vllm.benchmarks.serve ¶

def _get_current_request_rate(
    ramp_up_strategy: Literal["linear", "exponential"] | None,
    ramp_up_start_rps: int | None,
    ramp_up_end_rps: int | None,
    request_index: int,
    total_requests: int,
    request_rate: float,
) -> float:
    if (
        ramp_up_strategy
        and ramp_up_start_rps is not None
        and ramp_up_end_rps is not None
    ):
        progress = request_index / max(total_requests - 1, 1)
        if ramp_up_strategy == "linear":
            increase = (ramp_up_end_rps - ramp_up_start_rps) * progress
            return ramp_up_start_rps + increase
        elif ramp_up_strategy == "exponential":
            ratio = ramp_up_end_rps / ramp_up_start_rps
            return ramp_up_start_rps * (ratio**progress)
        else:
            raise ValueError(f"Unknown ramp-up strategy: {ramp_up_strategy}")
    return request_rate

def add_cli_args(parser: argparse.ArgumentParser):
    add_dataset_parser(parser)
    parser.add_argument(
        "--label",
        type=str,
        default=None,
        help="The label (prefix) of the benchmark results. If not specified, "
        "the value of '--backend' will be used as the label.",
    )
    parser.add_argument(
        "--backend",
        type=str,
        default="openai",
        choices=list(ASYNC_REQUEST_FUNCS.keys()),
        help="The type of backend or endpoint to use for the benchmark.",
    )
    parser.add_argument(
        "--base-url",
        type=str,
        default=None,
        help="Server or API base url if not using http host and port.",
    )
    # Use 127.0.0.1 here instead of localhost to force the use of ipv4
    parser.add_argument("--host", type=str, default="127.0.0.1")
    parser.add_argument("--port", type=int, default=8000)
    parser.add_argument(
        "--endpoint",
        type=str,
        default="/v1/completions",
        help="API endpoint.",
    )
    parser.add_argument(
        "--header",
        metavar="KEY=VALUE",
        nargs="*",
        help="Key-value pairs (e.g, --header x-additional-info=0.3.3) "
        "for headers to be passed with each request. These headers override "
        "per backend constants and values set via environment variable, and "
        "will be overridden by other arguments (such as request ids).",
    )
    parser.add_argument(
        "--max-concurrency",
        type=int,
        default=None,
        help="Maximum number of concurrent requests. This can be used "
        "to help simulate an environment where a higher level component "
        "is enforcing a maximum number of concurrent requests. While the "
        "--request-rate argument controls the rate at which requests are "
        "initiated, this argument will control how many are actually allowed "
        "to execute at a time. This means that when used in combination, the "
        "actual request rate may be lower than specified with --request-rate, "
        "if the server is not processing requests fast enough to keep up.",
    )

    parser.add_argument(
        "--model",
        type=str,
        required=False,
        default=None,
        help="Name of the model. If not specified, will fetch the first model "
        "from the server's /v1/models endpoint.",
    )
    parser.add_argument(
        "--input-len",
        type=int,
        default=None,
        help="General input length for datasets. Maps to dataset-specific "
        "input length arguments (e.g., --random-input-len, --sonnet-input-len). "
        "If not specified, uses dataset defaults.",
    )
    parser.add_argument(
        "--output-len",
        type=int,
        default=None,
        help="General output length for datasets. Maps to dataset-specific "
        "output length arguments (e.g., --random-output-len, --sonnet-output-len). "
        "If not specified, uses dataset defaults.",
    )
    parser.add_argument(
        "--tokenizer",
        type=str,
        help="Name or path of the tokenizer, if not using the default tokenizer.",  # noqa: E501
    )
    parser.add_argument(
        "--tokenizer-mode",
        type=str,
        default="auto",
        help="""Tokenizer mode:\n
        - "auto" will use the tokenizer from `mistral_common` for Mistral models
        if available, otherwise it will use the "hf" tokenizer.\n
        - "hf" will use the fast tokenizer if available.\n
        - "slow" will always use the slow tokenizer.\n
        - "mistral" will always use the tokenizer from `mistral_common`.\n
        - "deepseek_v32" will always use the tokenizer from `deepseek_v32`.\n
        - Other custom values can be supported via plugins.""",
    )
    parser.add_argument("--use-beam-search", action="store_true")
    parser.add_argument(
        "--logprobs",
        type=int,
        default=None,
        help=(
            "Number of logprobs-per-token to compute & return as part of "
            "the request. If unspecified, then either (1) if beam search "
            "is disabled, no logprobs are computed & a single dummy "
            "logprob is returned for each token; or (2) if beam search "
            "is enabled 1 logprob per token is computed"
        ),
    )
    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 or gamma distribution "
        "to synthesize the request arrival times.",
    )
    parser.add_argument(
        "--burstiness",
        type=float,
        default=1.0,
        help="Burstiness factor of the request generation. "
        "Only take effect when request_rate is not inf. "
        "Default value is 1, which follows Poisson process. "
        "Otherwise, the request intervals follow a gamma distribution. "
        "A lower burstiness value (0 < burstiness < 1) results in more "
        "bursty requests. A higher burstiness value (burstiness > 1) "
        "results in a more uniform arrival of requests.",
    )
    parser.add_argument(
        "--trust-remote-code",
        action="store_true",
        help="Trust remote code from huggingface",
    )
    parser.add_argument(
        "--disable-tqdm",
        action="store_true",
        help="Specify to disable tqdm progress bar.",
    )
    parser.add_argument(
        "--num-warmups",
        type=int,
        default=0,
        help="Number of warmup requests.",
    )
    parser.add_argument(
        "--profile",
        action="store_true",
        help="Use vLLM Profiling. --profiler-config must be provided on the server.",
    )
    parser.add_argument(
        "--save-result",
        action="store_true",
        help="Specify to save benchmark results to a json file",
    )
    parser.add_argument(
        "--save-detailed",
        action="store_true",
        help="When saving the results, whether to include per request "
        "information such as response, error, ttfts, tpots, etc.",
    )
    parser.add_argument(
        "--append-result",
        action="store_true",
        help="Append the benchmark result to the existing json file.",
    )
    parser.add_argument(
        "--metadata",
        metavar="KEY=VALUE",
        nargs="*",
        help="Key-value pairs (e.g, --metadata version=0.3.3 tp=1) "
        "for metadata of this run to be saved in the result JSON file "
        "for record keeping purposes.",
    )
    parser.add_argument(
        "--result-dir",
        type=str,
        default=None,
        help="Specify directory to save benchmark json results."
        "If not specified, results are saved in the current directory.",
    )
    parser.add_argument(
        "--result-filename",
        type=str,
        default=None,
        help="Specify the filename to save benchmark json results."
        "If not specified, results will be saved in "
        "{label}-{args.request_rate}qps-{base_model_id}-{current_dt}.json"  # noqa
        " format.",
    )
    parser.add_argument(
        "--ignore-eos",
        action="store_true",
        help="Set ignore_eos flag when sending the benchmark request."
        "Warning: ignore_eos is not supported in deepspeed_mii and tgi.",
    )
    parser.add_argument(
        "--percentile-metrics",
        type=str,
        default=None,
        help="Comma-separated list of selected metrics to report percentiles. "
        "This argument specifies the metrics to report percentiles. "
        'Allowed metric names are "ttft", "tpot", "itl", "e2el". '
        'If not specified, defaults to "ttft,tpot,itl" for generative models '
        'and "e2el" for pooling models.',
    )
    parser.add_argument(
        "--metric-percentiles",
        type=str,
        default="99",
        help="Comma-separated list of percentiles for selected metrics. "
        'To report 25-th, 50-th, and 75-th percentiles, use "25,50,75". '
        'Default value is "99".'
        'Use "--percentile-metrics" to select metrics.',
    )
    parser.add_argument(
        "--goodput",
        nargs="+",
        required=False,
        help='Specify service level objectives for goodput as "KEY:VALUE" '
        "pairs, where the key is a metric name, and the value is in "
        'milliseconds. Multiple "KEY:VALUE" pairs can be provided, '
        "separated by spaces. Allowed request level metric names are "
        '"ttft", "tpot", "e2el". For more context on the definition of '
        "goodput, refer to DistServe paper: https://arxiv.org/pdf/2401.09670 "
        "and the blog: https://hao-ai-lab.github.io/blogs/distserve",
    )
    parser.add_argument(
        "--request-id-prefix",
        type=str,
        required=False,
        default=f"bench-{uuid.uuid4().hex[:8]}-",
        help="Specify the prefix of request id.",
    )

    sampling_group = parser.add_argument_group("sampling parameters")
    sampling_group.add_argument(
        "--top-p",
        type=float,
        default=None,
        help="Top-p sampling parameter. Only has effect on openai-compatible backends.",
    )
    sampling_group.add_argument(
        "--top-k",
        type=int,
        default=None,
        help="Top-k sampling parameter. Only has effect on openai-compatible backends.",
    )
    sampling_group.add_argument(
        "--min-p",
        type=float,
        default=None,
        help="Min-p sampling parameter. Only has effect on openai-compatible backends.",
    )
    sampling_group.add_argument(
        "--temperature",
        type=float,
        default=None,
        help="Temperature sampling parameter. Only has effect on "
        "openai-compatible backends. If not specified, default to greedy "
        "decoding (i.e. temperature==0.0).",
    )
    sampling_group.add_argument(
        "--frequency-penalty",
        type=float,
        default=None,
        help="Frequency penalty sampling parameter. Only has effect on "
        "openai-compatible backends.",
    )
    sampling_group.add_argument(
        "--presence-penalty",
        type=float,
        default=None,
        help="Presence penalty sampling parameter. Only has effect on "
        "openai-compatible backends.",
    )
    sampling_group.add_argument(
        "--repetition-penalty",
        type=float,
        default=None,
        help="Repetition penalty sampling parameter. Only has effect on "
        "openai-compatible backends.",
    )

    parser.add_argument(
        "--served-model-name",
        type=str,
        default=None,
        help="The model name used in the API. "
        "If not specified, the model name will be the "
        "same as the `--model` argument. ",
    )

    parser.add_argument(
        "--lora-modules",
        nargs="+",
        default=None,
        help="A subset of LoRA module names passed in when "
        "launching the server. For each request, the "
        "script chooses a LoRA module at random.",
    )

    parser.add_argument(
        "--ramp-up-strategy",
        type=str,
        default=None,
        choices=["linear", "exponential"],
        help="The ramp-up strategy. This would be used to "
        "ramp up the request rate from initial RPS to final "
        "RPS rate (specified by --ramp-up-start-rps and "
        "--ramp-up-end-rps.) over the duration of the benchmark.",
    )
    parser.add_argument(
        "--ramp-up-start-rps",
        type=int,
        default=None,
        help="The starting request rate for ramp-up (RPS). "
        "Needs to be specified when --ramp-up-strategy is used.",
    )
    parser.add_argument(
        "--ramp-up-end-rps",
        type=int,
        default=None,
        help="The ending request rate for ramp-up (RPS). "
        "Needs to be specified when --ramp-up-strategy is used.",
    )
    parser.add_argument(
        "--ready-check-timeout-sec",
        type=int,
        default=0,
        help="Maximum time to wait for the endpoint to become ready "
        "in seconds. Ready check will be skipped by default.",
    )

    parser.add_argument(
        "--extra-body",
        help="A JSON string representing extra body parameters to include "
        "in each request."
        'Example: \'{"chat_template_kwargs":{"enable_thinking":false}}\'',
        type=json.loads,
        default=None,
    )

async def benchmark(
    task_type: TaskType,
    endpoint_type: str,
    api_url: str,
    base_url: str,
    model_id: str,
    model_name: str,
    tokenizer: TokenizerLike,
    input_requests: list[SampleRequest],
    logprobs: int | None,
    request_rate: float,
    burstiness: float,
    disable_tqdm: bool,
    num_warmups: int,
    profile: bool,
    selected_percentile_metrics: list[str],
    selected_percentiles: list[float],
    ignore_eos: bool,
    goodput_config_dict: dict[str, float],
    max_concurrency: int | None,
    lora_modules: Iterable[str] | None,
    extra_headers: dict | None,
    extra_body: dict | None,
    ramp_up_strategy: Literal["linear", "exponential"] | None = None,
    ramp_up_start_rps: int | None = None,
    ramp_up_end_rps: int | None = None,
    ready_check_timeout_sec: int = 600,
):
    try:
        request_func = ASYNC_REQUEST_FUNCS[endpoint_type]
    except KeyError:
        raise ValueError(f"Unknown backend: {endpoint_type}") from None

    # Reuses connections across requests to reduce TLS handshake overhead.
    connector = aiohttp.TCPConnector(
        limit=max_concurrency or 0,
        limit_per_host=max_concurrency or 0,
        ttl_dns_cache=300,
        use_dns_cache=True,
        keepalive_timeout=60,
        enable_cleanup_closed=True,
        force_close=False,
        ssl=("https://" in api_url),
    )

    session = aiohttp.ClientSession(
        connector=connector,
        trust_env=True,
        timeout=aiohttp.ClientTimeout(total=6 * 60 * 60),
    )

    print("Starting initial single prompt test run...")
    test_prompt, test_prompt_len, test_output_len, test_mm_content = (
        input_requests[0].prompt,
        input_requests[0].prompt_len,
        input_requests[0].expected_output_len,
        input_requests[0].multi_modal_data,
    )

    assert (
        test_mm_content is None
        or isinstance(test_mm_content, dict)
        or (
            isinstance(test_mm_content, list)
            and all(isinstance(item, dict) for item in test_mm_content)
        )
    ), "multi_modal_data must be a dict or list[dict]"
    test_input = RequestFuncInput(
        model=model_id,
        model_name=model_name,
        prompt=test_prompt,
        api_url=api_url,
        prompt_len=test_prompt_len,
        output_len=test_output_len,
        logprobs=logprobs,
        multi_modal_content=test_mm_content,
        ignore_eos=ignore_eos,
        extra_headers=extra_headers,
        extra_body=extra_body,
    )

    if ready_check_timeout_sec > 0:
        test_output = await wait_for_endpoint(
            request_func,
            test_input,
            session,
            timeout_seconds=ready_check_timeout_sec,
        )
        if not test_output.success:
            raise ValueError(
                "Initial test run failed - Please make sure benchmark "
                "arguments are correctly specified. "
                f"Error: {test_output.error}"
            )
        else:
            print("Initial test run completed.")
    else:
        print("Skipping endpoint ready check.")

    if num_warmups > 0:
        print(f"Warming up with {num_warmups} requests...")
        warmup_pbar = None if disable_tqdm else tqdm(total=num_warmups)
        warmup_semaphore = (
            asyncio.Semaphore(max_concurrency)
            if max_concurrency
            else contextlib.nullcontext()
        )
        warmup_tasks = []

        async def warmup_limited_request_func():
            async with warmup_semaphore:
                return await request_func(
                    request_func_input=test_input, session=session, pbar=warmup_pbar
                )

        for _ in range(num_warmups):
            request_task = asyncio.create_task(warmup_limited_request_func())
            warmup_tasks.append(request_task)
        _ = await asyncio.gather(*warmup_tasks)

        if warmup_pbar is not None:
            warmup_pbar.close()
        print("Warmup run completed.")

    print("Starting main benchmark run...")

    if lora_modules:
        # For each input request, choose a LoRA module at random.
        lora_modules = iter(
            [random.choice(lora_modules) for _ in range(len(input_requests))]
        )

    if profile:
        print("Starting profiler...")
        profile_input = RequestFuncInput(
            model=model_id,
            model_name=model_name,
            prompt=test_prompt,
            api_url=base_url + "/start_profile",
            prompt_len=test_prompt_len,
            output_len=test_output_len,
            logprobs=logprobs,
            multi_modal_content=test_mm_content,
            ignore_eos=ignore_eos,
            extra_headers=extra_headers,
            extra_body=extra_body,
        )
        profile_output = await request_func(
            request_func_input=profile_input, session=session
        )
        if profile_output.success:
            print("Profiler started")

    distribution = "Poisson process" if burstiness == 1.0 else "Gamma distribution"

    if ramp_up_strategy is not None:
        print(f"Traffic ramp-up strategy: {ramp_up_strategy}.")
        print(
            f"Will increase RPS from {ramp_up_start_rps} to "
            f"{ramp_up_end_rps} RPS over the duration of the benchmark."
        )
    else:
        print(f"Traffic request rate: {request_rate}")

    print(f"Burstiness factor: {burstiness} ({distribution})")
    print(f"Maximum request concurrency: {max_concurrency}")

    spec_decode_metrics_before = await fetch_spec_decode_metrics(base_url, session)

    pbar = None if disable_tqdm else tqdm(total=len(input_requests))

    semaphore = (
        asyncio.Semaphore(max_concurrency)
        if max_concurrency
        else contextlib.nullcontext()
    )

    async def limited_request_func(request_func_input, session, pbar):
        async with semaphore:
            return await request_func(
                request_func_input=request_func_input, session=session, pbar=pbar
            )

    benchmark_start_time = time.perf_counter()
    tasks: list[asyncio.Task] = []

    rps_change_events = []
    last_int_rps = -1
    if ramp_up_strategy is not None and ramp_up_start_rps is not None:
        last_int_rps = ramp_up_start_rps
        rps_change_events.append(
            {
                "rps": last_int_rps,
                "timestamp": datetime.now().isoformat(),
            }
        )

    async for request, current_request_rate in get_request(
        input_requests,
        request_rate,
        burstiness,
        ramp_up_strategy,
        ramp_up_start_rps,
        ramp_up_end_rps,
    ):
        if ramp_up_strategy is not None:
            current_int_rps = int(current_request_rate)
            if current_int_rps > last_int_rps:
                timestamp = datetime.now().isoformat()
                for rps_val in range(last_int_rps + 1, current_int_rps + 1):
                    rps_change_events.append({"rps": rps_val, "timestamp": timestamp})
                last_int_rps = current_int_rps
        prompt, prompt_len, output_len, mm_content, request_id = (
            request.prompt,
            request.prompt_len,
            request.expected_output_len,
            request.multi_modal_data,
            request.request_id,
        )
        req_model_id, req_model_name = model_id, model_name
        if lora_modules:
            req_lora_module = next(lora_modules)
            req_model_id, req_model_name = req_lora_module, req_lora_module

        request_func_input = RequestFuncInput(
            model=req_model_id,
            model_name=req_model_name,
            prompt=prompt,
            api_url=api_url,
            prompt_len=prompt_len,
            output_len=output_len,
            logprobs=logprobs,
            multi_modal_content=mm_content,
            ignore_eos=ignore_eos,
            extra_headers=extra_headers,
            extra_body=extra_body,
            request_id=request_id,
        )
        tasks.append(
            asyncio.create_task(
                limited_request_func(
                    request_func_input=request_func_input, session=session, pbar=pbar
                )
            )
        )
    outputs: list[RequestFuncOutput] = await asyncio.gather(*tasks)

    if pbar is not None:
        pbar.close()

    benchmark_duration = time.perf_counter() - benchmark_start_time

    spec_decode_metrics_after = await fetch_spec_decode_metrics(base_url, session)
    spec_decode_stats: dict[str, Any] | None = None
    if spec_decode_metrics_before is not None and spec_decode_metrics_after is not None:
        delta_drafts = (
            spec_decode_metrics_after.num_drafts - spec_decode_metrics_before.num_drafts
        )
        delta_draft_tokens = (
            spec_decode_metrics_after.num_draft_tokens
            - spec_decode_metrics_before.num_draft_tokens
        )
        delta_accepted = (
            spec_decode_metrics_after.num_accepted_tokens
            - spec_decode_metrics_before.num_accepted_tokens
        )
        per_pos_rates: list[float] = []
        if delta_drafts > 0:
            positions = sorted(
                set(spec_decode_metrics_before.accepted_per_pos.keys())
                | set(spec_decode_metrics_after.accepted_per_pos.keys())
            )
            for pos in positions:
                before_val = spec_decode_metrics_before.accepted_per_pos.get(pos, 0)
                after_val = spec_decode_metrics_after.accepted_per_pos.get(
                    pos, before_val
                )
                delta_pos = after_val - before_val
                per_pos_rates.append(delta_pos / delta_drafts)

        if delta_draft_tokens > 0:
            acceptance_rate = (delta_accepted / delta_draft_tokens) * 100
            acceptance_length = (
                1 + delta_accepted / delta_drafts if delta_drafts > 0 else 0.0
            )
            spec_decode_stats = {
                "num_drafts": delta_drafts,
                "draft_tokens": delta_draft_tokens,
                "accepted_tokens": delta_accepted,
                "acceptance_rate": acceptance_rate,
                "acceptance_length": acceptance_length,
                "per_position_acceptance_rates": per_pos_rates,
            }

    if task_type == TaskType.GENERATION:
        metrics, actual_output_lens = calculate_metrics(
            input_requests=input_requests,
            outputs=outputs,
            dur_s=benchmark_duration,
            tokenizer=tokenizer,
            selected_percentiles=selected_percentiles,
            goodput_config_dict=goodput_config_dict,
        )
    else:
        metrics = calculate_metrics_for_embeddings(
            outputs=outputs,
            dur_s=benchmark_duration,
            selected_percentiles=selected_percentiles,
        )
        actual_output_lens = 0

    print("{s:{c}^{n}}".format(s=" Serving Benchmark Result ", n=50, c="="))
    print("{:<40} {:<10}".format("Successful requests:", metrics.completed))
    print("{:<40} {:<10}".format("Failed requests:", metrics.failed))
    if max_concurrency is not None:
        print("{:<40} {:<10}".format("Maximum request concurrency:", max_concurrency))
    if request_rate != float("inf"):
        print("{:<40} {:<10.2f}".format("Request rate configured (RPS):", request_rate))
    print("{:<40} {:<10.2f}".format("Benchmark duration (s):", benchmark_duration))
    print("{:<40} {:<10}".format("Total input tokens:", metrics.total_input))
    if isinstance(metrics, BenchmarkMetrics):
        print("{:<40} {:<10}".format("Total generated tokens:", metrics.total_output))
    print(
        "{:<40} {:<10.2f}".format(
            "Request throughput (req/s):", metrics.request_throughput
        )
    )
    if goodput_config_dict:
        print(
            "{:<40} {:<10.2f}".format(
                "Request goodput (req/s):", metrics.request_goodput
            )
        )
    if isinstance(metrics, BenchmarkMetrics):
        print(
            "{:<40} {:<10.2f}".format(
                "Output token throughput (tok/s):", metrics.output_throughput
            )
        )
        print(
            "{:<40} {:<10.2f}".format(
                "Peak output token throughput (tok/s):", metrics.max_output_tokens_per_s
            )
        )
        print(
            "{:<40} {:<10.2f}".format(
                "Peak concurrent requests:", metrics.max_concurrent_requests
            )
        )
    print(
        "{:<40} {:<10.2f}".format(
            "Total token throughput (tok/s):", metrics.total_token_throughput
        )
    )

    if isinstance(metrics, BenchmarkMetrics):
        result = {
            "duration": benchmark_duration,
            "completed": metrics.completed,
            "failed": metrics.failed,
            "total_input_tokens": metrics.total_input,
            "total_output_tokens": metrics.total_output,
            "request_throughput": metrics.request_throughput,
            "request_goodput": metrics.request_goodput if goodput_config_dict else None,
            "output_throughput": metrics.output_throughput,
            "total_token_throughput": metrics.total_token_throughput,
            "input_lens": [output.prompt_len for output in outputs],
            "output_lens": actual_output_lens,
            "ttfts": [output.ttft for output in outputs],
            "itls": [output.itl for output in outputs],
            "generated_texts": [output.generated_text for output in outputs],
            "errors": [output.error for output in outputs],
            "max_output_tokens_per_s": metrics.max_output_tokens_per_s,
            "max_concurrent_requests": metrics.max_concurrent_requests,
        }
    else:
        result = {
            "duration": benchmark_duration,
            "completed": metrics.completed,
            "total_input_tokens": metrics.total_input,
            "request_throughput": metrics.request_throughput,
            "total_token_throughput": metrics.total_token_throughput,
            "input_lens": [output.prompt_len for output in outputs],
            "errors": [output.error for output in outputs],
        }

    if rps_change_events:
        result["rps_change_events"] = rps_change_events

    if spec_decode_stats is not None:
        result["spec_decode_acceptance_rate"] = spec_decode_stats["acceptance_rate"]
        result["spec_decode_acceptance_length"] = spec_decode_stats["acceptance_length"]
        result["spec_decode_num_drafts"] = int(spec_decode_stats["num_drafts"])
        result["spec_decode_draft_tokens"] = int(spec_decode_stats["draft_tokens"])
        result["spec_decode_accepted_tokens"] = int(
            spec_decode_stats["accepted_tokens"]
        )
        result["spec_decode_per_position_acceptance_rates"] = spec_decode_stats.get(
            "per_position_acceptance_rates", []
        )

    def process_one_metric(
        # E.g., "ttft"
        metric_attribute_name: str,
        # E.g., "TTFT"
        metric_name: str,
        # E.g., "Time to First Token"
        metric_header: str,
    ):
        # This function prints and adds statistics of the specified
        # metric.
        if metric_attribute_name not in selected_percentile_metrics:
            return
        print("{s:{c}^{n}}".format(s=metric_header, n=50, c="-"))
        print(
            "{:<40} {:<10.2f}".format(
                f"Mean {metric_name} (ms):",
                getattr(metrics, f"mean_{metric_attribute_name}_ms"),
            )
        )
        print(
            "{:<40} {:<10.2f}".format(
                f"Median {metric_name} (ms):",
                getattr(metrics, f"median_{metric_attribute_name}_ms"),
            )
        )
        result[f"mean_{metric_attribute_name}_ms"] = getattr(
            metrics, f"mean_{metric_attribute_name}_ms"
        )
        result[f"median_{metric_attribute_name}_ms"] = getattr(
            metrics, f"median_{metric_attribute_name}_ms"
        )
        result[f"std_{metric_attribute_name}_ms"] = getattr(
            metrics, f"std_{metric_attribute_name}_ms"
        )
        for p, value in getattr(metrics, f"percentiles_{metric_attribute_name}_ms"):
            p_word = str(int(p)) if int(p) == p else str(p)
            print("{:<40} {:<10.2f}".format(f"P{p_word} {metric_name} (ms):", value))
            result[f"p{p_word}_{metric_attribute_name}_ms"] = value

    if task_type == TaskType.GENERATION:
        process_one_metric("ttft", "TTFT", "Time to First Token")
        process_one_metric("tpot", "TPOT", "Time per Output Token (excl. 1st token)")
        process_one_metric("itl", "ITL", "Inter-token Latency")
    process_one_metric("e2el", "E2EL", "End-to-end Latency")

    if spec_decode_stats is not None:
        print("{s:{c}^{n}}".format(s="Speculative Decoding", n=50, c="-"))
        print(
            "{:<40} {:<10.2f}".format(
                "Acceptance rate (%):", spec_decode_stats["acceptance_rate"]
            )
        )
        print(
            "{:<40} {:<10.2f}".format(
                "Acceptance length:", spec_decode_stats["acceptance_length"]
            )
        )
        print("{:<40} {:<10}".format("Drafts:", int(spec_decode_stats["num_drafts"])))
        print(
            "{:<40} {:<10}".format(
                "Draft tokens:", int(spec_decode_stats["draft_tokens"])
            )
        )
        print(
            "{:<40} {:<10}".format(
                "Accepted tokens:", int(spec_decode_stats["accepted_tokens"])
            )
        )
        per_pos = spec_decode_stats.get("per_position_acceptance_rates", [])
        if per_pos:
            print("Per-position acceptance (%):")
            for i, rate in enumerate(per_pos):
                print("{:<40} {:<10.2f}".format(f"  Position {i}:", rate * 100))

    print("=" * 50)

    if profile:
        print("Stopping profiler...")
        profile_input = RequestFuncInput(
            model=model_id,
            prompt=test_prompt,
            api_url=base_url + "/stop_profile",
            prompt_len=test_prompt_len,
            output_len=test_output_len,
            logprobs=logprobs,
        )
        profile_output = await request_func(
            request_func_input=profile_input, session=session
        )
        if profile_output.success:
            print("Profiler stopped")

    await session.close()
    return result