87 100644
--- a/internal/boomer/boomer_test.go
+++ b/internal/boomer/boomer_test.go
@@ -12,11 +12,11 @@ import (
 func TestNewStandaloneBoomer(t *testing.T) {
 	b := NewStandaloneBoomer(100, 10)
 
-	if b.spawnCount != 100 {
+	if b.localRunner.spawnCount != 100 {
 		t.Error("spawnCount should be 100")
 	}
 
-	if b.spawnRate != 10 {
+	if b.localRunner.spawnRate != 10 {
 		t.Error("spawnRate should be 10")
 	}
 }
@@ -25,7 +25,7 @@ func TestSetRateLimiter(t *testing.T) {
 	b := NewStandaloneBoomer(100, 10)
 	b.SetRateLimiter(10, "10/1s")
 
-	if b.rateLimiter == nil {
+	if b.localRunner.rateLimiter == nil {
 		t.Error("b.rateLimiter should not be nil")
 	}
 }
@@ -35,7 +35,7 @@ func TestAddOutput(t *testing.T) {
 	b.AddOutput(NewConsoleOutput())
 	b.AddOutput(NewConsoleOutput())
 
-	if len(b.outputs) != 2 {
+	if len(b.localRunner.outputs) != 2 {
 		t.Error("length of outputs should be 2")
 	}
 }
@@ -106,7 +106,7 @@ func TestCreateRatelimiter(t *testing.T) {
 	b := NewStandaloneBoomer(10, 10)
 	b.SetRateLimiter(100, "-1")
 
-	if stableRateLimiter, ok := b.rateLimiter.(*StableRateLimiter); !ok {
+	if stableRateLimiter, ok := b.localRunner.rateLimiter.(*StableRateLimiter); !ok {
 		t.Error("Expected stableRateLimiter")
 	} else {
 		if stableRateLimiter.threshold != 100 {
@@ -115,7 +115,7 @@ func TestCreateRatelimiter(t *testing.T) {
 	}
 
 	b.SetRateLimiter(0, "1")
-	if rampUpRateLimiter, ok := b.rateLimiter.(*RampUpRateLimiter); !ok {
+	if rampUpRateLimiter, ok := b.localRunner.rateLimiter.(*RampUpRateLimiter); !ok {
 		t.Error("Expected rampUpRateLimiter")
 	} else {
 		if rampUpRateLimiter.maxThreshold != math.MaxInt64 {
@@ -127,7 +127,7 @@ func TestCreateRatelimiter(t *testing.T) {
 	}
 
 	b.SetRateLimiter(10, "2/2s")
-	if rampUpRateLimiter, ok := b.rateLimiter.(*RampUpRateLimiter); !ok {
+	if rampUpRateLimiter, ok := b.localRunner.rateLimiter.(*RampUpRateLimiter); !ok {
 		t.Error("Expected rampUpRateLimiter")
 	} else {
 		if rampUpRateLimiter.maxThreshold != 10 {
diff --git a/internal/boomer/runner.go b/internal/boomer/runner.go
index 4d7f56b8..1a6f3c81 100644
--- a/internal/boomer/runner.go
+++ b/internal/boomer/runner.go
@@ -201,20 +201,17 @@ type localRunner struct {
 	stopChan chan bool
 }
 
-func newLocalRunner(tasks []*Task, rateLimiter RateLimiter, spawnCount int, spawnRate float64) (r *localRunner) {
-	r = &localRunner{}
-	r.setTasks(tasks)
-	r.spawnRate = spawnRate
-	r.spawnCount = spawnCount
-	r.stopChan = make(chan bool)
-
-	if rateLimiter != nil {
-		r.rateLimitEnabled = true
-		r.rateLimiter = rateLimiter
+func newLocalRunner(spawnCount int, spawnRate float64) *localRunner {
+	return &localRunner{
+		runner: runner{
+			state:      stateInit,
+			spawnRate:  spawnRate,
+			spawnCount: spawnCount,
+			stats:      newRequestStats(),
+			outputs:    make([]Output, 0),
+		},
+		stopChan: make(chan bool),
 	}
-
-	r.stats = newRequestStats()
-	return r
 }
 
 func (r *localRunner) start() {
@@ -240,6 +237,7 @@ func (r *localRunner) start() {
 	var ticker = time.NewTicker(reportStatsInterval)
 	for {
 		select {
+		// record stats
 		case t := <-r.stats.transactionChan:
 			r.stats.logTransaction(t.name, t.success, t.elapsedTime, t.contentSize)
 		case m := <-r.stats.requestSuccessChan:
@@ -247,28 +245,34 @@ func (r *localRunner) start() {
 		case n := <-r.stats.requestFailureChan:
 			r.stats.logRequest(n.requestType, n.name, n.responseTime, 0)
 			r.stats.logError(n.requestType, n.name, n.errMsg)
+		// report stats
 		case <-ticker.C:
 			data := r.stats.collectReportData()
 			data["user_count"] = atomic.LoadInt32(&r.currentClientsNum)
 			data["state"] = atomic.LoadInt32(&r.state)
 			r.outputOnEevent(data)
+		// stop
 		case <-r.stopChan:
+			atomic.StoreInt32(&r.state, stateQuitting)
+
 			// stop previous goroutines without blocking
 			// those goroutines will exit when r.safeRun returns
 			close(quitChan)
+
 			// stop rate limiter
 			if r.rateLimitEnabled {
 				r.rateLimiter.Stop()
 			}
+
 			// output teardown
 			r.outputOnStop()
+
+			atomic.StoreInt32(&r.state, stateStopped)
 			return
 		}
 	}
 }
 
 func (r *localRunner) stop() {
-	atomic.StoreInt32(&r.state, stateQuitting)
 	close(r.stopChan)
-	atomic.StoreInt32(&r.state, stateStopped)
 }
diff --git a/internal/boomer/runner_test.go b/internal/boomer/runner_test.go
index 16a3bc6e..22f6ad8b 100644
--- a/internal/boomer/runner_test.go
+++ b/internal/boomer/runner_test.go
@@ -84,7 +84,8 @@ func TestLocalRunner(t *testing.T) {
 		Name: "TaskA",
 	}
 	tasks := []*Task{taskA}
-	runner := newLocalRunner(tasks, nil, 2, 2)
+	runner := newLocalRunner(2, 2)
+	runner.setTasks(tasks)
 	go runner.start()
 	time.Sleep(4 * time.Second)
 	runner.stop()