server-bench: make seed choice configurable

Author: JohannesGaessler

scripts/server-bench.py

@@ -32,11 +32,12 @@ def get_prompts_text(dataset_name: str, n_prompts: int) -> Optional[list[str]]:
     return ret
 
 
-def get_prompt_lengths_rng(n_prompts: int, prompt_length_min: int, prompt_length_max: int) -> list[int]:
+def get_prompt_lengths_rng(n_prompts: int, prompt_length_min: int, prompt_length_max: int, seed_offset: int) -> list[int]:
     assert n_prompts >= 0
     ret: list[int] = []
     for i in range(n_prompts):
-        random.seed(13 * i + 0)
+        if seed_offset >= 0:
+            random.seed(3 * (seed_offset + 1000 * i) + 0)
         ret.append(random.randint(prompt_length_min, prompt_length_max))
     return ret
 
@@ -46,12 +47,18 @@ def get_prompts_rng(prompt_lengths: list[int]) -> list[list[int]]:
 
 
 def get_server(path_server: str, path_log: Optional[str]) -> dict:
-    logger.info("Starting the llama.cpp server...")
-    hostname: str = os.environ.get("LLAMA_ARG_HOST", "127.0.0.1")
-    port: str = os.environ.get("LLAMA_ARG_PORT", "8080")
+    if os.environ.get("LLAMA_ARG_HOST") is None:
+        logger.info("LLAMA_ARG_HOST not explicitly set, using 127.0.0.1")
+        os.environ["LLAMA_ARG_HOST"] = "127.0.0.1"
+    if os.environ.get("LLAMA_ARG_PORT") is None:
+        logger.info("LLAMA_ARG_PORT not explicitly set, using 8080")
+        os.environ["LLAMA_ARG_PORT"] = "8080"
+    hostname: str = os.environ.get("LLAMA_ARG_HOST")
+    port: str = os.environ.get("LLAMA_ARG_PORT")
     address: str = f"http://{hostname}:{port}"
+    logger.info(f"Starting the llama.cpp server under {address}...")
 
-    fout = open(path_log, "w") if path_log is not None else subprocess.DEVNULL
+    fout = open(path_log.format(port=port), "w") if path_log is not None else subprocess.DEVNULL
     process = subprocess.Popen([path_server], stdout=fout, stderr=subprocess.STDOUT)
 
     n_failures: int = 0
@@ -128,7 +135,7 @@ def send_prompt(data: dict) -> tuple[float, list[float]]:
     return (t_submit, token_arrival_times)
 
 
-def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_prompts: int, n_predict: int, n_predict_min: int):
+def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_prompts: int, n_predict: int, n_predict_min: int, seed_offset: int):
     if os.environ.get("LLAMA_ARG_N_PARALLEL") is None:
         logger.info("LLAMA_ARG_N_PARALLEL not explicitly set, using 32")
         os.environ["LLAMA_ARG_N_PARALLEL"] = "32"
@@ -139,7 +146,7 @@ def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_p
         logger.info("LLAMA_ARG_FLASH_ATTN not explicitly set, using 'true'")
         os.environ["LLAMA_ARG_FLASH_ATTN"] = "true"
 
-    parallel: int = int(os.environ.get("LLAMA_ARG_N_PARALLEL", 1))
+    parallel: int = int(os.environ.get("LLAMA_ARG_N_PARALLEL"))
     prompts: Union[None, list[str], list[list[int]]] = get_prompts_text(prompt_source, n_prompts)
     synthetic_prompts: bool = prompts is None
     prompt_n = []
@@ -151,7 +158,7 @@ def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_p
         prompt_length_min: int = int(prompt_source_split[1])
         prompt_length_max: int = int(prompt_source_split[2])
         logger.info("Generating random prompts...")
-        prompt_n = get_prompt_lengths_rng(n_prompts, prompt_length_min, prompt_length_max)
+        prompt_n = get_prompt_lengths_rng(n_prompts, prompt_length_min, prompt_length_max, seed_offset)
         prompts = get_prompts_rng(prompt_n)
     else:
         n_predict_min = n_predict
@@ -176,10 +183,11 @@ def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_p
         data: list[dict] = []
 
         for i, p in enumerate(prompts):
-            random.seed(13 * i + 1)
+            if seed_offset >= 0:
+                random.seed(3 * (seed_offset + 1000 * i) + 1)
             data.append({
                 "session": session, "server_address": server_address, "prompt": p, "synthetic_prompt": synthetic_prompts,
-                "n_predict": random.randint(n_predict_min, n_predict), "seed": 13 * i + 2})
+                "n_predict": random.randint(n_predict_min, n_predict), "seed": 3 * (seed_offset + 1000 * i) + 2 if seed_offset >= 0 else -1})
 
         if not synthetic_prompts:
             logger.info("Getting the prompt lengths...")
@@ -251,7 +259,7 @@ def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_p
         "Results are printed to console and visualized as plots (saved to current working directory). "
         "To pass arguments such as the model path to the server, set the corresponding environment variables (see llama-server --help).")
     parser.add_argument("--path_server", type=str, default="llama-server", help="Path to the llama.cpp server binary")
-    parser.add_argument("--path_log", type=str, default="server-bench.log", help="Path to the model to use for the benchmark")
+    parser.add_argument("--path_log", type=str, default="server-bench-{port}.log", help="Path to the model to use for the benchmark")
     parser.add_argument(
         "--prompt_source", type=str, default="rng-1024-2048",
         help="How to get the prompts for the benchmark, either 'mmlu' for MMLU questions or "
@@ -261,5 +269,7 @@ def benchmark(path_server: str, path_log: Optional[str], prompt_source: str, n_p
     parser.add_argument(
         "--n_predict_min", type=int, default=1024,
         help="Min. number of tokens to predict per prompt (supported for synthetic prompts only)")
+    parser.add_argument("--seed_offset", type=int, default=0, help="Offset for determining the seeds fpr pseudorandom prompt/generation lengths. "
+                        "Corelations between seeds can occur when set >= 1000. Negative values mean no seed.")
     args = parser.parse_args()
     benchmark(**vars(args))