# SPDX-License-Identifier: Apache-2.0
"""Benchmark the latency of processing a single batch of requests."""
import argparse
import dataclasses
import json
import os
import time
from pathlib import Path
from typing import Any, Dict, List, Optional
import numpy as np
import torch
from benchmark_utils import convert_to_pytorch_benchmark_format
from tqdm import tqdm
from vllm import LLM, SamplingParams
from vllm.engine.arg_utils import EngineArgs
from vllm.inputs import PromptType
from vllm.sampling_params import BeamSearchParams
from vllm.utils import FlexibleArgumentParser
def save_to_pytorch_benchmark_format(args: argparse.Namespace,
results: Dict[str, Any]) -> None:
pt_records = convert_to_pytorch_benchmark_format(
args=args,
metrics={"latency": results["latencies"]},
extra_info={k: results[k]
for k in ["avg_latency", "percentiles"]})
if pt_records:
pt_file = f"{os.path.splitext(args.output_json)[0]}.pytorch.json"
with open(pt_file, "w") as f:
json.dump(pt_records, f)
def main(args: argparse.Namespace):
print(args)
engine_args = EngineArgs.from_cli_args(args)
# NOTE(woosuk): If the request cannot be processed in a single batch,
# the engine will automatically process the request in multiple batches.
llm = LLM(**dataclasses.asdict(engine_args))
assert llm.llm_engine.model_config.max_model_len >= (
args.input_len +
args.output_len), ("Please ensure that max_model_len is greater than"
" the sum of input_len and output_len.")
sampling_params = SamplingParams(
n=args.n,
temperature=1.0,
top_p=1.0,
ignore_eos=True,
max_tokens=args.output_len,
)
print(sampling_params)
dummy_prompt_token_ids = np.random.randint(10000,
size=(args.batch_size,
args.input_len))
dummy_prompts: List[PromptType] = [{
"prompt_token_ids": batch
} for batch in dummy_prompt_token_ids.tolist()]
def llm_generate():
if not args.use_beam_search:
llm.generate(dummy_prompts,
sampling_params=sampling_params,
use_tqdm=False)
else:
llm.beam_search(
dummy_prompts,
BeamSearchParams(
beam_width=args.n,
max_tokens=args.output_len,
ignore_eos=True,
),
)
def run_to_completion(profile_dir: Optional[str] = None):
if profile_dir:
with torch.profiler.profile(
activities=[
torch.profiler.ProfilerActivity.CPU,
torch.profiler.ProfilerActivity.CUDA,
],
on_trace_ready=torch.profiler.tensorboard_trace_handler(
str(profile_dir)),
) as p:
llm_generate()
print(p.key_averages().table(sort_by="self_cuda_time_total"))
else:
start_time = time.perf_counter()
llm_generate()
end_time = time.perf_counter()
latency = end_time - start_time
return latency
print("Warming up...")
for _ in tqdm(range(args.num_iters_warmup), desc="Warmup iterations"):
run_to_completion(profile_dir=None)
if args.profile:
profile_dir = args.profile_result_dir
if not profile_dir:
profile_dir = (Path(".") / "vllm_benchmark_result" /
f"latency_result_{time.time()}")
print(f"Profiling (results will be saved to '{profile_dir}')...")
run_to_completion(profile_dir=profile_dir)
return
# Benchmark.
latencies = []
for _ in tqdm(range(args.num_iters), desc="Profiling iterations"):
latencies.append(run_to_completion(profile_dir=None))
latencies = np.array(latencies)
percentages = [10, 25, 50, 75, 90, 99]
percentiles = np.percentile(latencies, percentages)
print(f"Avg latency: {np.mean(latencies)} seconds")
for percentage, percentile in zip(percentages, percentiles):
print(f"{percentage}% percentile latency: {percentile} seconds")
# Output JSON results if specified
if args.output_json:
results = {
"avg_latency": np.mean(latencies),
"latencies": latencies.tolist(),
"percentiles": dict(zip(percentages, percentiles.tolist())),
}
with open(args.output_json, "w") as f:
json.dump(results, f, indent=4)
save_to_pytorch_benchmark_format(args, results)
if __name__ == "__main__":
# vLLM 框架中自定义的参数解析器类,作用:命令行参数解析器
parser = FlexibleArgumentParser(
description="Benchmark the latency of processing a single batch of "# 字符串拼接技巧:使用引号分行的方式提高可读性
"requests till completion.")# 提供程序功能描述,会在帮助信息中显示
parser.add_argument("--input-len", type=int, default=32)
parser.add_argument("--output-len", type=int, default=128)
parser.add_argument("--batch-size", type=int, default=8)
parser.add_argument(
"--n",
type=int,
default=1,
help="Number of generated sequences per prompt.",
)
parser.add_argument("--use-beam-search", action="store_true")
parser.add_argument(
"--num-iters-warmup",
type=int,
default=10,
help="Number of iterations to run for warmup.",
)
parser.add_argument("--num-iters",
type=int,
default=30,
help="Number of iterations to run.")
parser.add_argument(
"--profile",
action="store_true",
help="profile the generation process of a single batch",
)
parser.add_argument(
"--profile-result-dir",
type=str,
default=None,
help=("path to save the pytorch profiler output. Can be visualized "
"with ui.perfetto.dev or Tensorboard."),
)
parser.add_argument(
"--output-json",
type=str,
default=None,
help="Path to save the latency results in JSON format.",
)
parser = EngineArgs.add_cli_args(parser)
args = parser.parse_args()
main(args)分析、解读代码执行逻辑,画出流程图