diff --git a/benchmarks/benchmark_serving.py b/benchmarks/benchmark_serving.py index ff06622628219..bdb8ea8e2a5dc 100644 --- a/benchmarks/benchmark_serving.py +++ b/benchmarks/benchmark_serving.py @@ -297,8 +297,33 @@ def sample_random_requests( async def get_request( input_requests: List[Tuple[str, int, int]], request_rate: float, + burstiness: float = 1.0, ) -> AsyncGenerator[Tuple[str, int, int], None]: + """ + Asynchronously generates requests at a specified rate + with OPTIONAL burstiness. + + Args: + input_requests: + A list of input requests, each represented as a tuple. + request_rate: + The rate at which requests are generated (requests/s). + burstiness (optional): + The burstiness factor of the request generation. + Only takes effect when request_rate is not inf. + Default value is 1, which follows a Poisson process. + Otherwise, the request intervals follow a gamma distribution. + A lower burstiness value (0 < burstiness < 1) results + in more bursty requests, while a higher burstiness value + (burstiness > 1) results in a more uniform arrival of requests. + """ input_requests = iter(input_requests) + + # Calculate scale parameter theta to maintain the desired request_rate. + assert burstiness > 0, ( + f"A positive burstiness factor is expected, but given {burstiness}.") + theta = 1.0 / (request_rate * burstiness) + for request in input_requests: yield request @@ -306,8 +331,9 @@ async def get_request( # 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) + # Sample the request interval from the gamma distribution. + # If burstiness is 1, it follows exponential distribution. + interval = np.random.gamma(shape=burstiness, scale=theta) # The next request will be sent after the interval. await asyncio.sleep(interval) @@ -426,6 +452,7 @@ async def benchmark( logprobs: Optional[int], best_of: int, request_rate: float, + burstiness: float, disable_tqdm: bool, profile: bool, selected_percentile_metrics: List[str], @@ -480,7 +507,13 @@ async def benchmark( if profile_output.success: print("Profiler started") + if burstiness == 1.0: + distribution = "Poisson process" + else: + distribution = "Gamma distribution" + print(f"Traffic request rate: {request_rate}") + print(f"Burstiness factor: {burstiness} ({distribution})") print(f"Maximum request concurrency: {max_concurrency}") pbar = None if disable_tqdm else tqdm(total=len(input_requests)) @@ -502,7 +535,7 @@ async def limited_request_func(request_func_input, pbar): benchmark_start_time = time.perf_counter() tasks: List[asyncio.Task] = [] - async for request in get_request(input_requests, request_rate): + async for request in get_request(input_requests, request_rate, burstiness): prompt, prompt_len, output_len, mm_content = request request_func_input = RequestFuncInput(model=model_id, prompt=prompt, @@ -769,6 +802,7 @@ def main(args: argparse.Namespace): logprobs=args.logprobs, best_of=args.best_of, request_rate=args.request_rate, + burstiness=args.burstiness, disable_tqdm=args.disable_tqdm, profile=args.profile, selected_percentile_metrics=args.percentile_metrics.split(","), @@ -807,6 +841,7 @@ def main(args: argparse.Namespace): # Traffic result_json["request_rate"] = ( args.request_rate if args.request_rate < float("inf") else "inf") + result_json["burstiness"] = args.burstiness result_json["max_concurrency"] = args.max_concurrency # Merge with benchmark result @@ -922,8 +957,20 @@ def main(args: argparse.Namespace): 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.", + "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("--seed", type=int, default=0) parser.add_argument(