Files
nano-vllm/bench_offload.py
2026-01-07 04:25:06 +08:00

112 lines
4.5 KiB
Python

import os
import time
from random import randint, seed
from nanovllm import LLM, SamplingParams
def bench_decode(llm, num_seqs, input_len, output_len):
"""Benchmark decode performance"""
seed(0)
prompt_token_ids = [[randint(0, 10000) for _ in range(input_len)] for _ in range(num_seqs)]
sampling_params = SamplingParams(temperature=0.6, ignore_eos=True, max_tokens=output_len)
t = time.time()
llm.generate(prompt_token_ids, sampling_params, use_tqdm=False)
t = time.time() - t
# Calculate metrics
prefill_tokens = num_seqs * input_len
decode_tokens = num_seqs * output_len
# Approximate: assume prefill takes ~input_len/prefill_speed, rest is decode
# For more accurate measurement, we'd need internal timing
decode_throughput = decode_tokens / t # This includes prefill time, so it's a lower bound
print(f"[Decode] Input: {num_seqs}x{input_len}tok, Output: {decode_tokens}tok, Time: {t:.2f}s")
print(f" Throughput: {decode_throughput:.2f} tok/s (includes prefill overhead)")
def bench_prefill(llm, num_seqs, input_len):
"""Benchmark prefill performance"""
seed(0)
# Fixed length input, minimal output to focus on prefill
prompt_token_ids = [[randint(0, 10000) for _ in range(input_len)] for _ in range(num_seqs)]
sampling_params = SamplingParams(temperature=0.6, ignore_eos=True, max_tokens=1)
t = time.time()
llm.generate(prompt_token_ids, sampling_params, use_tqdm=False)
t = time.time() - t
total_input_tokens = num_seqs * input_len
throughput = total_input_tokens / t
print(f"[Prefill] Input: {total_input_tokens}tok ({num_seqs}x{input_len}), Time: {t:.2f}s, Throughput: {throughput:.2f}tok/s")
def main():
import argparse
from nanovllm.config import SparsePolicyType
parser = argparse.ArgumentParser(description="Benchmark CPU offload performance")
parser.add_argument("--enable-quest", action="store_true", help="Enable Quest sparse attention for decode")
parser.add_argument("--topk", type=int, default=16, help="Top-K blocks for Quest (default: 16)")
parser.add_argument("--threshold", type=int, default=4, help="Apply sparse only when blocks > threshold (default: 4)")
parser.add_argument("--input-len", type=int, default=None, help="Input length in tokens")
parser.add_argument("--output-len", type=int, default=64, help="Output length for decode benchmark (default: 64)")
parser.add_argument("--num-gpu-blocks", type=int, default=6, help="Number of GPU blocks (default: 6)")
parser.add_argument("--max-len", type=int, default=32*1024, help="Max model length (default: 32K)")
parser.add_argument("--bench-decode", action="store_true", help="Run decode benchmark (default: prefill only)")
parser.add_argument("--bench-all", action="store_true", help="Run both prefill and decode benchmarks")
args = parser.parse_args()
path = os.path.expanduser("~/models/Qwen3-4B-Instruct-2507/")
max_len = args.max_len
# Setup policy configuration
if args.enable_quest:
sparse_policy = SparsePolicyType.QUEST
print(f"\n[Quest Sparse Attention] topk={args.topk}, threshold={args.threshold}")
else:
sparse_policy = SparsePolicyType.FULL
print("\n[Full Attention] baseline (no sparse)")
print(f"[Config] max_len={max_len}, num_gpu_blocks={args.num_gpu_blocks}")
llm = LLM(
path,
enforce_eager=False,
max_model_len=max_len,
max_num_batched_tokens=max_len,
enable_cpu_offload=True,
num_gpu_blocks=args.num_gpu_blocks,
sparse_policy=sparse_policy,
sparse_topk_blocks=args.topk,
sparse_threshold_blocks=args.threshold,
)
# Warmup
print("\nWarming up...")
llm.generate(["Benchmark warmup: "], SamplingParams(max_tokens=10))
# Default input lengths
prefill_input_len = args.input_len if args.input_len else max_len - 1
decode_input_len = args.input_len if args.input_len else max_len - args.output_len
# Determine which benchmarks to run
run_prefill = not args.bench_decode or args.bench_all
run_decode = args.bench_decode or args.bench_all
if run_prefill:
print("\n" + "=" * 60)
print("Prefill Benchmark (CPU Offload)")
print("=" * 60)
bench_prefill(llm, num_seqs=1, input_len=prefill_input_len)
if run_decode:
print("\n" + "=" * 60)
print("Decode Benchmark (CPU Offload)")
print("=" * 60)
bench_decode(llm, num_seqs=1, input_len=decode_input_len, output_len=args.output_len)
if __name__ == "__main__":
main()