[BugFix][PD]: make example proxy usable with P2pNcclConnector (#26628)

Signed-off-by: PAN <1162953505@qq.com>

benchmarks/disagg_benchmarks/disagg_prefill_proxy_server.py

@@ -5,11 +5,12 @@ 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
-from rate_limiter import RateLimiter
-from request_queue import RequestQueue
 
 # Configure logging
 logging.basicConfig(level=logging.INFO)
@@ -24,26 +25,8 @@ def parse_args():
     parser.add_argument(
         "--timeout",
         type=float,
-        default=300,
-        help="Timeout for backend service requests in seconds (default: 300)",
-    )
-    parser.add_argument(
-        "--max-concurrent",
-        type=int,
-        default=100,
-        help="Maximum concurrent requests to backend services (default: 100)",
-    )
-    parser.add_argument(
-        "--queue-size",
-        type=int,
-        default=500,
-        help="Maximum number of requests in the queue (default: 500)",
-    )
-    parser.add_argument(
-        "--rate-limit",
-        type=int,
-        default=40,
-        help="Maximum requests per second (default: 40)",
+        default=6 * 60 * 60,
+        help="Timeout for backend service requests in seconds (default: 21600)",
     )
     parser.add_argument(
         "--port",
@@ -54,14 +37,32 @@ def parse_args():
     parser.add_argument(
         "--prefill-url",
         type=str,
-        default="http://localhost:8100/v1/completions",
-        help="Prefill service endpoint URL",
+        default="http://localhost:8100",
+        help="Prefill service base URL (protocol + host[:port])",
     )
     parser.add_argument(
         "--decode-url",
         type=str,
-        default="http://localhost:8200/v1/completions",
-        help="Decode service endpoint URL",
+        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()
@@ -73,70 +74,129 @@ def main():
 
     # Initialize configuration using command line parameters
     AIOHTTP_TIMEOUT = aiohttp.ClientTimeout(total=args.timeout)
-    MAX_CONCURRENT_REQUESTS = args.max_concurrent
-    REQUEST_QUEUE_SIZE = args.queue_size
-    RATE_LIMIT = args.rate_limit
     PREFILL_SERVICE_URL = args.prefill_url
     DECODE_SERVICE_URL = args.decode_url
     PORT = args.port
 
-    app = Quart(__name__)
+    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,
+    )
 
-    # Initialize the rate limiter and request queue
-    rate_limiter = RateLimiter(RATE_LIMIT)
-    request_queue = RequestQueue(MAX_CONCURRENT_REQUESTS, REQUEST_QUEUE_SIZE)
+    app = Quart(__name__)
 
-    # Attach the configuration object to the application instance
+    # 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,
-            "rate_limiter": rate_limiter,
-            "request_queue": request_queue,
             "PREFILL_SERVICE_URL": PREFILL_SERVICE_URL,
             "DECODE_SERVICE_URL": DECODE_SERVICE_URL,
+            "PREFILL_KV_ADDR": PREFILL_KV_ADDR,
+            "DECODE_KV_ADDR": DECODE_KV_ADDR,
         }
     )
 
-    # Start queue processing on app startup
-    @app.before_serving
-    async def startup():
-        """Start request processing task when app starts serving"""
-        asyncio.create_task(request_queue.process())
+    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)
 
-    async def forward_request(url, data):
-        """Forward request to backend service with rate limiting and error handling"""
-        headers = {"Authorization": f"Bearer {os.environ.get('OPENAI_API_KEY')}"}
+    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
 
-        # Use rate limiter as context manager
+    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 (
-            rate_limiter,
                 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 session.post(
-                    url=url, json=data, headers=headers
-                ) as response:
-                    if response.status == 200:
-                        # Stream response chunks
-                        async for chunk_bytes in response.content.iter_chunked(1024):
-                            yield chunk_bytes
-                    else:
-                        # Handle backend service errors
-                        error_text = await response.text()
+            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(
-                            "Backend service error: %s - %s",
-                            response.status,
-                            error_text,
-                        )
-                        yield b'{"error": "Backend service error"}'
-            except aiohttp.ClientError as e:
-                # Handle connection errors
-                logger.error("Connection error to %s: %s", url, str(e))
-                yield b'{"error": "Service unavailable"}'
+                        "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:
-                # Handle timeout errors
-                logger.error("Timeout connecting to %s", url)
-                yield b'{"error": "Service timeout"}'
+            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"""
@@ -146,13 +206,27 @@ def main():
             # 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
-            async for _ in forward_request(PREFILL_SERVICE_URL, prefill_request):
-                continue
+            # 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
-            generator = forward_request(DECODE_SERVICE_URL, original_request_data)
+            # 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
@@ -168,23 +242,10 @@ def main():
     @app.route("/v1/completions", methods=["POST"])
     async def handle_request():
         """Handle incoming API requests with concurrency and rate limiting"""
-        # Create task for request processing
-        task = asyncio.create_task(process_request())
-
-        # Enqueue request or reject if queue is full
-        if not await request_queue.enqueue(task):
-            return Response(
-                response=b'{"error": "Server busy, try again later"}',
-                status=503,
-                content_type="application/json",
-            )
-
         try:
-            # Return the response from the processing task
-            return await task
+            return await process_request()
         except asyncio.CancelledError:
-            # Handle task cancellation (timeout or queue full)
-            logger.warning("Request cancelled due to timeout or queue full")
+            logger.warning("Request cancelled")
             return Response(
                 response=b'{"error": "Request cancelled"}',
                 status=503,

examples/online_serving/disaggregated_prefill.sh

@@ -24,7 +24,14 @@ cleanup() {
     exit 0
 }
 
-export VLLM_HOST_IP=$(hostname -I | awk '{print $1}')
+
+if [[ -z "${VLLM_HOST_IP:-}" ]]; then
+    export VLLM_HOST_IP=127.0.0.1
+    echo "Using default VLLM_HOST_IP=127.0.0.1 (override by exporting VLLM_HOST_IP before running this script)"
+else
+    echo "Using provided VLLM_HOST_IP=${VLLM_HOST_IP}"
+fi
+
 
 # install quart first -- required for disagg prefill proxy serve
 if python3 -c "import quart" &> /dev/null; then
@@ -38,7 +45,7 @@ fi
 wait_for_server() {
   local port=$1
   timeout 1200 bash -c "
-    until curl -s localhost:${port}/v1/completions > /dev/null; do
+    until curl -i localhost:${port}/v1/models > /dev/null; do
       sleep 1
     done" && return 0 || return 1
 }
@@ -48,21 +55,23 @@ wait_for_server() {
 
 # prefilling instance, which is the KV producer
 CUDA_VISIBLE_DEVICES=0 vllm serve $MODEL_NAME \
+    --host 0.0.0.0 \
     --port 8100 \
     --max-model-len 100 \
     --gpu-memory-utilization 0.8 \
     --trust-remote-code \
     --kv-transfer-config \
-    '{"kv_connector":"P2pNcclConnector","kv_role":"kv_producer","kv_rank":0,"kv_parallel_size":2}' &
+    '{"kv_connector":"P2pNcclConnector","kv_role":"kv_producer","kv_rank":0,"kv_parallel_size":2,"kv_buffer_size":"1e9","kv_port":"14579","kv_connector_extra_config":{"proxy_ip":"'"$VLLM_HOST_IP"'","proxy_port":"30001","http_ip":"'"$VLLM_HOST_IP"'","http_port":"8100","send_type":"PUT_ASYNC"}}' &
 
 # decoding instance, which is the KV consumer  
 CUDA_VISIBLE_DEVICES=1 vllm serve $MODEL_NAME \
+    --host 0.0.0.0 \
     --port 8200 \
     --max-model-len 100 \
     --gpu-memory-utilization 0.8 \
     --trust-remote-code \
     --kv-transfer-config \
-    '{"kv_connector":"P2pNcclConnector","kv_role":"kv_consumer","kv_rank":1,"kv_parallel_size":2}' &
+    '{"kv_connector":"P2pNcclConnector","kv_role":"kv_consumer","kv_rank":1,"kv_parallel_size":2,"kv_buffer_size":"1e10","kv_port":"14580","kv_connector_extra_config":{"proxy_ip":"'"$VLLM_HOST_IP"'","proxy_port":"30001","http_ip":"'"$VLLM_HOST_IP"'","http_port":"8200","send_type":"PUT_ASYNC"}}' &
 
 # wait until prefill and decode instances are ready
 wait_for_server 8100