Add script for benchmarking serving throughput (#145)

Author: WoosukKwon

benchmarks/benchmark_async_llm_server.py

@@ -10,6 +10,7 @@ def main(args: argparse.Namespace):
     prompts = [f"Tell me a story with more than {''.join([str(i+1)] * 5)} words"
               for i in range(args.n_threads)]
 
+    api_url = f"http://{args.host}:{args.port}/generate"
     headers = {"User-Agent": "CacheFlow Benchmark Client"}
     ploads = [{
         "prompt": p,
@@ -19,8 +20,8 @@ def main(args: argparse.Namespace):
     } for p in prompts]
 
     def send_request(results, i):
-        response = requests.post(args.api_url, headers=headers,
-                                 json=ploads[i], stream=True)
+        response = requests.post(api_url, headers=headers, json=ploads[i],
+                                 stream=True)
         results[i] = response
 
     # use args.n_threads to prompt the backend
@@ -50,7 +51,8 @@ def send_request(results, i):
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
-    parser.add_argument("--api-url", type=str, default="http://localhost:8001/generate")
+    parser.add_argument("--host", type=str, default="localhost")
+    parser.add_argument("--port", type=int, default=8001)
     parser.add_argument("--max-tokens", type=int, default=128)
     parser.add_argument("--n-threads", type=int, default=128)
     args = parser.parse_args()

benchmarks/benchmark_latency.py

@@ -1,3 +1,4 @@
+"""Benchmark the latency of processing a single batch of requests."""
 import argparse
 import time
 

benchmarks/benchmark_serving.py

@@ -0,0 +1,237 @@
+"""Benchmark online serving throughput.
+
+On the server side, run one of the following commands:
+    (CacheFlow backend)
+    python -m cacheflow.entrypoints.simple_fastapi_frontend \
+        --disable-log-requests --model <your_model>
+
+    (TGI backend)
+    ./launch_hf_server.sh <your_model>
+
+On the client side, run:
+    python benchmarks/benchmark_serving.py \
+        --backend <backend> \
+        --tokenizer <your_model> --dataset <target_dataset> \
+        --request-rate <request_rate>
+"""
+import argparse
+import asyncio
+import json
+import random
+import time
+from typing import AsyncGenerator, List, Tuple
+
+import aiohttp
+import numpy as np
+from transformers import AutoConfig, AutoTokenizer, PreTrainedTokenizerBase
+
+# (prompt len, output len, latency)
+REQUEST_LATENCY: List[Tuple[int, int, float]] = []
+
+
+def get_tokenizer(model_name: str) -> PreTrainedTokenizerBase:
+    config = AutoConfig.from_pretrained(model_name)
+    if config.model_type == "llama":
+        # A workaround for potential protobuf errors.
+        model_name = "hf-internal-testing/llama-tokenizer"
+    return AutoTokenizer.from_pretrained(model_name)
+
+
+def sample_requests(
+    dataset_path: str,
+    num_requests: int,
+    tokenizer: PreTrainedTokenizerBase,
+) -> List[Tuple[str, int, int]]:
+    # Load the dataset.
+    with open(dataset_path) as f:
+        dataset = json.load(f)
+    # Filter out the conversations with less than 2 turns.
+    dataset = [
+        data for data in dataset
+        if len(data["conversations"]) >= 2
+    ]
+    # Only keep the first two turns of each conversation.
+    dataset = [
+        (data["conversations"][0]["value"], data["conversations"][1]["value"])
+        for data in dataset
+    ]
+
+    # Tokenize the prompts and completions.
+    prompts = [prompt for prompt, _ in dataset]
+    prompt_token_ids = tokenizer(prompts).input_ids
+    completions = [completion for _, completion in dataset]
+    completion_token_ids = tokenizer(completions).input_ids
+    tokenized_dataset = []
+    for i in range(len(dataset)):
+        output_len = len(completion_token_ids[i])
+        tokenized_dataset.append((prompts[i], prompt_token_ids[i], output_len))
+
+    # Filter out too long sequences.
+    filtered_dataset: List[Tuple[str, int, int]] = []
+    for prompt, prompt_token_ids, output_len in tokenized_dataset:
+        prompt_len = len(prompt_token_ids)
+        if prompt_len < 4 or output_len < 4:
+            # Prune too short sequences.
+            # This is because TGI causes errors when the input or output length
+            # is too short.
+            continue
+        if prompt_len > 1024 or prompt_len + output_len > 2048:
+            # Prune too long sequences.
+            continue
+        filtered_dataset.append((prompt, prompt_len, output_len))
+
+    # Sample the requests.
+    sampled_requests = random.sample(filtered_dataset, num_requests)
+    return sampled_requests
+
+
+async def get_request(
+    input_requests: List[Tuple[str, int, int]],
+    request_rate: float,
+) -> AsyncGenerator[Tuple[str, int, int], None]:
+    input_requests = iter(input_requests)
+    for request in input_requests:
+        yield request
+
+        if request_rate == float("inf"):
+            # If the request rate is infinity, then we don't need to wait.
+            continue
+        # Sample the request interval from the exponential distribution.
+        interval = np.random.exponential(1.0 / request_rate)
+        # The next request will be sent after the interval.
+        await asyncio.sleep(interval)
+
+
+async def send_request(
+    backend: str,
+    api_url: str,
+    prompt: str,
+    prompt_len: int,
+    output_len: int,
+    best_of: int,
+    use_beam_search: bool,
+) -> None:
+    request_start_time = time.time()
+
+    headers = {"User-Agent": "Benchmark Client"}
+    if backend == "cacheflow":
+        pload = {
+            "prompt": prompt,
+            "n": 1,
+            "best_of": best_of,
+            "use_beam_search": use_beam_search,
+            "temperature": 0.0 if use_beam_search else 1.0,
+            "top_p": 1.0,
+            "max_tokens": output_len,
+            "ignore_eos": True,
+            "stream": False,
+        }
+    elif backend == "tgi":
+        assert not use_beam_search
+        params = {
+            "best_of": best_of,
+            "max_new_tokens": output_len,
+            "do_sample": True,
+        }
+        pload = {
+            "inputs": prompt,
+            "parameters": params,
+        }
+    else:
+        raise ValueError(f"Unknown backend: {backend}")
+
+    timeout = aiohttp.ClientTimeout(total=3 * 3600)
+    async with aiohttp.ClientSession(timeout=timeout) as session:
+        while True:
+            async with session.post(api_url, headers=headers, json=pload) as response:
+                chunks = []
+                async for chunk, _ in response.content.iter_chunks():
+                    chunks.append(chunk)
+            output = b"".join(chunks).decode("utf-8")
+            output = json.loads(output)
+
+            # Re-send the request if it failed.
+            if "error" not in output:
+                break
+
+    request_end_time = time.time()
+    request_latency = request_end_time - request_start_time
+    REQUEST_LATENCY.append((prompt_len, output_len, request_latency))
+
+
+async def benchmark(
+    backend: str,
+    api_url: str,
+    input_requests: List[Tuple[str, int, int]],
+    best_of: int,
+    use_beam_search: bool,
+    request_rate: float,
+) -> None:
+    tasks: List[asyncio.Task] = []
+    async for request in get_request(input_requests, request_rate):
+        prompt, prompt_len, output_len = request
+        task = asyncio.create_task(send_request(backend, api_url, prompt,
+                                                prompt_len, output_len,
+                                                best_of, use_beam_search))
+        tasks.append(task)
+    await asyncio.gather(*tasks)
+
+
+def main(args: argparse.Namespace):
+    print(args)
+    random.seed(args.seed)
+    np.random.seed(args.seed)
+
+    api_url = f"http://{args.host}:{args.port}/generate"
+    tokenizer = get_tokenizer(args.tokenizer)
+    input_requests = sample_requests(args.dataset, args.num_prompts, tokenizer)
+
+    benchmark_start_time = time.time()
+    asyncio.run(benchmark(args.backend, api_url, input_requests, args.best_of,
+                          args.use_beam_search, args.request_rate))
+    benchmark_end_time = time.time()
+    benchmark_time = benchmark_end_time - benchmark_start_time
+    print(f"Total time: {benchmark_time:.2f} s")
+    print(f"Throughput: {args.num_prompts / benchmark_time:.2f} requests/s")
+
+    # Compute the latency statistics.
+    avg_latency = np.mean([latency for _, _, latency in REQUEST_LATENCY])
+    print(f"Average latency: {avg_latency:.2f} s")
+    avg_per_token_latency = np.mean([
+        latency / (prompt_len + output_len)
+        for prompt_len, output_len, latency in REQUEST_LATENCY
+    ])
+    print(f"Average latency per token: {avg_per_token_latency:.2f} s")
+    avg_per_output_token_latency = np.mean([
+        latency / output_len
+        for _, output_len, latency in REQUEST_LATENCY
+    ])
+    print("Average latency per output token: "
+          f"{avg_per_output_token_latency:.2f} s")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Benchmark the online serving throughput.")
+    parser.add_argument("--backend", type=str, default="cacheflow",
+                        choices=["cacheflow", "tgi"])
+    parser.add_argument("--host", type=str, default="localhost")
+    parser.add_argument("--port", type=int, default=8001)
+    parser.add_argument("--dataset", type=str, required=True,
+                        help="Path to the dataset.")
+    parser.add_argument("--tokenizer", type=str, required=True,
+                        help="Name or path of the tokenizer.")
+    parser.add_argument("--best-of", type=int, default=1,
+                        help="Generates `best_of` sequences per prompt and "
+                             "returns the best one.")
+    parser.add_argument("--use-beam-search", action="store_true")
+    parser.add_argument("--num-prompts", type=int, default=1000,
+                        help="Number of prompts to process.")
+    parser.add_argument("--request-rate", type=float, default=float("inf"),
+                        help="Number of requests per second. If this is inf, "
+                             "then all the requests are sent at time 0. "
+                             "Otherwise, we use Poisson process to synthesize "
+                             "the request arrival times.")
+    parser.add_argument("--seed", type=int, default=0)
+    args = parser.parse_args()
+    main(args)