[V1][P/D] An native implementation of xPyD based on P2P NCCL (#18242)

Signed-off-by: Abatom <abzhonghua@gmail.com>

Author: Abatom

docs/design/v1/p2p_nccl_connector.md

@@ -0,0 +1,154 @@
+# SPDX-License-Identifier: Apache-2.0
+
+import os
+import socket
+import threading
+import uuid
+
+import aiohttp
+import msgpack
+import zmq
+from quart import Quart, make_response, request
+
+count = 0
+prefill_instances: dict[str, str] = {}  # http_address: zmq_address
+decode_instances: dict[str, str] = {}  # http_address: zmq_address
+
+prefill_cv = threading.Condition()
+decode_cv = threading.Condition()
+
+
+def _listen_for_register(poller, router_socket):
+    while True:
+        socks = dict(poller.poll())
+        if router_socket in socks:
+            remote_address, message = router_socket.recv_multipart()
+            # data: {"type": "P", "http_address": "ip:port",
+            #        "zmq_address": "ip:port"}
+            data = msgpack.loads(message)
+            if data["type"] == "P":
+                global prefill_instances
+                global prefill_cv
+                with prefill_cv:
+                    prefill_instances[data["http_address"]] = data["zmq_address"]
+            elif data["type"] == "D":
+                global decode_instances
+                global decode_cv
+                with decode_cv:
+                    decode_instances[data["http_address"]] = data["zmq_address"]
+            else:
+                print(
+                    "Unexpected, Received message from %s, data: %s",
+                    remote_address,
+                    data,
+                )
+
+
+def start_service_discovery(hostname, port):
+    if not hostname:
+        hostname = socket.gethostname()
+    if port == 0:
+        raise ValueError("Port cannot be 0")
+
+    context = zmq.Context()
+    router_socket = context.socket(zmq.ROUTER)
+    router_socket.bind(f"tcp://{hostname}:{port}")
+
+    poller = zmq.Poller()
+    poller.register(router_socket, zmq.POLLIN)
+
+    _listener_thread = threading.Thread(
+        target=_listen_for_register, args=[poller, router_socket], daemon=True
+    )
+    _listener_thread.start()
+    return _listener_thread
+
+
+AIOHTTP_TIMEOUT = aiohttp.ClientTimeout(total=6 * 60 * 60)
+
+app = Quart(__name__)
+
+
+def random_uuid() -> str:
+    return str(uuid.uuid4().hex)
+
+
+async def forward_request(url, data, request_id):
+    async with aiohttp.ClientSession(timeout=AIOHTTP_TIMEOUT) as session:
+        headers = {
+            "Authorization": f"Bearer {os.environ.get('OPENAI_API_KEY')}",
+            "X-Request-Id": request_id,
+        }
+        async with session.post(url=url, json=data, headers=headers) as response:
+            if response.status == 200:
+                if True:
+                    async for chunk_bytes in response.content.iter_chunked(1024):
+                        yield chunk_bytes
+                else:
+                    content = await response.read()
+                    yield content
+
+
+@app.route("/v1/completions", methods=["POST"])
+async def handle_request():
+    try:
+        original_request_data = await request.get_json()
+
+        prefill_request = original_request_data.copy()
+        # change max_tokens = 1 to let it only do prefill
+        prefill_request["max_tokens"] = 1
+
+        global count
+        global prefill_instances
+        global prefill_cv
+        with prefill_cv:
+            prefill_list = list(prefill_instances.items())
+            prefill_addr, prefill_zmq_addr = prefill_list[count % len(prefill_list)]
+
+        global decode_instances
+        global decode_cv
+        with decode_cv:
+            decode_list = list(decode_instances.items())
+            decode_addr, decode_zmq_addr = decode_list[count % len(decode_list)]
+
+        print(
+            f"handle_request count: {count}, [HTTP:{prefill_addr}, "
+            f"ZMQ:{prefill_zmq_addr}] 👉 [HTTP:{decode_addr}, "
+            f"ZMQ:{decode_zmq_addr}]"
+        )
+        count += 1
+
+        request_id = (
+            f"___prefill_addr_{prefill_zmq_addr}___decode_addr_"
+            f"{decode_zmq_addr}_{random_uuid()}"
+        )
+
+        # finish prefill
+        async for _ in forward_request(
+            f"http://{prefill_addr}/v1/completions", prefill_request, request_id
+        ):
+            continue
+
+        # return decode
+        generator = forward_request(
+            f"http://{decode_addr}/v1/completions", original_request_data, request_id
+        )
+        response = await make_response(generator)
+        response.timeout = None
+
+        return response
+
+    except Exception as e:
+        import sys
+        import traceback
+
+        exc_info = sys.exc_info()
+        print("Error occurred in disagg prefill proxy server")
+        print(e)
+        print("".join(traceback.format_exception(*exc_info)))
+
+
+if __name__ == "__main__":
+    t = start_service_discovery("0.0.0.0", 30001)
+    app.run(host="0.0.0.0", port=10001)
+    t.join()

examples/online_serving/disagg_xpyd/disagg_prefill_proxy_xpyd.py

@@ -272,6 +272,14 @@ def ncclGetUniqueId(self) -> ncclUniqueId:
             ctypes.byref(unique_id)))
         return unique_id
 
+    def unique_id_from_bytes(self, data: bytes) -> ncclUniqueId:
+        if len(data) != 128:
+            raise ValueError(
+                f"Expected 128 bytes for ncclUniqueId, got {len(data)} bytes")
+        unique_id = ncclUniqueId()
+        ctypes.memmove(ctypes.addressof(unique_id.internal), data, 128)
+        return unique_id
+
     def ncclCommInitRank(self, world_size: int, unique_id: ncclUniqueId,
                          rank: int) -> ncclComm_t:
         comm = ncclComm_t()

vllm/distributed/device_communicators/pynccl_wrapper.py

@@ -112,6 +112,11 @@ def create_connector_v1(
     "vllm.distributed.kv_transfer.kv_connector.v1.shared_storage_connector",
     "SharedStorageConnector")
 
+KVConnectorFactory.register_connector(
+    "P2pNcclConnector",
+    "vllm.distributed.kv_transfer.kv_connector.v1.p2p.p2p_nccl_connector",
+    "P2pNcclConnector")
+
 KVConnectorFactory.register_connector(
     "LMCacheConnectorV1",
     "vllm.distributed.kv_transfer.kv_connector.v1.lmcache_connector",