Sync from v0.13

This commit is contained in:
2026-01-19 10:38:50 +08:00
parent b2ef04d792
commit 5aef6c175a
3714 changed files with 854317 additions and 89342 deletions

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#!/bin/bash
# benchmark the overhead of disaggregated prefill.
# methodology:
# - send all request to prefill vLLM instance. It will buffer KV cache.
# - then send all request to decode instance.
# - The TTFT of decode instance is the overhead.
set -ex
kill_gpu_processes() {
# kill all processes on GPU.
pgrep pt_main_thread | xargs -r kill -9
pgrep python3 | xargs -r kill -9
# vLLM now names the process with VLLM prefix after https://github.com/vllm-project/vllm/pull/21445
pgrep VLLM | xargs -r kill -9
sleep 10
# remove vllm config file
rm -rf ~/.config/vllm
# Print the GPU memory usage
# so that we know if all GPU processes are killed.
gpu_memory_usage=$(nvidia-smi --query-gpu=memory.used --format=csv,noheader,nounits -i 0)
# The memory usage should be 0 MB.
echo "GPU 0 Memory Usage: $gpu_memory_usage MB"
}
wait_for_server() {
# wait for vllm server to start
# return 1 if vllm server crashes
local port=$1
timeout 1200 bash -c "
until curl -s localhost:${port}/v1/completions > /dev/null; do
sleep 1
done" && return 0 || return 1
}
benchmark() {
export VLLM_LOGGING_LEVEL=DEBUG
export VLLM_HOST_IP=$(hostname -I | awk '{print $1}')
# compare chunked prefill with disaggregated prefill
results_folder="./results"
model="meta-llama/Meta-Llama-3.1-8B-Instruct"
dataset_name="sonnet"
dataset_path="../sonnet_4x.txt"
num_prompts=10
qps=$1
prefix_len=50
input_len=2048
output_len=$2
CUDA_VISIBLE_DEVICES=0 vllm serve $model \
--port 8100 \
--max-model-len 10000 \
--gpu-memory-utilization 0.6 \
--kv-transfer-config \
'{"kv_connector":"P2pNcclConnector","kv_role":"kv_producer","kv_rank":0,"kv_parallel_size":2,"kv_buffer_size":5e9}' &
CUDA_VISIBLE_DEVICES=1 vllm serve $model \
--port 8200 \
--max-model-len 10000 \
--gpu-memory-utilization 0.6 \
--kv-transfer-config \
'{"kv_connector":"P2pNcclConnector","kv_role":"kv_consumer","kv_rank":1,"kv_parallel_size":2,"kv_buffer_size":5e9}' &
wait_for_server 8100
wait_for_server 8200
# let the prefill instance finish prefill
vllm bench serve \
--backend vllm \
--model $model \
--dataset-name $dataset_name \
--dataset-path $dataset_path \
--sonnet-input-len $input_len \
--sonnet-output-len "$output_len" \
--sonnet-prefix-len $prefix_len \
--num-prompts $num_prompts \
--port 8100 \
--save-result \
--result-dir $results_folder \
--result-filename disagg_prefill_tp1.json \
--request-rate "inf"
# send the request to decode.
# The TTFT of this command will be the overhead of disagg prefill impl.
vllm bench serve \
--backend vllm \
--model $model \
--dataset-name $dataset_name \
--dataset-path $dataset_path \
--sonnet-input-len $input_len \
--sonnet-output-len "$output_len" \
--sonnet-prefix-len $prefix_len \
--num-prompts $num_prompts \
--port 8200 \
--save-result \
--result-dir $results_folder \
--result-filename disagg_prefill_tp1_overhead.json \
--request-rate "$qps"
kill_gpu_processes
}
main() {
(which wget && which curl) || (apt-get update && apt-get install -y wget curl)
(which jq) || (apt-get -y install jq)
(which socat) || (apt-get -y install socat)
pip install quart httpx datasets
cd "$(dirname "$0")"
cd ..
# create sonnet-4x.txt
echo "" > sonnet_4x.txt
for _ in {1..4}
do
cat sonnet.txt >> sonnet_4x.txt
done
cd disagg_benchmarks
rm -rf results
mkdir results
default_qps=1
default_output_len=1
benchmark $default_qps $default_output_len
}
main "$@"

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#!/bin/bash
# Requirement: 2x GPUs.
# Model: meta-llama/Meta-Llama-3.1-8B-Instruct
# Query: 1024 input tokens, 6 output tokens, QPS 2/4/6/8, 100 requests
# Resource: 2x GPU
# Approaches:
# 2. Chunked prefill: 2 vllm instance with tp=4, equivalent to 1 tp=4 instance with QPS 4
# 3. Disaggregated prefill: 1 prefilling instance and 1 decoding instance
# Prefilling instance: max_output_token=1
# Decoding instance: force the input tokens be the same across requests to bypass prefilling
set -ex
kill_gpu_processes() {
# kill all processes on GPU.
pgrep pt_main_thread | xargs -r kill -9
pgrep python3 | xargs -r kill -9
# vLLM now names the process with VLLM prefix after https://github.com/vllm-project/vllm/pull/21445
pgrep VLLM | xargs -r kill -9
for port in 8000 8100 8200; do lsof -t -i:$port | xargs -r kill -9; done
sleep 1
}
wait_for_server() {
# wait for vllm server to start
# return 1 if vllm server crashes
local port=$1
timeout 1200 bash -c "
until curl -s localhost:${port}/v1/completions > /dev/null; do
sleep 1
done" && return 0 || return 1
}
launch_chunked_prefill() {
model="meta-llama/Meta-Llama-3.1-8B-Instruct"
# disagg prefill
CUDA_VISIBLE_DEVICES=0 vllm serve $model \
--port 8100 \
--max-model-len 10000 \
--enable-chunked-prefill \
--gpu-memory-utilization 0.6 &
CUDA_VISIBLE_DEVICES=1 vllm serve $model \
--port 8200 \
--max-model-len 10000 \
--enable-chunked-prefill \
--gpu-memory-utilization 0.6 &
wait_for_server 8100
wait_for_server 8200
python3 round_robin_proxy.py &
sleep 1
}
launch_disagg_prefill() {
model="meta-llama/Meta-Llama-3.1-8B-Instruct"
# disagg prefill
CUDA_VISIBLE_DEVICES=0 vllm serve $model \
--port 8100 \
--max-model-len 10000 \
--gpu-memory-utilization 0.6 \
--kv-transfer-config \
'{"kv_connector":"P2pNcclConnector","kv_role":"kv_producer","kv_rank":0,"kv_parallel_size":2,"kv_buffer_size":5e9}' &
CUDA_VISIBLE_DEVICES=1 vllm serve $model \
--port 8200 \
--max-model-len 10000 \
--gpu-memory-utilization 0.6 \
--kv-transfer-config \
'{"kv_connector":"P2pNcclConnector","kv_role":"kv_consumer","kv_rank":1,"kv_parallel_size":2,"kv_buffer_size":5e9}' &
wait_for_server 8100
wait_for_server 8200
python3 disagg_prefill_proxy_server.py &
sleep 1
}
benchmark() {
results_folder="./results"
model="meta-llama/Meta-Llama-3.1-8B-Instruct"
dataset_name="sonnet"
dataset_path="../sonnet_4x.txt"
num_prompts=100
qps=$1
prefix_len=50
input_len=1024
output_len=$2
tag=$3
vllm bench serve \
--backend vllm \
--model $model \
--dataset-name $dataset_name \
--dataset-path $dataset_path \
--sonnet-input-len $input_len \
--sonnet-output-len "$output_len" \
--sonnet-prefix-len $prefix_len \
--num-prompts $num_prompts \
--port 8000 \
--save-result \
--result-dir $results_folder \
--result-filename "$tag"-qps-"$qps".json \
--request-rate "$qps"
sleep 2
}
main() {
(which wget && which curl) || (apt-get update && apt-get install -y wget curl)
(which jq) || (apt-get -y install jq)
(which socat) || (apt-get -y install socat)
(which lsof) || (apt-get -y install lsof)
pip install quart httpx matplotlib aiohttp datasets
cd "$(dirname "$0")"
cd ..
# create sonnet-4x.txt so that we can sample 2048 tokens for input
echo "" > sonnet_4x.txt
for _ in {1..4}
do
cat sonnet.txt >> sonnet_4x.txt
done
cd disagg_benchmarks
rm -rf results
mkdir results
default_output_len=6
export VLLM_HOST_IP=$(hostname -I | awk '{print $1}')
launch_chunked_prefill
for qps in 2 4 6 8; do
benchmark $qps $default_output_len chunked_prefill
done
kill_gpu_processes
launch_disagg_prefill
for qps in 2 4 6 8; do
benchmark $qps $default_output_len disagg_prefill
done
kill_gpu_processes
python3 visualize_benchmark_results.py
}
main "$@"

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import argparse
import asyncio
import logging
import os
import time
import uuid
from urllib.parse import urlparse
import aiohttp
from quart import Quart, Response, make_response, request
# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
def parse_args():
"""parse command line arguments"""
parser = argparse.ArgumentParser(description="vLLM P/D disaggregation proxy server")
# Add args
parser.add_argument(
"--timeout",
type=float,
default=6 * 60 * 60,
help="Timeout for backend service requests in seconds (default: 21600)",
)
parser.add_argument(
"--port",
type=int,
default=8000,
help="Port to run the server on (default: 8000)",
)
parser.add_argument(
"--prefill-url",
type=str,
default="http://localhost:8100",
help="Prefill service base URL (protocol + host[:port])",
)
parser.add_argument(
"--decode-url",
type=str,
default="http://localhost:8200",
help="Decode service base URL (protocol + host[:port])",
)
parser.add_argument(
"--kv-host",
type=str,
default="localhost",
help="Hostname or IP used by KV transfer (default: localhost)",
)
parser.add_argument(
"--prefill-kv-port",
type=int,
default=14579,
help="Prefill KV port (default: 14579)",
)
parser.add_argument(
"--decode-kv-port",
type=int,
default=14580,
help="Decode KV port (default: 14580)",
)
return parser.parse_args()
def main():
"""parse command line arguments"""
args = parse_args()
# Initialize configuration using command line parameters
AIOHTTP_TIMEOUT = aiohttp.ClientTimeout(total=args.timeout)
PREFILL_SERVICE_URL = args.prefill_url
DECODE_SERVICE_URL = args.decode_url
PORT = args.port
PREFILL_KV_ADDR = f"{args.kv_host}:{args.prefill_kv_port}"
DECODE_KV_ADDR = f"{args.kv_host}:{args.decode_kv_port}"
logger.info(
"Proxy resolved KV addresses -> prefill: %s, decode: %s",
PREFILL_KV_ADDR,
DECODE_KV_ADDR,
)
app = Quart(__name__)
# Attach the configuration object to the application instance so helper
# coroutines can read the resolved backend URLs and timeouts without using
# globals.
app.config.update(
{
"AIOHTTP_TIMEOUT": AIOHTTP_TIMEOUT,
"PREFILL_SERVICE_URL": PREFILL_SERVICE_URL,
"DECODE_SERVICE_URL": DECODE_SERVICE_URL,
"PREFILL_KV_ADDR": PREFILL_KV_ADDR,
"DECODE_KV_ADDR": DECODE_KV_ADDR,
}
)
def _normalize_base_url(url: str) -> str:
"""Remove any trailing slash so path joins behave predictably."""
return url.rstrip("/")
def _get_host_port(url: str) -> str:
"""Return the hostname:port portion for logging and KV headers."""
parsed = urlparse(url)
host = parsed.hostname or "localhost"
port = parsed.port
if port is None:
port = 80 if parsed.scheme == "http" else 443
return f"{host}:{port}"
PREFILL_BASE = _normalize_base_url(PREFILL_SERVICE_URL)
DECODE_BASE = _normalize_base_url(DECODE_SERVICE_URL)
KV_TARGET = _get_host_port(DECODE_SERVICE_URL)
def _build_headers(request_id: str) -> dict[str, str]:
"""Construct the headers expected by vLLM's P2P disagg connector."""
headers: dict[str, str] = {"X-Request-Id": request_id, "X-KV-Target": KV_TARGET}
api_key = os.environ.get("OPENAI_API_KEY")
if api_key:
headers["Authorization"] = f"Bearer {api_key}"
return headers
async def _run_prefill(
request_path: str,
payload: dict,
headers: dict[str, str],
request_id: str,
):
url = f"{PREFILL_BASE}{request_path}"
start_ts = time.perf_counter()
logger.info("[prefill] start request_id=%s url=%s", request_id, url)
try:
async with (
aiohttp.ClientSession(timeout=AIOHTTP_TIMEOUT) as session,
session.post(url=url, json=payload, headers=headers) as resp,
):
if resp.status != 200:
error_text = await resp.text()
raise RuntimeError(
f"Prefill backend error {resp.status}: {error_text}"
)
await resp.read()
logger.info(
"[prefill] done request_id=%s status=%s elapsed=%.2fs",
request_id,
resp.status,
time.perf_counter() - start_ts,
)
except asyncio.TimeoutError as exc:
raise RuntimeError(f"Prefill service timeout at {url}") from exc
except aiohttp.ClientError as exc:
raise RuntimeError(f"Prefill service unavailable at {url}") from exc
async def _stream_decode(
request_path: str,
payload: dict,
headers: dict[str, str],
request_id: str,
):
url = f"{DECODE_BASE}{request_path}"
# Stream tokens from the decode service once the prefill stage has
# materialized KV caches on the target workers.
logger.info("[decode] start request_id=%s url=%s", request_id, url)
try:
async with (
aiohttp.ClientSession(timeout=AIOHTTP_TIMEOUT) as session,
session.post(url=url, json=payload, headers=headers) as resp,
):
if resp.status != 200:
error_text = await resp.text()
logger.error(
"Decode backend error %s - %s", resp.status, error_text
)
err_msg = (
'{"error": "Decode backend error ' + str(resp.status) + '"}'
)
yield err_msg.encode()
return
logger.info(
"[decode] streaming response request_id=%s status=%s",
request_id,
resp.status,
)
async for chunk_bytes in resp.content.iter_chunked(1024):
yield chunk_bytes
logger.info("[decode] finished streaming request_id=%s", request_id)
except asyncio.TimeoutError:
logger.error("Decode service timeout at %s", url)
yield b'{"error": "Decode service timeout"}'
except aiohttp.ClientError as exc:
logger.error("Decode service error at %s: %s", url, exc)
yield b'{"error": "Decode service unavailable"}'
async def process_request():
"""Process a single request through prefill and decode stages"""
try:
original_request_data = await request.get_json()
# Create prefill request (max_tokens=1)
prefill_request = original_request_data.copy()
prefill_request["max_tokens"] = 1
if "max_completion_tokens" in prefill_request:
prefill_request["max_completion_tokens"] = 1
# Execute prefill stage
# The request id encodes both KV socket addresses so the backend can
# shuttle tensors directly via NCCL once the prefill response
# completes.
request_id = (
f"___prefill_addr_{PREFILL_KV_ADDR}___decode_addr_"
f"{DECODE_KV_ADDR}_{uuid.uuid4().hex}"
)
headers = _build_headers(request_id)
await _run_prefill(request.path, prefill_request, headers, request_id)
# Execute decode stage and stream response
# Pass the unmodified user request so the decode phase can continue
# sampling with the already-populated KV cache.
generator = _stream_decode(
request.path, original_request_data, headers, request_id
)
response = await make_response(generator)
response.timeout = None # Disable timeout for streaming response
return response
except Exception:
logger.exception("Error processing request")
return Response(
response=b'{"error": "Internal server error"}',
status=500,
content_type="application/json",
)
@app.route("/v1/completions", methods=["POST"])
async def handle_request():
"""Handle incoming API requests with concurrency and rate limiting"""
try:
return await process_request()
except asyncio.CancelledError:
logger.warning("Request cancelled")
return Response(
response=b'{"error": "Request cancelled"}',
status=503,
content_type="application/json",
)
# Start the Quart server with host can be set to 0.0.0.0
app.run(port=PORT)
if __name__ == "__main__":
main()

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import asyncio
import time
class RateLimiter:
"""Token bucket rate limiter implementation"""
def __init__(self, rate_limit):
self.rate_limit = rate_limit # Requests per second
self.num_available_tokens = rate_limit # Available tokens
self.last_refill = time.monotonic() # Last token refill time
self.lock = asyncio.Lock() # Synchronization lock
async def acquire(self):
"""Acquire a token from the rate limiter"""
while True:
async with self.lock:
current_time = time.monotonic()
elapsed = current_time - self.last_refill
# Refill num_available_tokens if more than 1 second has passed
if elapsed > 1.0:
self.num_available_tokens = self.rate_limit
self.last_refill = current_time
# Check if num_available_tokens are available
if self.num_available_tokens > 0:
self.num_available_tokens -= 1
return True
# Calculate wait time if no num_available_tokens available
wait_time = 1.0 - elapsed
await asyncio.sleep(wait_time)
async def __aenter__(self):
"""Enter async context manager - acquire token"""
await self.acquire()
return self
async def __aexit__(self, exc_type, exc_value, traceback):
"""Exit async context manager - no cleanup needed"""
pass

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import asyncio
from collections import deque
class RequestQueue:
"""Request queue manager with concurrency control"""
def __init__(self, max_concurrent, max_queue_size):
# Maximum concurrent requests
self.max_concurrent = max_concurrent
self.max_queue_size = max_queue_size # Maximum queue size
# Concurrency control
self.semaphore = asyncio.Semaphore(max_concurrent)
self.queue = deque() # Request queue
self.queue_size = 0 # Current queue size
self.lock = asyncio.Lock() # Sync queue Lock
async def enqueue(self, task):
"""Add a request task to the queue"""
async with self.lock:
if self.queue_size >= self.max_queue_size:
return False
self.queue.append(task)
self.queue_size += 1
return True
async def process(self):
"""Process queued requests using semaphore for concurrency control"""
while True:
if self.queue:
async with self.semaphore, self.lock:
task = self.queue.popleft()
self.queue_size -= 1
await task
await asyncio.sleep(0.01) # Yield control to event loop

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import asyncio
import itertools
import aiohttp
from aiohttp import web
class RoundRobinProxy:
def __init__(self, target_ports):
self.target_ports = target_ports
self.port_cycle = itertools.cycle(self.target_ports)
async def handle_request(self, request):
target_port = next(self.port_cycle)
target_url = f"http://localhost:{target_port}{request.path_qs}"
async with aiohttp.ClientSession() as session:
try:
# Forward the request
async with session.request(
method=request.method,
url=target_url,
headers=request.headers,
data=request.content,
) as response:
# Start sending the response
resp = web.StreamResponse(
status=response.status, headers=response.headers
)
await resp.prepare(request)
# Stream the response content
async for chunk in response.content.iter_any():
await resp.write(chunk)
await resp.write_eof()
return resp
except Exception as e:
return web.Response(text=f"Error: {str(e)}", status=500)
async def main():
proxy = RoundRobinProxy([8100, 8200])
app = web.Application()
app.router.add_route("*", "/{path:.*}", proxy.handle_request)
runner = web.AppRunner(app)
await runner.setup()
site = web.TCPSite(runner, "localhost", 8000)
await site.start()
print("Proxy server started on http://localhost:8000")
# Keep the server running
await asyncio.Event().wait()
if __name__ == "__main__":
asyncio.run(main())

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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import json
import matplotlib.pyplot as plt
import pandas as pd
if __name__ == "__main__":
data = []
for name in ["disagg_prefill", "chunked_prefill"]:
for qps in [2, 4, 6, 8]:
with open(f"results/{name}-qps-{qps}.json") as f:
x = json.load(f)
x["name"] = name
x["qps"] = qps
data.append(x)
df = pd.DataFrame.from_dict(data)
dis_df = df[df["name"] == "disagg_prefill"]
chu_df = df[df["name"] == "chunked_prefill"]
plt.style.use("bmh")
plt.rcParams["font.size"] = 20
for key in [
"mean_ttft_ms",
"median_ttft_ms",
"p99_ttft_ms",
"mean_itl_ms",
"median_itl_ms",
"p99_itl_ms",
]:
fig, ax = plt.subplots(figsize=(11, 7))
plt.plot(
dis_df["qps"], dis_df[key], label="disagg_prefill", marker="o", linewidth=4
)
plt.plot(
chu_df["qps"], chu_df[key], label="chunked_prefill", marker="o", linewidth=4
)
ax.legend()
ax.set_xlabel("QPS")
ax.set_ylabel(key)
ax.set_ylim(bottom=0)
fig.savefig(f"results/{key}.png")
plt.close(fig)