diff --git a/cmd/benchmark/test_command.go b/cmd/benchmark/test_command.go
index 1b341b643..32beac2c3 100644
--- a/cmd/benchmark/test_command.go
+++ b/cmd/benchmark/test_command.go
@@ -60,6 +60,11 @@ var (
 		Name:  "print-json",
 		Usage: "Print json output if it is set",
 	}
+	flagPipelineSize = &cli.IntFlag{
+		Name:  "pipeline-size",
+		Usage: "Pipeline size, no pipelined requests if zero. Not support per-target pipeline size yet.",
+		Value: 0,
+	}
 )
 
 func newCommandTest() *cli.Command {
@@ -77,6 +82,7 @@ func newCommandTest() *cli.Command {
 			flagDuration,
 			flagReportInterval,
 			flagPrintJSON,
+			flagPipelineSize,
 		},
 		Action: runCommandTest,
 	}
@@ -109,6 +115,7 @@ func runCommandTest(c *cli.Context) error {
 				return fmt.Errorf("malformed target %s: invalid log stream %s", str, toks[1])
 			}
 		}
+		target.PipelineSize = c.Int(flagPipelineSize.Name)
 		targets[idx] = target
 	}
 
diff --git a/internal/benchmark/loader.go b/internal/benchmark/loader.go
index b086a06ec..805242903 100644
--- a/internal/benchmark/loader.go
+++ b/internal/benchmark/loader.go
@@ -120,50 +120,110 @@ func (loader *Loader) Close() error {
 	return err
 }
 
-func (loader *Loader) appendLoop(ctx context.Context, c varlog.Log) error {
+func (loader *Loader) makeAppendFunc(ctx context.Context, c varlog.Log, am *AppendMetrics) (appendFunc func(), closeFunc func()) {
 	begin := true
-	var am AppendMetrics
-	for {
-		select {
-		case <-ctx.Done():
-			return ctx.Err()
-		default:
+	notifyBegin := func(meta varlogpb.LogEntryMeta) {
+		loader.begin.ch <- varlogpb.LogSequenceNumber{
+			LLSN: meta.LLSN,
+			GLSN: meta.GLSN,
 		}
+		begin = false
+	}
 
-		ts := time.Now()
-		var res varlog.AppendResult
-		if loader.LogStreamID.Invalid() {
-			res = c.Append(ctx, loader.TopicID, loader.batch)
-		} else {
-			res = c.AppendTo(ctx, loader.TopicID, loader.LogStreamID, loader.batch)
-		}
-		dur := time.Since(ts)
-		if res.Err != nil {
-			return fmt.Errorf("append: %w", res.Err)
-		}
-		if begin {
-			loader.begin.ch <- varlogpb.LogSequenceNumber{
-				LLSN: res.Metadata[0].LLSN,
-				GLSN: res.Metadata[0].GLSN,
-			}
-			begin = false
-		}
-		cnt := len(res.Metadata)
+	debugLog := func(meta []varlogpb.LogEntryMeta) {
+		cnt := len(meta)
+		loader.logger.Debug("append",
+			slog.Int("count", cnt),
+			slog.Any("logstream", meta[0].LogStreamID),
+			slog.Any("firstGLSN", meta[0].GLSN),
+			slog.Any("lastGLSN", meta[cnt-1].GLSN),
+			slog.Any("firstLLSN", meta[0].LLSN),
+			slog.Any("lastLLSN", meta[cnt-1].LLSN),
+		)
+	}
+
+	recordMetrics := func(dur time.Duration) {
 		am.bytes += int64(loader.BatchSize * loader.MessageSize)
 		am.requests++
 		am.durationMS += dur.Milliseconds()
-		if loader.metrics.ReportAppendMetrics(am) {
-			am = AppendMetrics{}
+		if loader.metrics.ReportAppendMetrics(*am) {
+			*am = AppendMetrics{}
 		}
+	}
 
-		loader.logger.Debug("append",
-			slog.Int("count", cnt),
-			slog.Any("logstream", res.Metadata[0].LogStreamID),
-			slog.Any("firstGLSN", res.Metadata[0].GLSN),
-			slog.Any("lastGLSN", res.Metadata[cnt-1].GLSN),
-			slog.Any("firstLLSN", res.Metadata[0].LLSN),
-			slog.Any("lastLLSN", res.Metadata[cnt-1].LLSN),
-		)
+	tpid, lsid := loader.TopicID, loader.LogStreamID
+
+	closeFunc = func() {}
+	if lsid.Invalid() {
+		return func() {
+			ts := time.Now()
+			res := c.Append(ctx, loader.TopicID, loader.batch)
+			if res.Err != nil {
+				panic(res.Err)
+			}
+			dur := time.Since(ts)
+			recordMetrics(dur)
+			if begin {
+				notifyBegin(res.Metadata[0])
+			}
+			debugLog(res.Metadata)
+		}, closeFunc
+	}
+
+	if loader.PipelineSize == 0 {
+		return func() {
+			ts := time.Now()
+			res := c.AppendTo(ctx, tpid, lsid, loader.batch)
+			if res.Err != nil {
+				panic(res.Err)
+			}
+			dur := time.Since(ts)
+			recordMetrics(dur)
+			if begin {
+				notifyBegin(res.Metadata[0])
+			}
+			debugLog(res.Metadata)
+		}, closeFunc
+	}
+
+	lsa, err := c.NewLogStreamAppender(loader.TopicID, loader.LogStreamID,
+		varlog.WithPipelineSize(loader.PipelineSize),
+	)
+	if err != nil {
+		panic(err)
+	}
+	closeFunc = lsa.Close
+	return func() {
+		ts := time.Now()
+		err := lsa.AppendBatch(loader.batch, func(lem []varlogpb.LogEntryMeta, err error) {
+			if err != nil {
+				panic(err)
+			}
+			dur := time.Since(ts)
+			recordMetrics(dur)
+			if begin {
+				notifyBegin(lem[0])
+			}
+			debugLog(lem)
+		})
+		if err != nil {
+			panic(err)
+		}
+	}, closeFunc
+}
+
+func (loader *Loader) appendLoop(ctx context.Context, c varlog.Log) error {
+	var am AppendMetrics
+	appendFunc, closeFunc := loader.makeAppendFunc(ctx, c, &am)
+	defer closeFunc()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+			appendFunc()
+		}
 	}
 }
 
diff --git a/internal/benchmark/target.go b/internal/benchmark/target.go
index 8c92990f0..ec2f516f9 100644
--- a/internal/benchmark/target.go
+++ b/internal/benchmark/target.go
@@ -14,6 +14,7 @@ type Target struct {
 	BatchSize        uint
 	AppendersCount   uint
 	SubscribersCount uint
+	PipelineSize     int
 }
 
 func (tgt Target) Valid() error {