diff --git a/benchmark/worker/benchmark_server.go b/benchmark/worker/benchmark_server.go
index 41c430a03..4a7072fe2 100644
--- a/benchmark/worker/benchmark_server.go
+++ b/benchmark/worker/benchmark_server.go
@@ -27,7 +27,7 @@ type benchmarkServer struct {
 	lastResetTime time.Time
 }
 
-func startBenchmarkServerWithSetup(setup *testpb.ServerConfig) (*benchmarkServer, error) {
+func startBenchmarkServerWithSetup(setup *testpb.ServerConfig, serverPort int) (*benchmarkServer, error) {
 	var opts []grpc.ServerOption
 
 	grpclog.Printf(" - server type: %v", setup.ServerType)
@@ -55,49 +55,43 @@ func startBenchmarkServerWithSetup(setup *testpb.ServerConfig) (*benchmarkServer
 	if setup.CoreLimit > 0 {
 		runtime.GOMAXPROCS(int(setup.CoreLimit))
 	} else {
-		// runtime.GOMAXPROCS(runtime.NumCPU())
 		runtime.GOMAXPROCS(1)
 	}
 
 	grpclog.Printf(" - core list: %v", setup.CoreList)
 	if len(setup.CoreList) > 0 {
-		// TODO core list
-		grpclog.Printf("specifying cores to run server on: %v", setup.CoreList)
+		return nil, grpc.Errorf(codes.InvalidArgument, "specifying core list is not supported")
 	}
 
 	grpclog.Printf(" - port: %v", setup.Port)
+	var port int
+	if setup.Port != 0 {
+		port = int(setup.Port)
+	} else if serverPort != 0 {
+		port = serverPort
+	}
 	grpclog.Printf(" - payload config: %v", setup.PayloadConfig)
 	var p int
 	var close func()
 	if setup.PayloadConfig != nil {
-		// TODO payload config
-		grpclog.Printf("payload config: %v", setup.PayloadConfig)
 		switch payload := setup.PayloadConfig.Payload.(type) {
 		case *testpb.PayloadConfig_BytebufParams:
 			opts = append(opts, grpc.CustomCodec(byteBufCodec{}))
-			p, close = benchmark.StartGenericServer(":"+strconv.Itoa(int(setup.Port)), payload.BytebufParams.ReqSize, payload.BytebufParams.RespSize, opts...)
+			p, close = benchmark.StartGenericServer(":"+strconv.Itoa(port), payload.BytebufParams.ReqSize, payload.BytebufParams.RespSize, opts...)
 		case *testpb.PayloadConfig_SimpleParams:
-			p, close = benchmark.StartServer(":"+strconv.Itoa(int(setup.Port)), opts...)
+			p, close = benchmark.StartServer(":"+strconv.Itoa(port), opts...)
 		case *testpb.PayloadConfig_ComplexParams:
+			return nil, grpc.Errorf(codes.InvalidArgument, "unsupported payload config: %v", setup.PayloadConfig)
 		default:
 			return nil, grpc.Errorf(codes.InvalidArgument, "unknow payload config: %v", setup.PayloadConfig)
 		}
 	} else {
 		// Start protobuf server is payload config is nil
-		p, close = benchmark.StartServer(":"+strconv.Itoa(int(setup.Port)), opts...)
+		p, close = benchmark.StartServer(":"+strconv.Itoa(port), opts...)
 	}
 
 	grpclog.Printf("benchmark server listening at port %v", p)
 
-	// temp := strings.Split(addr, ":")
-	// if len(temp) <= 0 {
-	// 	return nil, grpc.Errorf(codes.Internal, "benchmark test address not valid: %v", addr)
-	// }
-	// p, err := strconv.Atoi(temp[len(temp)-1])
-	// if err != nil {
-	// 	return nil, grpc.Errorf(codes.Internal, "%v", err)
-	// }
-
 	bs := &benchmarkServer{port: p, close: close, lastResetTime: time.Now()}
 	return bs, nil
 }
@@ -109,6 +103,7 @@ func (bs *benchmarkServer) getStats() *testpb.ServerStats {
 }
 
 func (bs *benchmarkServer) reset() {
+	// TODO wall time, sys time, user time
 	bs.mu.Lock()
 	defer bs.mu.Unlock()
 	bs.lastResetTime = time.Now()
diff --git a/benchmark/worker/main.go b/benchmark/worker/main.go
index dc4782dc3..006b46d84 100644
--- a/benchmark/worker/main.go
+++ b/benchmark/worker/main.go
@@ -1,10 +1,11 @@
 package main
 
 import (
+	"flag"
 	"io"
 	"net"
 	"runtime"
-	"sync"
+	"strconv"
 
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
@@ -14,8 +15,8 @@ import (
 )
 
 var (
-	ports = []string{":10000"}
-	// ports = []string{":10010"}
+	driverPort = flag.Int("driver_port", 10000, "port for communication with driver")
+	serverPort = flag.Int("server_port", 0, "port for operation as a server")
 )
 
 type byteBufCodec struct {
@@ -35,7 +36,9 @@ func (byteBufCodec) String() string {
 }
 
 type workerServer struct {
-	bs *benchmarkServer
+	bs         *benchmarkServer
+	stop       chan<- bool
+	serverPort int
 }
 
 func (s *workerServer) RunServer(stream testpb.WorkerService_RunServerServer) error {
@@ -57,7 +60,7 @@ func (s *workerServer) RunServer(stream testpb.WorkerService_RunServerServer) er
 		case *testpb.ServerArgs_Setup:
 			grpclog.Printf("server setup received:")
 
-			bs, err := startBenchmarkServerWithSetup(t.Setup)
+			bs, err := startBenchmarkServerWithSetup(t.Setup, s.serverPort)
 			if err != nil {
 				return err
 			}
@@ -100,25 +103,25 @@ func (s *workerServer) QuitWorker(ctx context.Context, in *testpb.Void) (*testpb
 	if s.bs != nil {
 		s.bs.close()
 	}
+	s.stop <- true
 	return &testpb.Void{}, nil
 }
 
 func main() {
-	var wg sync.WaitGroup
-	wg.Add(len(ports))
-	for i := 0; i < len(ports); i++ {
-		lis, err := net.Listen("tcp", ports[i])
-		if err != nil {
-			grpclog.Fatalf("failed to listen: %v", err)
-		}
-		grpclog.Printf("worker %d listening at port %v", i, ports[i])
-
-		s := grpc.NewServer()
-		testpb.RegisterWorkerServiceServer(s, &workerServer{})
-		go func() {
-			defer wg.Done()
-			s.Serve(lis)
-		}()
+	flag.Parse()
+	lis, err := net.Listen("tcp", ":"+strconv.Itoa(*driverPort))
+	if err != nil {
+		grpclog.Fatalf("failed to listen: %v", err)
 	}
-	wg.Wait()
+	grpclog.Printf("worker listening at port %v", *driverPort)
+
+	s := grpc.NewServer()
+	stop := make(chan bool)
+	testpb.RegisterWorkerServiceServer(s, &workerServer{
+		stop:       stop,
+		serverPort: *serverPort,
+	})
+	go s.Serve(lis)
+	<-stop
+	s.Stop()
 }