diff --git a/.gitignore b/.gitignore
index e6c41a1b..25d14856 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,8 +3,11 @@
 *.egg-info/
 *.eggs/
 *.so
+*.log
+*.csv
 build/
 
 *.pkl
 *.png
 **/log.txt
+.vscode/
diff --git a/benchmark/benchmark_latency.py b/benchmark/benchmark_latency.py
index 33ec6c49..f9c69661 100644
--- a/benchmark/benchmark_latency.py
+++ b/benchmark/benchmark_latency.py
@@ -8,7 +8,8 @@ import torch
 
 from cacheflow.master.simple_frontend import SimpleFrontend
 from cacheflow.master.server import (Server, add_server_arguments,
-                                     initialize_ray_cluster)
+                                     process_server_arguments,
+                                     initialize_cluster)
 from cacheflow.sampling_params import SamplingParams
 from cacheflow.utils import get_gpu_memory, get_cpu_memory
 
@@ -20,8 +21,8 @@ def main(args: argparse.Namespace):
 
     (num_nodes, num_devices_per_node, distributed_init_method,
     all_stage_devices) = (
-        initialize_ray_cluster(
-            address='local',
+        initialize_cluster(
+            use_ray=args.use_ray,
             pipeline_parallel_size=args.pipeline_parallel_size,
             tensor_parallel_size=args.tensor_parallel_size))
 
@@ -44,6 +45,7 @@ def main(args: argparse.Namespace):
         all_stage_devices=all_stage_devices,
         gpu_memory=get_gpu_memory(),
         cpu_memory=get_cpu_memory(),
+        use_ray=args.use_ray,
     )
 
     # Create a frontend.
@@ -91,7 +93,8 @@ def main(args: argparse.Namespace):
 
 
 if __name__ == '__main__':
-    parser = argparse.ArgumentParser(description='CacheFlow simple server.')
+    parser = argparse.ArgumentParser(
+        description='Benchmark the latency of decoding a single sentence.')
     parser = add_server_arguments(parser)
     parser.add_argument('--input-len', type=int, default=32)
     parser.add_argument('--output-len', type=int, default=128)
@@ -99,6 +102,7 @@ if __name__ == '__main__':
     parser.add_argument('--n', type=int, default=1)
     parser.add_argument('--use-beam-search', action='store_true')
     args = parser.parse_args()
+    args = process_server_arguments(args)
     args.max_num_batched_tokens = max(
         args.max_num_batched_tokens, args.batch_size * args.input_len)
     print(args)
diff --git a/benchmark/benchmark_text_completion.py b/benchmark/benchmark_text_completion.py
index e6741d57..55d602a0 100644
--- a/benchmark/benchmark_text_completion.py
+++ b/benchmark/benchmark_text_completion.py
@@ -11,7 +11,8 @@ from transformers import AutoConfig
 from benchmark.trace import generate_text_completion_requests
 from cacheflow.master.simple_frontend import SimpleFrontend
 from cacheflow.master.server import (Server, add_server_arguments,
-                                     initialize_ray_cluster)
+                                     process_server_arguments,
+                                     initialize_cluster)
 from cacheflow.sampling_params import SamplingParams
 from cacheflow.utils import get_gpu_memory, get_cpu_memory
 
@@ -25,8 +26,8 @@ def main(args: argparse.Namespace):
 
     (num_nodes, num_devices_per_node, distributed_init_method,
     all_stage_devices) = (
-        initialize_ray_cluster(
-            address='local',
+        initialize_cluster(
+            use_ray=args.use_ray,
             pipeline_parallel_size=args.pipeline_parallel_size,
             tensor_parallel_size=args.tensor_parallel_size))
 
@@ -49,6 +50,7 @@ def main(args: argparse.Namespace):
         all_stage_devices=all_stage_devices,
         gpu_memory=get_gpu_memory(),
         cpu_memory=get_cpu_memory(),
+        use_ray=args.use_ray,
         collect_stats=True,
         do_memory_analysis=args.do_memory_analysis,
     )
@@ -134,7 +136,7 @@ def main(args: argparse.Namespace):
                 finished.append({
                     'group_id': seq_group.group_id,
                     'seq_id': seq.seq_id,
-                    'arrival_time': arrival_time, 
+                    'arrival_time': arrival_time,
                     'finish_time': finish_time,
                     'prompt_len': seq.prompt_len,
                     'output_len': output_len,
@@ -225,8 +227,9 @@ def get_sampling_dir_name(
 
 
 if __name__ == '__main__':
-    parser = argparse.ArgumentParser(description='CacheFlow simple server.')
-    parser = add_server_arguments(parser) 
+    parser = argparse.ArgumentParser(
+        description='Benchmark the performance on a series of requests.')
+    parser = add_server_arguments(parser)
     parser.add_argument('--output-dir', type=str, help='path to output directory', default=None)
 
     parser.add_argument('--dataset', type=str, help='path to dataset', required=True)
@@ -246,6 +249,7 @@ if __name__ == '__main__':
     parser.add_argument('--n6-beam', type=float, help='ratio of requests with n=6 & beam search', default=0.0)
     parser.add_argument('--n8-beam', type=float, help='ratio of requests with n=8 & beam search', default=0.0)
     args = parser.parse_args()
+    args = process_server_arguments(args)
     if args.n1 + args.n2 + args.n3 + args.n4 + args.n6 + args.n2_beam + args.n4_beam + args.n6_beam + args.n8_beam != 1.0:
         raise ValueError('The ratios of requests must sum to 1.')
 
diff --git a/cacheflow/http_frontend/fastapi_frontend.py b/cacheflow/http_frontend/fastapi_frontend.py
index 20953631..a2ae6ce4 100644
--- a/cacheflow/http_frontend/fastapi_frontend.py
+++ b/cacheflow/http_frontend/fastapi_frontend.py
@@ -13,7 +13,8 @@ import uvicorn
 from cacheflow.sampling_params import SamplingParams
 from cacheflow.sequence import Sequence, SequenceGroup
 from cacheflow.master.server import (Server, add_server_arguments,
-                                     initialize_ray_cluster)
+                                     process_server_arguments,
+                                     initialize_cluster)
 from cacheflow.worker.controller import DeviceID
 from cacheflow.utils import Counter, get_gpu_memory, get_cpu_memory
 
@@ -33,17 +34,22 @@ class FastAPIFrontend:
         seed: int,
         swap_space: int,
         max_num_batched_tokens: int,
+        max_num_sequences: int,
         num_nodes: int,
         num_devices_per_node: int,
         distributed_init_method: str,
         all_stage_devices: List[List[DeviceID]],
+        server_use_ray: bool,
     ):
         self.block_size = block_size
 
         self.tokenizer = AutoTokenizer.from_pretrained(model)
         self.seq_group_counter = Counter()
         self.seq_counter = Counter()
-        remote_server_class = ray.remote(num_cpus=0)(Server)
+        if server_use_ray:
+            remote_server_class = ray.remote(num_cpus=0)(Server)
+        else:
+            remote_server_class = ray.remote(num_gpus=1)(Server)
         self.server = remote_server_class.remote(
             model=model,
             model_path=model_path,
@@ -55,12 +61,14 @@ class FastAPIFrontend:
             seed=seed,
             swap_space=swap_space,
             max_num_batched_tokens=max_num_batched_tokens,
+            max_num_sequences=max_num_sequences,
             num_nodes=num_nodes,
             num_devices_per_node=num_devices_per_node,
             distributed_init_method=distributed_init_method,
             all_stage_devices=all_stage_devices,
             gpu_memory=get_gpu_memory(),
             cpu_memory=get_cpu_memory(),
+            use_ray=server_use_ray,
         )
 
         self.running_seq_groups: Dict[int, SequenceGroup] = {}
@@ -149,6 +157,7 @@ if __name__ == "__main__":
     parser.add_argument("--port", type=int, default=10002)
     parser = add_server_arguments(parser)
     args = parser.parse_args()
+    args = process_server_arguments(args)
 
     # TODO(zhuohan): Support pipeline parallelism.
     assert args.pipeline_parallel_size == 1, (
@@ -156,7 +165,8 @@ if __name__ == "__main__":
 
     (num_nodes, num_devices_per_node, distributed_init_method,
     all_stage_devices) = (
-        initialize_ray_cluster(
+        initialize_cluster(
+            use_ray=True,
             pipeline_parallel_size=args.pipeline_parallel_size,
             tensor_parallel_size=args.tensor_parallel_size))
 
@@ -170,10 +180,12 @@ if __name__ == "__main__":
         seed=args.seed,
         swap_space=args.swap_space,
         max_num_batched_tokens=args.max_num_batched_tokens,
+        max_num_sequences=args.max_num_sequences,
         num_nodes=num_nodes,
         num_devices_per_node=num_devices_per_node,
         distributed_init_method=distributed_init_method,
         all_stage_devices=all_stage_devices,
+        server_use_ray=args.use_ray,
     )
 
     uvicorn.run(app, host=args.host, port=args.port, log_level="info")
diff --git a/cacheflow/master/server.py b/cacheflow/master/server.py
index 5b8110a3..31125180 100644
--- a/cacheflow/master/server.py
+++ b/cacheflow/master/server.py
@@ -1,8 +1,12 @@
 import argparse
-from typing import List, Tuple
+from typing import List, Tuple, Optional
 import random
 
-import ray
+import torch
+try:
+    import ray
+except ImportError:
+    ray = None
 
 from cacheflow.master.scheduler import Scheduler
 from cacheflow.models import get_memory_analyzer
@@ -31,6 +35,7 @@ class Server:
         all_stage_devices: List[List[DeviceID]],
         gpu_memory: int,
         cpu_memory: int,
+        use_ray: bool,
         collect_stats: bool = False,
         do_memory_analysis: bool = False,
     ):
@@ -38,6 +43,10 @@ class Server:
         self.num_devices_per_node = num_devices_per_node
         self.world_size = pipeline_parallel_size * tensor_parallel_size
 
+        if not use_ray:
+            assert self.world_size == 1, (
+                "Only support single GPU without Ray.")
+
         self.memory_analyzer = get_memory_analyzer(
             model_name=model,
             block_size=block_size,
@@ -72,6 +81,7 @@ class Server:
                 model_path=model_path,
                 use_dummy_weights=use_dummy_weights,
                 max_num_batched_tokens=max_num_batched_tokens,
+                use_ray=use_ray,
             )
             self.controllers.append(controller)
 
@@ -105,11 +115,30 @@ class Server:
                 self.scheduler.swapped)
 
 
-def initialize_ray_cluster(
-    address: str = 'auto',
+def initialize_cluster(
+    use_ray: bool = False,
+    address: Optional[str] = None,
     pipeline_parallel_size: int = 1,
     tensor_parallel_size: int = 1,
 ) -> Tuple[int, int, str, List[List[DeviceID]]]:
+    # Initialize cluster locally.
+    if not use_ray:
+        assert pipeline_parallel_size * tensor_parallel_size == 1, (
+            "Only support single GPU without Ray.")
+        num_nodes = 1
+        num_devices_per_node = torch.cuda.device_count()
+        port = random.randint(10000, 20000)
+        # We need to setup the distributed init method to make sure
+        # the distributed megatron code (e.g., get world size) works correctly.
+        distributed_init_method = f"tcp://localhost:{port}"
+        all_stage_devices = [[(0, None, 0)]]
+        return (num_nodes, num_devices_per_node, distributed_init_method,
+                all_stage_devices)
+
+    assert ray is not None, (
+        "Ray is not installed. Please install Ray to use distributed "
+        "serving.")
+
     # Connect to a ray cluster.
     ray.init(address=address)
 
@@ -177,6 +206,7 @@ def add_server_arguments(parser: argparse.ArgumentParser):
     parser.add_argument('--model-path', type=str, default='~/.cacheflow/model_weights',
                         help='model path to download and load the weights')
     # Parallel arguments
+    parser.add_argument('--use-ray', action='store_true', help='use Ray for distributed serving, will be automatically set when using more than 1 GPU')
     parser.add_argument('--pipeline-parallel-size', '-pp', type=int, default=1, help='number of pipeline stages')
     parser.add_argument('--tensor-parallel-size', '-tp', type=int, default=1, help='number of tensor parallel replicas')
     # KV cache arguments
@@ -190,3 +220,8 @@ def add_server_arguments(parser: argparse.ArgumentParser):
     parser.add_argument('--max-num-sequences', type=int, default=256, help='maximum number of sequences per iteration')
     parser.add_argument('--use-dummy-weights', action='store_true', help='use dummy values for model weights')
     return parser
+
+def process_server_arguments(args: argparse.Namespace):
+    if args.pipeline_parallel_size * args.tensor_parallel_size > 1:
+        args.use_ray = True
+    return args
diff --git a/cacheflow/worker/controller.py b/cacheflow/worker/controller.py
index dce3fddf..7c3d66cc 100644
--- a/cacheflow/worker/controller.py
+++ b/cacheflow/worker/controller.py
@@ -1,6 +1,9 @@
 from typing import Dict, List, Union, Tuple
 
-import ray
+try:
+    import ray
+except ImportError:
+    ray = None
 
 from cacheflow.master.scheduler import Scheduler
 from cacheflow.sequence import SequenceGroupInputs
@@ -29,6 +32,7 @@ class Controller:
         model_path: str,
         use_dummy_weights: bool,
         max_num_batched_tokens: int,
+        use_ray: bool,
     ) -> None:
         self.stage_id = stage_id
         self.stage_devices = stage_devices
@@ -36,6 +40,7 @@ class Controller:
         self.block_size = block_size
         self.num_gpu_blocks = num_gpu_blocks
         self.num_cpu_blocks = num_cpu_blocks
+        self.use_ray = use_ray
 
         # Which pipeline stage is this node assigned to?
         self.is_first_stage = stage_id == 0
@@ -43,10 +48,13 @@ class Controller:
 
         self.workers: List[Worker] = []
         for rank, node_resource, device_id in stage_devices:
-            worker_cls = ray.remote(num_cpus=0,
-                                    num_gpus=1,
-                                    resources={node_resource: 1e-5})(Worker)
-            worker = worker_cls.remote(
+            if self.use_ray:
+                worker_cls = ray.remote(num_cpus=0,
+                                        num_gpus=1,
+                                        resources={node_resource: 1e-5})(Worker).remote
+            else:
+                worker_cls = Worker
+            worker = worker_cls(
                 model_name=model_name,
                 block_size=block_size,
                 num_gpu_blocks=num_gpu_blocks,
@@ -78,17 +86,21 @@ class Controller:
         blocks_to_swap_out: Dict[int, int],
         blocks_to_copy: Dict[int, List[int]],
     ) -> None:
-        futures = []
+        all_outputs = []
         for worker in self.workers:
-            future = worker.execute_stage.remote(
+            executor = (worker.execute_stage.remote
+                        if self.use_ray else worker.execute_stage)
+            output = executor(
                 input_seq_groups,
                 blocks_to_swap_in,
                 blocks_to_swap_out,
                 blocks_to_copy,
             )
-            futures.append(future)
+            all_outputs.append(output)
+
+        if self.use_ray:
+            all_outputs = ray.get(all_outputs)
 
-        all_outputs = ray.get(futures)
         # Make sure all workers have the same results.
         output = all_outputs[0]
         for other_output in all_outputs[1:]:
diff --git a/simple_server.py b/simple_server.py
index 17df72af..0c0c7cb4 100644
--- a/simple_server.py
+++ b/simple_server.py
@@ -3,7 +3,8 @@ from typing import List
 
 from cacheflow.master.simple_frontend import SimpleFrontend
 from cacheflow.master.server import (Server, add_server_arguments,
-                                     initialize_ray_cluster)
+                                     process_server_arguments,
+                                     initialize_cluster)
 from cacheflow.sampling_params import SamplingParams
 from cacheflow.utils import get_gpu_memory, get_cpu_memory
 
@@ -14,7 +15,8 @@ def main(args: argparse.Namespace):
 
     (num_nodes, num_devices_per_node, distributed_init_method,
     all_stage_devices) = (
-        initialize_ray_cluster(
+        initialize_cluster(
+            use_ray=args.use_ray,
             pipeline_parallel_size=args.pipeline_parallel_size,
             tensor_parallel_size=args.tensor_parallel_size))
 
@@ -37,6 +39,7 @@ def main(args: argparse.Namespace):
         all_stage_devices=all_stage_devices,
         gpu_memory=get_gpu_memory(),
         cpu_memory=get_cpu_memory(),
+        use_ray=args.use_ray,
     )
 
     # Create a frontend.
@@ -70,4 +73,5 @@ if __name__ == '__main__':
     parser = argparse.ArgumentParser(description='CacheFlow simple server.')
     parser = add_server_arguments(parser)
     args = parser.parse_args()
+    args = process_server_arguments(args)
     main(args)