diff --git a/go.mod b/go.mod
index 2f8cd00..923c9d5 100644
--- a/go.mod
+++ b/go.mod
@@ -5,10 +5,12 @@ go 1.21
 toolchain go1.21.1
 
 require (
+	github.com/google/uuid v1.3.0
 	github.com/grpc-ecosystem/go-grpc-middleware/v2 v2.0.0
 	github.com/oklog/run v1.1.0
 	github.com/spf13/cobra v1.7.0
 	github.com/stretchr/testify v1.8.4
+	golang.org/x/sync v0.3.0
 	google.golang.org/grpc v1.58.1
 	google.golang.org/protobuf v1.31.0
 	k8s.io/cri-api v0.28.2
@@ -23,6 +25,7 @@ require (
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/emicklei/go-restful/v3 v3.9.0 // indirect
+	github.com/evanphx/json-patch/v5 v5.6.0 // indirect
 	github.com/felixge/httpsnoop v1.0.3 // indirect
 	github.com/go-logr/logr v1.2.4 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
@@ -36,6 +39,7 @@ require (
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0 // indirect
+	github.com/imdario/mergo v0.3.6 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
@@ -44,8 +48,7 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/onsi/ginkgo/v2 v2.11.0 // indirect
-	github.com/onsi/gomega v1.27.10 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.16.0 // indirect
 	github.com/prometheus/client_model v0.4.0 // indirect
diff --git a/internal/daemon/api.go b/internal/daemon/api.go
index cad51f0..f8bee1b 100644
--- a/internal/daemon/api.go
+++ b/internal/daemon/api.go
@@ -6,16 +6,18 @@ import (
 	"time"
 
 	"github.com/cybozu-go/necoperf/internal/rpc"
+	"golang.org/x/sync/errgroup"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )
 
 const (
-	maxTimeout = 10 * time.Minute // 10 minute
+	maxTimeout    = 10 * time.Minute // 10 minute
+	maxConcurrent = 2
 )
 
 func (d *DaemonServer) Profile(req *rpc.PerfProfileRequest, stream rpc.NecoPerf_ProfileServer) error {
-	ctx := stream.Context()
+	eg, ctx := errgroup.WithContext(stream.Context())
 	containerID := req.GetContainerId()
 	if len(containerID) == 0 {
 		err := status.Error(codes.InvalidArgument, "container ID is not set")
@@ -41,17 +43,35 @@ func (d *DaemonServer) Profile(req *rpc.PerfProfileRequest, stream rpc.NecoPerf_
 		err := status.Error(codes.Internal, "invalid PID is returned from CRI API")
 		return err
 	}
-	profileDataPath, err := d.perfExecuter.ExecRecord(ctx, d.workDir, pid, timeout)
+
+	var scriptDataPath string
+	defer os.Remove(scriptDataPath)
+
+	err = d.semaphore.Acquire(ctx, maxConcurrent)
 	if err != nil {
 		return err
 	}
-	defer os.Remove(profileDataPath)
 
-	scriptDataPath, err := d.perfExecuter.ExecScript(ctx, profileDataPath, d.workDir)
-	if err != nil {
+	eg.Go(func() error {
+		defer d.semaphore.Release(1)
+
+		profileDataPath, err := d.perfExecuter.ExecRecord(ctx, d.workDir, pid, timeout)
+		defer os.Remove(profileDataPath)
+		if err != nil {
+			return err
+		}
+
+		scriptDataPath, err = d.perfExecuter.ExecScript(ctx, profileDataPath, d.workDir)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+
+	if err := eg.Wait(); err != nil {
 		return err
 	}
-	defer os.Remove(scriptDataPath)
 
 	f, err := os.Open(scriptDataPath)
 	if err != nil {
diff --git a/internal/daemon/daemon.go b/internal/daemon/daemon.go
index 4940e03..7c2e326 100644
--- a/internal/daemon/daemon.go
+++ b/internal/daemon/daemon.go
@@ -12,6 +12,7 @@ import (
 	"github.com/cybozu-go/necoperf/internal/rpc"
 	"github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
 	"github.com/oklog/run"
+	"golang.org/x/sync/semaphore"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/health"
 	healthpb "google.golang.org/grpc/health/grpc_health_v1"
@@ -21,11 +22,12 @@ import (
 )
 
 type DaemonServer struct {
-	logger   *slog.Logger
-	server   *grpc.Server
-	port     int
-	endpoint string
-	workDir  string
+	logger    *slog.Logger
+	server    *grpc.Server
+	port      int
+	endpoint  string
+	workDir   string
+	semaphore *semaphore.Weighted
 	rpc.UnimplementedNecoPerfServer
 	container    *resource.Container
 	perfExecuter *resource.PerfExecuter
@@ -34,6 +36,7 @@ type DaemonServer struct {
 const (
 	minTime    = 30 * time.Second
 	criTimeout = 30 * time.Second
+	maxWorkers = 3
 )
 
 func New(logger *slog.Logger, port int, endpoint, workDir string) (*DaemonServer, error) {
@@ -57,12 +60,15 @@ func New(logger *slog.Logger, port int, endpoint, workDir string) (*DaemonServer
 		),
 	)
 
+	w := semaphore.NewWeighted(maxWorkers)
+
 	return &DaemonServer{
-		logger:   logger,
-		server:   serv,
-		port:     port,
-		endpoint: endpoint,
-		workDir:  workDir,
+		logger:    logger,
+		server:    serv,
+		port:      port,
+		endpoint:  endpoint,
+		workDir:   workDir,
+		semaphore: w,
 	}, nil
 }