[PD] Make bootstrap code common between NIXL and Mooncake (#6473)

docs/backend/pd_disaggregation.md

@@ -47,3 +47,44 @@ $ python -m sglang.launch_server --model-path deepseek-ai/DeepSeek-V3-0324 --dis
 # decode 1
 $ python -m sglang.launch_server --model-path deepseek-ai/DeepSeek-V3-0324 --disaggregation-ib-device ${device_name} --disaggregation-mode decode --host ${local_ip} --port 30001 --trust-remote-code --dist-init-addr ${decode_master_ip}:5000 --nnodes 2 --node-rank 1 --tp-size 16 --dp-size 8 --enable-dp-attention --enable-deepep-moe --deepep-mode low_latency --mem-fraction-static 0.8 --max-running-requests 128
 ```
+
+## NIXL
+### Requirements
+
+Install via pip.
+
+```bash
+pip install nixl
+```
+
+Or build from source - may be required if you already have UCX installed.
+
+```bash
+git clone https://github.com/ai-dynamo/nixl.git
+cd nixl
+pip install . --config-settings=setup-args="-Ducx_path=/path/to/ucx"
+```
+
+
+### Usage
+
+### Llama Single Node
+
+```bash
+$ python -m sglang.launch_server --model-path meta-llama/Llama-3.1-8B-Instruct --disaggregation-mode prefill --disaggregation-transfer-backend nixl
+$ python -m sglang.launch_server --model-path meta-llama/Llama-3.1-8B-Instruct --disaggregation-mode decode --port 30001 --base-gpu-id 1 --disaggregation-transfer-backend nixl
+$ python -m sglang.srt.disaggregation.mini_lb --prefill http://127.0.0.1:30000 --decode http://127.0.0.1:30001 --host 0.0.0.0 --port 8000
+```
+
+### DeepSeek Multi-Node
+
+```bash
+# prefill 0
+$ python -m sglang.launch_server --model-path deepseek-ai/DeepSeek-V3-0324 ---disaggregation-transfer-backend nixl --disaggregation-mode prefill --host ${local_ip} --port 30000 --trust-remote-code --dist-init-addr ${prefill_master_ip}:5000 --nnodes 2 --node-rank 0 --tp-size 16 --dp-size 8 --enable-dp-attention --enable-deepep-moe --deepep-mode normal --mem-fraction-static 0.8
+# prefill 1
+$ python -m sglang.launch_server --model-path deepseek-ai/DeepSeek-V3-0324 ---disaggregation-transfer-backend nixl --disaggregation-mode prefill --host ${local_ip} --port 30000 --trust-remote-code --dist-init-addr ${prefill_master_ip}:5000 --nnodes 2 --node-rank 1 --tp-size 16 --dp-size 8 --enable-dp-attention --enable-deepep-moe --deepep-mode normal --mem-fraction-static 0.8
+# decode 0
+$ python -m sglang.launch_server --model-path deepseek-ai/DeepSeek-V3-0324 ---disaggregation-transfer-backend nixl --disaggregation-mode decode --host ${local_ip} --port 30001 --trust-remote-code --dist-init-addr ${decode_master_ip}:5000 --nnodes 2 --node-rank 0 --tp-size 16 --dp-size 8 --enable-dp-attention --enable-deepep-moe --deepep-mode low_latency --mem-fraction-static 0.8 --max-running-requests 128
+# decode 1
+$ python -m sglang.launch_server --model-path deepseek-ai/DeepSeek-V3-0324 ---disaggregation-transfer-backend nixl --disaggregation-mode decode --host ${local_ip} --port 30001 --trust-remote-code --dist-init-addr ${decode_master_ip}:5000 --nnodes 2 --node-rank 1 --tp-size 16 --dp-size 8 --enable-dp-attention --enable-deepep-moe --deepep-mode low_latency --mem-fraction-static 0.8 --max-running-requests 128
+```

python/sglang/srt/disaggregation/common/__init__.py

@@ -0,0 +1 @@
+from .conn import CommonKVBootstrapServer, CommonKVManager, CommonKVReceiver

python/sglang/srt/disaggregation/common/conn.py

@@ -0,0 +1,401 @@
+from __future__ import annotations
+
+import asyncio
+import logging
+import socket
+import threading
+from functools import cache
+from typing import Dict, List, Optional, Tuple, Union
+
+import numpy as np
+import numpy.typing as npt
+import requests
+import zmq
+from aiohttp import web
+
+from sglang.srt.disaggregation.base.conn import (
+    BaseKVBootstrapServer,
+    BaseKVManager,
+    BaseKVReceiver,
+    BaseKVSender,
+    KVArgs,
+    KVPoll,
+)
+from sglang.srt.disaggregation.utils import DisaggregationMode
+from sglang.srt.server_args import ServerArgs
+from sglang.srt.utils import get_free_port, get_ip, get_local_ip_by_remote
+
+logger = logging.getLogger(__name__)
+
+
+class CommonKVManager(BaseKVManager):
+    def __init__(
+        self,
+        args: KVArgs,
+        disaggregation_mode: DisaggregationMode,
+        server_args: ServerArgs,
+        is_mla_backend: Optional[bool] = False,
+    ):
+        self.kv_args = args
+        self.is_mla_backend = is_mla_backend
+        self.disaggregation_mode = disaggregation_mode
+        # for p/d multi node infer
+        self.bootstrap_port = server_args.disaggregation_bootstrap_port
+        self.dist_init_addr = server_args.dist_init_addr
+        self.tp_size = server_args.tp_size
+        self.dp_size = server_args.dp_size
+        self.enable_dp_attention = server_args.enable_dp_attention
+        if not server_args.enable_dp_attention and server_args.dp_size != 1:
+            raise ValueError(
+                "If dp_attention is not enabled, dp size must be 1 in disaggregation mode."
+            )
+
+        self.rank_port = get_free_port()
+        if self.disaggregation_mode == DisaggregationMode.PREFILL:
+            self._register_to_bootstrap()
+        elif self.disaggregation_mode == DisaggregationMode.DECODE:
+            self.connection_pool: Dict[str, Dict[str, Union[str, int]]] = {}
+            self.prefill_tp_size_table: Dict[str, int] = {}
+            self.prefill_dp_size_table: Dict[str, int] = {}
+        else:
+            raise ValueError(
+                f"Unsupported DisaggregationMode: {self.disaggregation_mode}"
+            )
+
+    def _register_to_bootstrap(self):
+        """Register KVSender to bootstrap server via HTTP POST."""
+        if self.dist_init_addr:
+            ip_address = socket.gethostbyname(self.dist_init_addr.split(":")[0])
+        else:
+            ip_address = get_ip()
+
+        bootstrap_server_url = f"{ip_address}:{self.bootstrap_port}"
+        url = f"http://{bootstrap_server_url}/route"
+        payload = {
+            "role": "Prefill",
+            "tp_size": self.tp_size,
+            "dp_size": self.dp_size,
+            "rank_ip": get_local_ip_by_remote(),
+            "rank_port": self.rank_port,
+            "engine_rank": self.kv_args.engine_rank,
+        }
+
+        try:
+            response = requests.put(url, json=payload)
+            if response.status_code == 200:
+                logger.debug("Prefill successfully registered to bootstrap server.")
+            else:
+                logger.error(
+                    f"Prefill Failed to connect to bootstrap server: {response.status_code}, {response.text}"
+                )
+        except Exception as e:
+            logger.error(f"Prefill Failed to register to bootstrap server: {e}")
+
+    @cache
+    def _connect(self, endpoint: str):
+        socket = zmq.Context().socket(zmq.PUSH)
+        socket.connect(endpoint)
+        return socket
+
+
+class CommonKVReceiver(BaseKVReceiver):
+    _ctx = zmq.Context()
+    _socket_cache = {}
+    _socket_locks = {}
+    _global_lock = threading.Lock()
+
+    def __init__(
+        self,
+        mgr: BaseKVManager,
+        bootstrap_addr: str,
+        bootstrap_room: Optional[int] = None,
+    ):
+        self.bootstrap_room = bootstrap_room
+        self.bootstrap_addr = bootstrap_addr
+        self.kv_mgr = mgr
+
+        if self.bootstrap_addr not in self.kv_mgr.prefill_dp_size_table:
+            self.prefill_tp_size, self.prefill_dp_size = (
+                self._get_prefill_dp_size_from_server()
+            )
+            if self.prefill_tp_size is None or self.prefill_dp_size is None:
+                logger.error(
+                    f"Could not fetch prefill parallel info for bootstrap_addr: {self.bootstrap_addr}"
+                )
+            else:
+                self.kv_mgr.prefill_tp_size_table[self.bootstrap_addr] = (
+                    self.prefill_tp_size
+                )
+                self.kv_mgr.prefill_dp_size_table[self.bootstrap_addr] = (
+                    self.prefill_dp_size
+                )
+        else:
+            self.prefill_tp_size = self.kv_mgr.prefill_tp_size_table[
+                self.bootstrap_addr
+            ]
+            self.prefill_dp_size = self.kv_mgr.prefill_dp_size_table[
+                self.bootstrap_addr
+            ]
+
+        # Currently, we don't allow prefill instance and decode instance to
+        # have different TP sizes per DP rank, except for models using MLA.
+        local_tp_size_per_dp_rank = self.kv_mgr.tp_size // self.kv_mgr.dp_size
+        prefill_tp_size_per_dp_rank = self.prefill_tp_size // self.prefill_dp_size
+        if local_tp_size_per_dp_rank == prefill_tp_size_per_dp_rank:
+            self.target_tp_rank = (
+                self.kv_mgr.kv_args.engine_rank % local_tp_size_per_dp_rank
+            )
+            self.required_dst_info_num = 1
+            self.target_tp_ranks = [self.target_tp_rank]
+        elif local_tp_size_per_dp_rank > prefill_tp_size_per_dp_rank:
+            assert (
+                self.kv_mgr.is_mla_backend
+            ), "PD with different TP sizes per DP rank is not yet supported for non-MLA models"
+            self.target_tp_rank = (
+                self.kv_mgr.kv_args.engine_rank % local_tp_size_per_dp_rank
+            ) // (local_tp_size_per_dp_rank // prefill_tp_size_per_dp_rank)
+            self.required_dst_info_num = (
+                local_tp_size_per_dp_rank // prefill_tp_size_per_dp_rank
+            )
+            self.target_tp_ranks = [self.target_tp_rank]
+        else:
+            assert (
+                self.kv_mgr.is_mla_backend
+            ), "PD with different TP sizes per DP rank is not yet supported for non-MLA models"
+
+            # For non-MLA models, one decode rank needs to retrieve KVCache from multiple prefill ranks for non MLA models;
+            self.target_tp_ranks = [
+                rank
+                for rank in range(
+                    (self.kv_mgr.kv_args.engine_rank % local_tp_size_per_dp_rank)
+                    * (prefill_tp_size_per_dp_rank // local_tp_size_per_dp_rank),
+                    (self.kv_mgr.kv_args.engine_rank % local_tp_size_per_dp_rank + 1)
+                    * (prefill_tp_size_per_dp_rank // local_tp_size_per_dp_rank),
+                )
+            ]
+
+            # For MLA models, we can retrieve KVCache from only one prefill rank, but we still need to maintain
+            # multiple connections in the connection pool and have to send dummy requests to other prefill ranks,
+            # or the KVPoll will never be set correctly
+            self.target_tp_rank = self.target_tp_ranks[0]
+            self.required_dst_info_num = 1
+
+        self.target_dp_group = bootstrap_room % self.prefill_dp_size
+
+        # NOTE: key distinguished by bootstrap_addr, target_dp_group, and target_tp_rank
+        bootstrap_key = (
+            f"{self.bootstrap_addr}_{self.target_dp_group}_{self.target_tp_rank}"
+        )
+
+        if bootstrap_key not in self.kv_mgr.connection_pool:
+            bootstrap_infos = []
+            for target_tp_rank in self.target_tp_ranks:
+                bootstrap_info = self._get_bootstrap_info_from_server(
+                    target_tp_rank,
+                    self.target_dp_group,
+                )
+                if bootstrap_info is not None:
+                    # NOTE: only support MLA for now: select one prefill rank as real rank
+                    bootstrap_info["is_dummy"] = not bool(
+                        target_tp_rank == self.target_tp_rank
+                        or self.target_tp_rank is None
+                    )
+                    bootstrap_infos.append(bootstrap_info)
+                else:
+                    logger.error(
+                        f"Could not fetch bootstrap info for engine rank: {self.kv_mgr.kv_args.engine_rank} and target_dp_group: {self.target_dp_group}"
+                    )
+            self.bootstrap_infos = bootstrap_infos
+
+            if len(self.bootstrap_infos) == 0:
+                logger.error(
+                    f"Could not fetch bootstrap info for engine rank: {self.kv_mgr.kv_args.engine_rank}"
+                )
+            else:
+                self.kv_mgr.connection_pool[bootstrap_key] = self.bootstrap_infos
+                # Register kv_args only once to prefill KVManager according to the info fetched from the bootstrap server
+                self._register_kv_args()
+        else:
+            self.bootstrap_infos = self.kv_mgr.connection_pool[bootstrap_key]
+
+        assert len(self.bootstrap_infos) > 0
+
+    def _get_bootstrap_info_from_server(self, engine_rank, target_dp_group):
+        """Fetch the bootstrap info from the bootstrap server."""
+        try:
+            url = f"http://{self.bootstrap_addr}/route?engine_rank={engine_rank}&target_dp_group={target_dp_group}"
+            response = requests.get(url)
+            if response.status_code == 200:
+                bootstrap_info = response.json()
+                return bootstrap_info
+            else:
+                logger.error(
+                    f"Failed to get prefill server info: {response.status_code}, {response.text}"
+                )
+                return None
+        except Exception as e:
+            logger.error(f"Error fetching prefill info from bootstrap: {e}")
+            return None
+
+    def _get_prefill_dp_size_from_server(self) -> int:
+        """Fetch the prefill parallel info from the bootstrap server."""
+        try:
+            url = f"http://{self.bootstrap_addr}/route?engine_rank={-1}&target_dp_group={-1}"
+            response = requests.get(url)
+            if response.status_code == 200:
+                prefill_parallel_info = response.json()
+                return int(prefill_parallel_info["prefill_tp_size"]), int(
+                    prefill_parallel_info["prefill_dp_size"]
+                )
+            else:
+                logger.error(
+                    f"Failed to get prefill parallel info: {response.status_code}, {response.text}"
+                )
+                return None
+        except Exception as e:
+            logger.error(f"Error fetching prefill parallel info from bootstrap: {e}")
+            return None
+
+    @classmethod
+    def _connect(cls, endpoint: str):
+        with cls._global_lock:
+            if endpoint not in cls._socket_cache:
+                sock = cls._ctx.socket(zmq.PUSH)
+                sock.connect(endpoint)
+                cls._socket_cache[endpoint] = sock
+                cls._socket_locks[endpoint] = threading.Lock()
+            return cls._socket_cache[endpoint], cls._socket_locks[endpoint]
+
+    def _register_kv_args(self):
+        pass
+
+    def failure_exception(self):
+        raise Exception("Fake KVReceiver Exception")
+
+
+class CommonKVBootstrapServer(BaseKVBootstrapServer):
+    def __init__(self, port: int):
+        self.port = port
+        self.app = web.Application()
+        self.store = dict()
+        self.lock = asyncio.Lock()
+        self._setup_routes()
+        self.tp_size = None
+        self.dp_size = None
+        self.tp_size_per_dp_rank = None
+        self.prefill_port_table: Dict[int, Dict[int, Dict[str, Union[str, int]]]] = {}
+
+        # Start bootstrap server
+        self.thread = threading.Thread(target=self._run_server, daemon=True)
+        self.run()
+
+    def run(self):
+        self.thread.start()
+
+    def _setup_routes(self):
+        self.app.router.add_route("*", "/route", self._handle_route)
+
+    async def _handle_route(self, request: web.Request):
+        method = request.method
+        if method == "PUT":
+            return await self._handle_route_put(request)
+        elif method == "GET":
+            return await self._handle_route_get(request)
+        else:
+            return web.Response(
+                text="Method not allowed", status=405, content_type="application/json"
+            )
+
+    async def _handle_route_put(self, request: web.Request):
+        data = await request.json()
+        role = data["role"]
+        tp_size = data["tp_size"]
+        dp_size = data["dp_size"]
+        rank_ip = data["rank_ip"]
+        rank_port = int(data["rank_port"])
+        engine_rank = int(data["engine_rank"])
+
+        if self.tp_size is None:
+            self.tp_size = tp_size
+
+        if self.dp_size is None:
+            self.dp_size = dp_size
+
+        tp_size_per_dp_rank = tp_size // dp_size
+        if self.tp_size_per_dp_rank == None:
+            self.tp_size_per_dp_rank = tp_size_per_dp_rank
+
+        # Add lock to make sure thread-safe
+        if role == "Prefill":
+            dp_group = engine_rank // tp_size_per_dp_rank
+            tp_rank_in_dp_group = engine_rank % tp_size_per_dp_rank
+
+            async with self.lock:
+                if dp_group not in self.prefill_port_table:
+                    self.prefill_port_table[dp_group] = {}
+
+            self.prefill_port_table[dp_group][tp_rank_in_dp_group] = {
+                "rank_ip": rank_ip,
+                "rank_port": rank_port,
+            }
+            logger.debug(
+                f"Register Prefill bootstrap: {engine_rank} with rank_ip: {rank_ip} and rank_port: {rank_port}"
+            )
+
+        return web.Response(text="OK", status=200)
+
+    async def _handle_route_get(self, request: web.Request):
+        engine_rank = request.query.get("engine_rank")
+        target_dp_group = request.query.get("target_dp_group")
+        if not engine_rank or not target_dp_group:
+            return web.Response(text="Missing inputs for bootstrap server.", status=400)
+
+        # Currently we use engine_rank == -1 and target_dp_group == -1 to sync dp size
+        if int(engine_rank) == -1 and int(target_dp_group) == -1:
+            prefill_parallel_info = {
+                "prefill_tp_size": self.tp_size,
+                "prefill_dp_size": self.dp_size,
+            }
+            return web.json_response(prefill_parallel_info, status=200)
+
+        # Find corresponding prefill info
+        async with self.lock:
+            bootstrap_info = self.prefill_port_table[int(target_dp_group)][
+                int(engine_rank)
+            ]
+
+        if bootstrap_info is not None:
+            return web.json_response(bootstrap_info, status=200)
+        else:
+            return web.Response(text="Bootstrap info not Found", status=404)
+
+    def _run_server(self):
+        try:
+            # Event Loop
+            self._loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(self._loop)
+
+            self._runner = web.AppRunner(self.app)
+            self._loop.run_until_complete(self._runner.setup())
+
+            site = web.TCPSite(self._runner, port=self.port)
+            self._loop.run_until_complete(site.start())
+            self._loop.run_forever()
+        except Exception as e:
+            logger.error(f"Server error: {str(e)}")
+        finally:
+            # Cleanup
+            self._loop.run_until_complete(self._runner.cleanup())
+            self._loop.close()
+
+    def close(self):
+        """Shutdown"""
+        if self._loop is not None and self._loop.is_running():
+            self._loop.call_soon_threadsafe(self._loop.stop)
+            logger.info("Stopping server loop...")
+
+        if self.thread.is_alive():
+            self.thread.join(timeout=2)
+            logger.info("Server thread stopped")
+
+    def poll(self) -> KVPoll: ...

python/sglang/srt/disaggregation/mooncake/conn.py

@@ -29,7 +29,10 @@ from sglang.srt.disaggregation.base.conn import (
     KVPoll,
 )
 from sglang.srt.disaggregation.mooncake.transfer_engine import MooncakeTransferEngine
-from sglang.srt.disaggregation.utils import DisaggregationMode
+from sglang.srt.disaggregation.utils import (
+    DisaggregationMode,
+    group_concurrent_contiguous,
+)
 from sglang.srt.server_args import ServerArgs
 from sglang.srt.utils import (
     get_free_port,
@@ -41,23 +44,6 @@ from sglang.srt.utils import (
 logger = logging.getLogger(__name__)
 
 
-def group_concurrent_contiguous(
-    src_indices: npt.NDArray[np.int64], dst_indices: npt.NDArray[np.int64]
-) -> Tuple[List[npt.NDArray[np.int64]], List[npt.NDArray[np.int64]]]:
-    """Vectorised NumPy implementation."""
-    if src_indices.size == 0:
-        return [], []
-
-    brk = np.where((np.diff(src_indices) != 1) | (np.diff(dst_indices) != 1))[0] + 1
-    src_groups = np.split(src_indices, brk)
-    dst_groups = np.split(dst_indices, brk)
-
-    src_groups = [g.tolist() for g in src_groups]
-    dst_groups = [g.tolist() for g in dst_groups]
-
-    return src_groups, dst_groups
-
-
 class KVTransferError(Exception):
     def __init__(self, bootstrap_room: int, failure_reason: str):
         super().__init__(failure_reason)

python/sglang/srt/disaggregation/nixl/conn.py

@@ -18,40 +18,23 @@ import requests
 import zmq
 from aiohttp import web
 
-from sglang.srt.disaggregation.base.conn import (
+from sglang.srt.disaggregation.base.conn import BaseKVSender, KVArgs, KVPoll
-    BaseKVBootstrapServer,
+from sglang.srt.disaggregation.common.conn import (
-    BaseKVManager,
+    CommonKVBootstrapServer,
-    BaseKVReceiver,
+    CommonKVManager,
-    BaseKVSender,
+    CommonKVReceiver,
-    KVArgs,
+)
-    KVPoll,
+from sglang.srt.disaggregation.utils import (
+    DisaggregationMode,
+    group_concurrent_contiguous,
 )
-from sglang.srt.disaggregation.utils import DisaggregationMode
 from sglang.srt.server_args import ServerArgs
-from sglang.srt.utils import get_free_port, get_ip, get_local_ip_by_remote
+from sglang.srt.utils import get_local_ip_by_remote
 
 logger = logging.getLogger(__name__)
 
 NixlEngineInfo: TypeAlias = Dict[str, Union[str, int]]
 
-
-def group_concurrent_contiguous(
-    src_indices: npt.NDArray[np.int64], dst_indices: npt.NDArray[np.int64]
-) -> Tuple[List[npt.NDArray[np.int64]], List[npt.NDArray[np.int64]]]:
-    """Vectorised NumPy implementation."""
-    if src_indices.size == 0:
-        return [], []
-
-    brk = np.where((np.diff(src_indices) != 1) | (np.diff(dst_indices) != 1))[0] + 1
-    src_groups = np.split(src_indices, brk)
-    dst_groups = np.split(dst_indices, brk)
-
-    src_groups = [g.tolist() for g in src_groups]
-    dst_groups = [g.tolist() for g in dst_groups]
-
-    return src_groups, dst_groups
-
-
 GUARD = "NixlMsgGuard".encode("ascii")
 
 
@@ -61,11 +44,13 @@ class TransferInfo:
     endpoint: str
     dst_port: int
     agent_metadata: bytes
+    agent_name: str
     dst_kv_ptrs: list[int]
     dst_kv_indices: npt.NDArray[np.int64]
     dst_aux_ptrs: list[int]
     dst_aux_index: int
     dst_gpu_id: int
+    required_dst_info_num: int
 
     def is_dummy(self):
         return self.endpoint == ""
@@ -79,11 +64,13 @@ class TransferInfo:
                 endpoint="",
                 dst_port=0,
                 agent_metadata=b"",
+                agent_name="",
                 dst_kv_ptrs=[],
                 dst_kv_indices=np.array([], dtype=np.int64),
                 dst_aux_ptrs=[],
                 dst_aux_index=0,
                 dst_gpu_id=0,
+                required_dst_info_num=0,
             )
         else:
             return cls(
@@ -91,11 +78,13 @@ class TransferInfo:
                 endpoint=msg[1].decode("ascii"),
                 dst_port=int(msg[2].decode("ascii")),
                 agent_metadata=msg[3],
-                dst_kv_ptrs=list(struct.unpack(f"{len(msg[4])//8}Q", msg[4])),
+                agent_name=msg[4].decode("ascii"),
-                dst_kv_indices=np.frombuffer(msg[5], dtype=np.int64),
+                dst_kv_ptrs=list(struct.unpack(f"{len(msg[5])//8}Q", msg[5])),
-                dst_aux_ptrs=list(struct.unpack(f"{len(msg[6])//8}Q", msg[6])),
+                dst_kv_indices=np.frombuffer(msg[6], dtype=np.int64),
-                dst_aux_index=int(msg[7].decode("ascii")),
+                dst_aux_ptrs=list(struct.unpack(f"{len(msg[7])//8}Q", msg[7])),
-                dst_gpu_id=int(msg[8].decode("ascii")),
+                dst_aux_index=int(msg[8].decode("ascii")),
+                dst_gpu_id=int(msg[9].decode("ascii")),
+                required_dst_info_num=int(msg[10].decode("ascii")),
             )
 
 
@@ -116,7 +105,7 @@ class TransferStatus:
         return self.num_kvs_expected == len(self.received_kvs) and self.received_aux
 
 
-class NixlKVManager(BaseKVManager):
+class NixlKVManager(CommonKVManager):
     def __init__(
         self,
         args: KVArgs,
@@ -124,6 +113,7 @@ class NixlKVManager(BaseKVManager):
         server_args: ServerArgs,
         is_mla_backend: Optional[bool] = False,
     ):
+        super().__init__(args, disaggregation_mode, server_args, is_mla_backend)
         try:
             from nixl._api import nixl_agent
         except ImportError as e:
@@ -133,38 +123,15 @@ class NixlKVManager(BaseKVManager):
                 "to run SGLang with NixlTransferEngine."
             ) from e
         self.agent = nixl_agent(str(uuid.uuid4()))
-        self.kv_args = args
-        self.disaggregation_mode = disaggregation_mode
-        # for p/d multi node infer
-        self.bootstrap_port = server_args.disaggregation_bootstrap_port
-        self.dist_init_addr = server_args.dist_init_addr
-        self.tp_size = server_args.tp_size
-
-        self.tp_rank = args.engine_rank
-        self.enable_dp_attention = server_args.enable_dp_attention
-        if self.enable_dp_attention:
-            assert (
-                server_args.dp_size > 1
-            ), "If dp_attention is enabled, dp size must be greater than 1 in disaggregation mode."
-            self.dp_size = server_args.dp_size
-            self.tp_size_of_dp = server_args.tp_size // server_args.dp_size
-            self.attn_tp_rank = args.engine_rank % self.tp_size_of_dp
-            self.dp_rank = args.engine_rank // self.tp_size_of_dp
-
-        self.rank_port = None
         self.server_socket = zmq.Context().socket(zmq.PULL)
         self.register_buffer_to_engine()
 
-        self.rank_port = get_free_port()
         if self.disaggregation_mode == DisaggregationMode.PREFILL:
+            self.request_status = {}
             self.transfer_infos: Dict[int, TransferInfo] = {}
-            self.condition = threading.Condition()
+            self.peer_names: Dict[str, str] = {}
-            self.peer_names: Dict[int, str] = {}
             self._start_bootstrap_thread()
-            self._register_to_bootstrap()
         elif self.disaggregation_mode == DisaggregationMode.DECODE:
-            # bootstrap key -> (remote_engine_rank -> possible remote source info)
-            self.prefill_peer_infos: Dict[str, list[Dict[int, NixlEngineInfo]]] = {}
             self.transfer_statuses: Dict[int, TransferStatus] = defaultdict(
                 TransferStatus
             )
@@ -173,6 +140,18 @@ class NixlKVManager(BaseKVManager):
                 f"Unsupported DisaggregationMode: {self.disaggregation_mode}"
             )
 
+    def check_status(self, bootstrap_room: int):
+        return self.request_status[bootstrap_room]
+
+    def update_status(self, bootstrap_room: int, status: KVPoll):
+        if bootstrap_room not in self.request_status:
+            self.request_status[bootstrap_room] = status
+        else:
+            # NOTE: The prefill engine could recv bootstrapping first
+            self.request_status[bootstrap_room] = max(
+                self.request_status[bootstrap_room], status
+            )
+
     def register_buffer_to_engine(self):
         kv_addrs = []
         for kv_data_ptr, kv_data_len in zip(
@@ -193,16 +172,10 @@ class NixlKVManager(BaseKVManager):
         if not self.aux_descs:
             raise Exception("NIXL memory registration failed for aux tensors")
 
-    @cache
+    def _add_remote(self, agent_name: str, agent_metadata: bytes):
-    def _connect(self, endpoint: str):
+        if agent_name not in self.peer_names:
-        socket = zmq.Context().socket(zmq.PUSH)
+            self.peer_names[agent_name] = self.agent.add_remote_agent(agent_metadata)
-        socket.connect(endpoint)
+        return self.peer_names[agent_name]
-        return socket
-
-    def _add_remote(self, room: int, agent_metadata: bytes):
-        if room not in self.peer_names:
-            self.peer_names[room] = self.agent.add_remote_agent(agent_metadata)
-        return self.peer_names[room]
 
     def send_kvcache(
         self,
@@ -300,40 +273,38 @@ class NixlKVManager(BaseKVManager):
         assert self.disaggregation_mode == DisaggregationMode.PREFILL
         assert not is_last or (is_last and aux_index is not None)
 
-        # Wait for transfer info to be populated by bootstrap thread.
+        reqs_to_be_processed = self.transfer_infos[bootstrap_room].values()
-        with self.condition:
+        handles = []
-            self.condition.wait_for(lambda: bootstrap_room in self.transfer_infos)
+        for req in reqs_to_be_processed:
-            req = self.transfer_infos[bootstrap_room]
+            assert bootstrap_room == req.room
-        assert bootstrap_room == req.room
+            if req.is_dummy():
+                return []
 
-        if req.is_dummy():
+            peer_name = self._add_remote(req.agent_name, req.agent_metadata)
-            return []
+            chunked_dst_kv_indice = req.dst_kv_indices[index_slice]
+            assert len(chunked_dst_kv_indice) == len(kv_indices)
 
-        peer_name = self._add_remote(bootstrap_room, req.agent_metadata)
+            notif = "_".join([str(req.room), "kv", str(chunk_id), str(int(is_last))])
-        chunked_dst_kv_indice = req.dst_kv_indices[index_slice]
+            kv_xfer_handle = self.send_kvcache(
-        assert len(chunked_dst_kv_indice) == len(kv_indices)
-
-        notif = "_".join([str(req.room), "kv", str(chunk_id), str(int(is_last))])
-        kv_xfer_handle = self.send_kvcache(
-            peer_name,
-            kv_indices,
-            req.dst_kv_ptrs,
-            chunked_dst_kv_indice,
-            req.dst_gpu_id,
-            notif,
-        )
-        handles = [kv_xfer_handle]
-        # Only the last chunk we need to send the aux data.
-        if is_last:
-            assert aux_index is not None
-            aux_xfer_handle = self.send_aux(
                 peer_name,
-                aux_index,
+                kv_indices,
-                req.dst_aux_ptrs,
+                req.dst_kv_ptrs,
-                req.dst_aux_index,
+                chunked_dst_kv_indice,
-                str(req.room) + "_aux",
+                req.dst_gpu_id,
+                notif,
             )
-            handles.append(aux_xfer_handle)
+            handles.append(kv_xfer_handle)
+            # Only the last chunk we need to send the aux data.
+            if is_last:
+                assert aux_index is not None
+                aux_xfer_handle = self.send_aux(
+                    peer_name,
+                    aux_index,
+                    req.dst_aux_ptrs,
+                    req.dst_aux_index,
+                    str(req.room) + "_aux",
+                )
+                handles.append(aux_xfer_handle)
         return handles
 
     def update_transfer_status(self):
@@ -348,7 +319,7 @@ class NixlKVManager(BaseKVManager):
                 room = int(components[0])
                 if components[1] == "kv":
                     chunk_id = int(components[2])
-                    is_last = bool(components[3])
+                    is_last = bool(int(components[3]))
                     self.transfer_statuses[room].received_kvs.add(chunk_id)
                     if is_last:
                         self.transfer_statuses[room].num_kvs_expected = chunk_id + 1
@@ -360,34 +331,6 @@ class NixlKVManager(BaseKVManager):
             return False
         return self.transfer_statuses[room].is_done()
 
-    def _register_to_bootstrap(self):
-        """Register KVSender to bootstrap server via HTTP POST."""
-        if self.dist_init_addr:
-            ip_address = socket.gethostbyname(self.dist_init_addr.split(":")[0])
-        else:
-            ip_address = get_ip()
-
-        bootstrap_server_url = f"{ip_address}:{self.bootstrap_port}"
-        url = f"http://{bootstrap_server_url}/route"
-        payload = {
-            "role": "Prefill",
-            "rank_ip": get_local_ip_by_remote(),
-            "rank_port": self.rank_port,
-            "engine_rank": self.kv_args.engine_rank,
-            "agent_name": self.agent.name,
-        }
-
-        try:
-            response = requests.put(url, json=payload)
-            if response.status_code == 200:
-                logger.debug("Prefill successfully registered to bootstrap server.")
-            else:
-                logger.error(
-                    f"Prefill Failed to connect to bootstrap server: {response.status_code}, {response.text}"
-                )
-        except Exception as e:
-            logger.error(f"Prefill Failed to register to bootstrap server: {e}")
-
     def _start_bootstrap_thread(self):
         self.server_socket.bind(f"tcp://{get_local_ip_by_remote()}:{self.rank_port}")
 
@@ -405,10 +348,19 @@ class NixlKVManager(BaseKVManager):
                 room = waiting_req_bytes[0].decode("ascii")
                 if room == "None":
                     continue
+                required_dst_info_num = int(waiting_req_bytes[10].decode("ascii"))
                 room = int(room)
-                with self.condition:
+                agent_name = waiting_req_bytes[4].decode("ascii")
-                    self.transfer_infos[room] = TransferInfo.from_zmq(waiting_req_bytes)
+                if room not in self.transfer_infos:
-                    self.condition.notify_all()
+                    self.transfer_infos[room] = {}
+                self.transfer_infos[room][agent_name] = TransferInfo.from_zmq(
+                    waiting_req_bytes
+                )
+
+                logger.debug(f"got info {room=} {agent_name=} {required_dst_info_num=}")
+                if len(self.transfer_infos[room]) == required_dst_info_num:
+                    logger.debug(f"{room=} is bootstrapped")
+                    self.update_status(room, KVPoll.WaitingForInput)
 
         threading.Thread(target=bootstrap_thread).start()
 
@@ -423,6 +375,9 @@ class NixlKVSender(BaseKVSender):
         self.xfer_handles = []
         self.has_sent = False
         self.chunk_id = 0
+        self.kv_mgr.update_status(self.bootstrap_room, KVPoll.Bootstrapping)
+        # inner state
+        self.curr_idx = 0
 
     def init(self, num_kv_indices: int, aux_index: Optional[int] = None):
         self.num_kv_indices = num_kv_indices
@@ -431,9 +386,11 @@ class NixlKVSender(BaseKVSender):
     def send(
         self,
         kv_indices: npt.NDArray[np.int64],
-        index_slice: slice,
-        is_last: bool,
     ):
+        index_slice = slice(self.curr_idx, self.curr_idx + len(kv_indices))
+        self.curr_idx += len(kv_indices)
+        is_last = self.curr_idx == self.num_kv_indices
+
         new_xfer_handles = self.kv_mgr.add_transfer_request(
             self.bootstrap_room,
             kv_indices,
@@ -449,7 +406,7 @@ class NixlKVSender(BaseKVSender):
 
     def poll(self) -> KVPoll:
         if not self.has_sent:
-            return KVPoll.WaitingForInput  # type: ignore
+            return self.kv_mgr.check_status(self.bootstrap_room)
         states = [self.kv_mgr.agent.check_xfer_state(x) for x in self.xfer_handles]
         if all([x == "DONE" for x in states]):
             return KVPoll.Success  # type: ignore
@@ -461,128 +418,40 @@ class NixlKVSender(BaseKVSender):
         raise Exception("Fake KVSender Exception")
 
 
-class NixlKVReceiver(BaseKVReceiver):
+class NixlKVReceiver(CommonKVReceiver):
-
     def __init__(
         self,
         mgr: NixlKVManager,
         bootstrap_addr: str,
         bootstrap_room: Optional[int] = None,
     ):
-        self.bootstrap_room = bootstrap_room
-        self.bootstrap_addr = bootstrap_addr
-        self.kv_mgr = mgr
         self.started_transfer = False
-
+        super().__init__(mgr, bootstrap_addr, bootstrap_room)
-        # NOTE: key distinguished by bootstrap_addr and engine_rank
-        bootstrap_key = f"{self.bootstrap_addr}_{self.kv_mgr.kv_args.engine_rank}"
-
-        if bootstrap_key not in self.kv_mgr.prefill_peer_infos:
-            self.bootstrap_info = self._get_bootstrap_info_from_server(
-                self.kv_mgr.kv_args.engine_rank
-            )
-            if self.bootstrap_info is None:
-                logger.error(
-                    f"Could not fetch bootstrap info for engine rank: {self.kv_mgr.kv_args.engine_rank}"
-                )
-            else:
-                self.kv_mgr.prefill_peer_infos[bootstrap_key] = self.bootstrap_info
-        else:
-            self.bootstrap_info = self.kv_mgr.prefill_peer_infos[bootstrap_key]
-        assert self.bootstrap_info is not None
-
-    # return a list of remotes in a dict, [(remote_engine_rank -> NixlEngineInfo), ...]
-    # In each dict, there are multiple possible remotes named "equal sources".
-    # We only need to select one to split the traffic. i.e. we totally select len(list) remotes.
-    def _get_bootstrap_info_from_server(
-        self, engine_rank
-    ) -> Optional[List[Dict[int, NixlEngineInfo]]]:
-        """Fetch the bootstrap info from the bootstrap server."""
-        try:
-            if self.kv_mgr.enable_dp_attention:
-                url = f"http://{self.bootstrap_addr}/route"
-                response = requests.get(url)
-                if response.status_code != 200:
-                    logger.error(
-                        f"Failed to get prefill server info: {response.status_code}, {response.text}"
-                    )
-                    return None
-
-                bootstrap_info = response.json()
-                assert isinstance(bootstrap_info, dict)
-                bootstrap_info = {int(k): v for k, v in bootstrap_info.items()}
-
-                # split out who need to send to this rank.
-                # currently for dpsk mla model, those ranks share the same latent cache.
-                # pick one as the real source
-
-                prefill_tp_size = len(bootstrap_info.keys())
-
-                assert (
-                    prefill_tp_size >= self.kv_mgr.tp_size_of_dp
-                ), f"Only support Prefill TP size >= Decode TP size of DP, now we have {prefill_tp_size} vs {self.kv_mgr.tp_size_of_dp}"
-
-                num_remote_tp_rank_we_managed = (
-                    prefill_tp_size // self.kv_mgr.tp_size_of_dp
-                )
-
-                # We handle [num * self.attn_tp_rank, num * self.attn_tp_rank + num)
-                remote_tp_ranks = list(range(0, prefill_tp_size))
-                # split it into tp_size_of_dp parts and get our part
-                remote_tp_ranks_grouped = [
-                    remote_tp_ranks[i : i + num_remote_tp_rank_we_managed]
-                    for i in range(0, prefill_tp_size, self.kv_mgr.tp_size_of_dp)
-                ]
-                managed_ranks = remote_tp_ranks_grouped[self.kv_mgr.attn_tp_rank]
-
-                assert len(managed_ranks) == num_remote_tp_rank_we_managed
-
-                logger.debug(
-                    f"Rank {self.kv_mgr.kv_args.engine_rank} source can be {managed_ranks}"
-                )
-
-                return [
-                    {
-                        rk: bootstrap_info[rk]
-                        for rk in bootstrap_info.keys()
-                        if rk in managed_ranks
-                    }
-                ]
-            else:
-                url = f"http://{self.bootstrap_addr}/route?engine_rank={engine_rank}"
-                response = requests.get(url)
-                if response.status_code == 200:
-                    bootstrap_info = response.json()
-                    return [{engine_rank: bootstrap_info}]
-                else:
-                    logger.error(
-                        f"Failed to get prefill server info: {response.status_code}, {response.text}"
-                    )
-                    return None
-        except Exception as e:
-            logger.error(f"Error fetching prefill info from bootstrap: {e}")
-            return None
-
-    @cache
-    def _connect(self, endpoint: str):
-        socket = zmq.Context().socket(zmq.PUSH)
-        socket.connect(endpoint)
-        return socket
 
     def init(self, kv_indices: npt.NDArray[np.int64], aux_index: Optional[int] = None):
-
+        for bootstrap_info in self.bootstrap_infos:
-        assert self.bootstrap_info is not None
+            self.prefill_server_url = (
-        assert self.bootstrap_room is not None
+                f"{bootstrap_info['rank_ip']}:{bootstrap_info['rank_port']}"
-
-        for equal_sources in self.bootstrap_info:
-            remote_rank = list(equal_sources.keys())[
-                self.bootstrap_room % len(equal_sources)
-            ]
-            self.prefill_server_url = f"{equal_sources[remote_rank]['rank_ip']}:{equal_sources[remote_rank]['rank_port']}"
-            logger.debug(
-                f"Fetched bootstrap info for engine rank: {self.kv_mgr.kv_args.engine_rank}, source: {remote_rank}, all: {list(equal_sources.keys())}"
             )
+            logger.debug(
+                f"Fetched bootstrap info: {bootstrap_info} for engine rank: {self.kv_mgr.kv_args.engine_rank}"
+            )
+            is_dummy = bootstrap_info["is_dummy"]
 
+            # TODO: just send "" for indices for dummy
+            if is_dummy:
+                # TODO: need to set success??
+                sock, lock = self._connect("tcp://" + self.prefill_server_url)
+                with lock:
+                    sock.send_multipart(
+                        [
+                            GUARD,
+                            str(self.bootstrap_room).encode("ascii"),
+                        ]
+                    )
+                continue
+
+            # TODO: send_kv_args earlier
             packed_kv_data_ptrs = b"".join(
                 struct.pack("Q", ptr) for ptr in self.kv_mgr.kv_args.kv_data_ptrs
             )
@@ -593,30 +462,22 @@ class NixlKVReceiver(BaseKVReceiver):
             logger.debug(
                 f"Sending to {self.prefill_server_url} with bootstrap room {self.bootstrap_room}"
             )
-            self._connect("tcp://" + self.prefill_server_url).send_multipart(
+            sock, lock = self._connect("tcp://" + self.prefill_server_url)
-                [
+            with lock:
-                    GUARD,
+                sock.send_multipart(
-                    str(self.bootstrap_room).encode("ascii"),
-                    get_local_ip_by_remote().encode("ascii"),
-                    str(self.kv_mgr.rank_port).encode("ascii"),
-                    self.kv_mgr.agent.get_agent_metadata(),
-                    packed_kv_data_ptrs,
-                    kv_indices.tobytes(),
-                    packed_aux_data_ptrs,
-                    str(aux_index).encode("ascii"),
-                    str(self.kv_mgr.kv_args.gpu_id).encode("ascii"),
-                ]
-            )
-
-            for dummy_rank in equal_sources.keys():
-                if dummy_rank == remote_rank:
-                    continue
-                dummy_info = equal_sources[dummy_rank]
-                dummy_url = f"{dummy_info['rank_ip']}:{dummy_info['rank_port']}"
-                self._connect("tcp://" + dummy_url).send_multipart(
                     [
                         GUARD,
                         str(self.bootstrap_room).encode("ascii"),
+                        get_local_ip_by_remote().encode("ascii"),
+                        str(self.kv_mgr.rank_port).encode("ascii"),
+                        self.kv_mgr.agent.get_agent_metadata(),
+                        self.kv_mgr.agent.name.encode("ascii"),
+                        packed_kv_data_ptrs,
+                        kv_indices.tobytes(),
+                        packed_aux_data_ptrs,
+                        str(aux_index).encode("ascii"),
+                        str(self.kv_mgr.kv_args.gpu_id).encode("ascii"),
+                        str(self.required_dst_info_num).encode("ascii"),
                     ]
                 )
 
@@ -632,152 +493,12 @@ class NixlKVReceiver(BaseKVReceiver):
             return KVPoll.Success  # type: ignore
         return KVPoll.WaitingForInput  # type: ignore
 
+    def _register_kv_args(self):
+        pass
+
     def failure_exception(self):
         raise Exception("Fake KVReceiver Exception")
 
 
-class NixlKVBootstrapServer(BaseKVBootstrapServer):
+class NixlKVBootstrapServer(CommonKVBootstrapServer):
-    def __init__(self, port: int):
+    pass
-        logger.debug(f"NixlKVBootstrapServer started on port {port}")
-        self.port = port
-        self.app = web.Application()
-        self.store = dict()
-        self.lock = asyncio.Lock()
-        self._setup_routes()
-        self.prefill_port_table: Dict[int, Dict[str, Union[str, int]]] = {}
-
-        # Start bootstrap server
-        self.thread = threading.Thread(target=self._run_server, daemon=True)
-        self.run()
-
-    def run(self):
-        self.thread.start()
-
-    def _setup_routes(self):
-        self.app.router.add_route("*", "/metadata", self._handle_metadata)
-        self.app.router.add_route("*", "/route", self._handle_route)
-
-    async def _handle_metadata(self, request: web.Request):
-        key = request.query.get("key", "")
-
-        if request.method == "GET":
-            return await self._handle_metadata_get(key)
-        elif request.method == "PUT":
-            return await self._handle_metadata_put(key, request)
-        elif request.method == "DELETE":
-            return await self._handle_metadata_delete(key)
-        return web.Response(
-            text="Method not allowed", status=405, content_type="application/json"
-        )
-
-    async def _handle_metadata_get(self, key):
-        async with self.lock:
-            value = self.store.get(key)
-        if value is None:
-            return web.Response(
-                text="metadata not found", status=404, content_type="application/json"
-            )
-        return web.Response(body=value, status=200, content_type="application/json")
-
-    async def _handle_metadata_put(self, key, request):
-        data = await request.read()
-        async with self.lock:
-            self.store[key] = data
-        return web.Response(
-            text="metadata updated", status=200, content_type="application/json"
-        )
-
-    async def _handle_metadata_delete(self, key):
-        async with self.lock:
-            if key not in self.store:
-                return web.Response(
-                    text="metadata not found",
-                    status=404,
-                    content_type="application/json",
-                )
-            del self.store[key]
-        return web.Response(
-            text="metadata deleted", status=200, content_type="application/json"
-        )
-
-    async def _handle_route(self, request: web.Request):
-        method = request.method
-        if method == "PUT":
-            return await self._handle_route_put(request)
-        elif method == "GET":
-            return await self._handle_route_get(request)
-        else:
-            return web.Response(
-                text="Method not allowed", status=405, content_type="application/json"
-            )
-
-    async def _handle_route_put(self, request: web.Request):
-        data = await request.json()
-        role = data["role"]
-        rank_ip = data["rank_ip"]
-        rank_port = int(data["rank_port"])
-        engine_rank = int(data["engine_rank"])
-        agent_name = data["agent_name"]
-
-        if role == "Prefill":
-            async with self.lock:
-                self.prefill_port_table[engine_rank] = {
-                    "rank_ip": rank_ip,
-                    "rank_port": rank_port,
-                    "agent_name": agent_name,
-                }
-            logger.info(
-                f"Registered Prefill boostrap: {engine_rank} with rank_ip: {rank_ip} and rank_port: {rank_port} and name: {agent_name}"
-            )
-
-        return web.Response(text="OK", status=200)
-
-    async def _handle_route_get(self, request: web.Request):
-        engine_rank = request.query.get("engine_rank")
-        if not engine_rank:
-            logger.debug(
-                f"No engine_rank specified, return all {len(self.prefill_port_table)} engine infos as a dict"
-            )
-            # Return a dict of all engine_rank
-            async with self.lock:
-                bootstrap_info = self.prefill_port_table
-            return web.json_response(bootstrap_info, status=200)
-
-        # Find corresponding prefill info
-        async with self.lock:
-            bootstrap_info = self.prefill_port_table.get(int(engine_rank))
-        if bootstrap_info is not None:
-            return web.json_response(bootstrap_info, status=200)
-        else:
-            return web.Response(text="Not Found", status=404)
-
-    def _run_server(self):
-        try:
-            # Event Loop
-            self._loop = asyncio.new_event_loop()
-            asyncio.set_event_loop(self._loop)
-
-            self._runner = web.AppRunner(self.app)
-            self._loop.run_until_complete(self._runner.setup())
-
-            site = web.TCPSite(self._runner, port=self.port)
-            self._loop.run_until_complete(site.start())
-            self._loop.run_forever()
-        except Exception as e:
-            logger.error(f"Server error: {str(e)}")
-        finally:
-            # Cleanup
-            self._loop.run_until_complete(self._runner.cleanup())
-            self._loop.close()
-
-    def close(self):
-        """Shutdown"""
-        if self._loop is not None and self._loop.is_running():
-            self._loop.call_soon_threadsafe(self._loop.stop)
-            logger.info("Stopping server loop...")
-
-        if self.thread.is_alive():
-            self.thread.join(timeout=2)
-            logger.info("Server thread stopped")
-
-    def poll(self) -> KVPoll: ...

python/sglang/srt/disaggregation/utils.py

@@ -13,7 +13,7 @@ import requests
 import torch
 import torch.distributed as dist
 
-from sglang.srt.utils import get_ip
+from sglang.srt.utils import get_ip, get_local_ip_by_remote
 
 if TYPE_CHECKING:
     from sglang.srt.managers.schedule_batch import Req
@@ -279,3 +279,20 @@ class MetadataBuffers:
                 ] = torch.tensor(
                     req.output_top_logprobs_idx[0], dtype=torch.int32, device="cpu"
                 )
+
+
+def group_concurrent_contiguous(
+    src_indices: npt.NDArray[np.int64], dst_indices: npt.NDArray[np.int64]
+) -> Tuple[List[npt.NDArray[np.int64]], List[npt.NDArray[np.int64]]]:
+    """Vectorised NumPy implementation."""
+    if src_indices.size == 0:
+        return [], []
+
+    brk = np.where((np.diff(src_indices) != 1) | (np.diff(dst_indices) != 1))[0] + 1
+    src_groups = np.split(src_indices, brk)
+    dst_groups = np.split(dst_indices, brk)
+
+    src_groups = [g.tolist() for g in src_groups]
+    dst_groups = [g.tolist() for g in dst_groups]
+
+    return src_groups, dst_groups