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

475 lines
17 KiB
Python

from __future__ import annotations
import asyncio
import dataclasses
import logging
import queue
import socket
import struct
import threading
import uuid
from collections import defaultdict
from functools import cache
from typing import Dict, List, Optional, Set, Tuple, TypeAlias, 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 BaseKVSender, KVArgs, KVPoll
from sglang.srt.disaggregation.common.conn import (
CommonKVBootstrapServer,
CommonKVManager,
CommonKVReceiver,
)
from sglang.srt.disaggregation.utils import (
DisaggregationMode,
group_concurrent_contiguous,
)
from sglang.srt.server_args import ServerArgs
from sglang.srt.utils import get_local_ip_by_remote
logger = logging.getLogger(__name__)
NixlEngineInfo: TypeAlias = Dict[str, Union[str, int]]
GUARD = "NixlMsgGuard".encode("ascii")
@dataclasses.dataclass
class TransferInfo:
room: int
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.dst_kv_indices.size == 0
@classmethod
def from_zmq(cls, msg: List[bytes]):
return cls(
room=int(msg[0].decode("ascii")),
endpoint=msg[1].decode("ascii"),
dst_port=int(msg[2].decode("ascii")),
agent_metadata=msg[3],
agent_name=msg[4].decode("ascii"),
dst_kv_ptrs=list(struct.unpack(f"{len(msg[5])//8}Q", msg[5])),
dst_kv_indices=np.frombuffer(msg[6], dtype=np.int64),
dst_aux_ptrs=list(struct.unpack(f"{len(msg[7])//8}Q", msg[7])),
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")),
)
@dataclasses.dataclass
class TransferStatus:
"""Used by KV Receiver to know when a transfer is done."""
# KV chunk IDs that have been received.
received_kvs: Set[int] = dataclasses.field(default_factory=set)
# Number of kv chunks to expect, will know this after last chunk is received.
num_kvs_expected: Optional[int] = None
# Whether aux data has been received.
received_aux: bool = False
def is_done(self):
if self.num_kvs_expected is None:
return False
return self.num_kvs_expected == len(self.received_kvs) and self.received_aux
class NixlKVManager(CommonKVManager):
def __init__(
self,
args: KVArgs,
disaggregation_mode: DisaggregationMode,
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:
raise ImportError(
"Please install NIXL by following the instructions at "
"https://github.com/ai-dynamo/nixl/blob/main/README.md "
"to run SGLang with NixlTransferEngine."
) from e
self.agent = nixl_agent(str(uuid.uuid4()))
self.server_socket = zmq.Context().socket(zmq.PULL)
self.register_buffer_to_engine()
if self.disaggregation_mode == DisaggregationMode.PREFILL:
self.request_status = {}
self.transfer_infos: Dict[int, TransferInfo] = {}
self.peer_names: Dict[str, str] = {}
self._start_bootstrap_thread()
elif self.disaggregation_mode == DisaggregationMode.DECODE:
self.transfer_statuses: Dict[int, TransferStatus] = defaultdict(
TransferStatus
)
else:
raise ValueError(
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(
self.kv_args.kv_data_ptrs, self.kv_args.kv_data_lens
):
kv_addrs.append((kv_data_ptr, kv_data_len, self.kv_args.gpu_id, ""))
self.kv_descs = self.agent.register_memory(kv_addrs, "VRAM", is_sorted=True)
logger.debug(f"Register kv tensors, len(kv_addr)= {len(kv_addrs)}")
if not self.kv_descs:
raise Exception("NIXL memory registration failed for kv tensors")
aux_addrs = []
for aux_data_ptr, aux_data_len in zip(
self.kv_args.aux_data_ptrs, self.kv_args.aux_data_lens
):
aux_addrs.append((aux_data_ptr, aux_data_len, 0, ""))
self.aux_descs = self.agent.register_memory(aux_addrs, "DRAM", is_sorted=True)
logger.debug(f"Register aux tensors, len(aux_addrs)= {len(aux_addrs)}")
if not self.aux_descs:
raise Exception("NIXL memory registration failed for aux tensors")
def _add_remote(self, agent_name: str, agent_metadata: bytes):
if agent_name not in self.peer_names:
self.peer_names[agent_name] = self.agent.add_remote_agent(agent_metadata)
return self.peer_names[agent_name]
def send_kvcache(
self,
peer_name: str,
prefill_kv_indices: npt.NDArray[np.int64],
dst_kv_ptrs: list[int],
dst_kv_indices: npt.NDArray[np.int64],
dst_gpu_id: int,
notif: str,
):
# group by indices
prefill_kv_blocks, dst_kv_blocks = group_concurrent_contiguous(
prefill_kv_indices, dst_kv_indices
)
logger.debug(f"sending kvcache to {peer_name} with notif {notif}")
# Make descs
num_layers = len(self.kv_args.kv_data_ptrs)
src_addrs = []
dst_addrs = []
for layer_id in range(num_layers):
src_ptr = self.kv_args.kv_data_ptrs[layer_id]
dst_ptr = dst_kv_ptrs[layer_id]
item_len = self.kv_args.kv_item_lens[layer_id]
for prefill_index, decode_index in zip(prefill_kv_blocks, dst_kv_blocks):
src_addr = src_ptr + int(prefill_index[0]) * item_len
dst_addr = dst_ptr + int(decode_index[0]) * item_len
length = item_len * len(prefill_index)
src_addrs.append((src_addr, length, self.kv_args.gpu_id))
dst_addrs.append((dst_addr, length, dst_gpu_id))
logger.debug(
f"len(src_addrs): before group: {len(prefill_kv_indices)}, after group: {len(src_addrs)}"
)
src_descs = self.agent.get_xfer_descs(src_addrs, "VRAM", is_sorted=True)
dst_descs = self.agent.get_xfer_descs(dst_addrs, "VRAM", is_sorted=True)
# Transfer data
xfer_handle = self.agent.initialize_xfer(
"WRITE",
src_descs,
dst_descs,
peer_name,
notif.encode("ascii"), # type: ignore
)
if not xfer_handle:
raise Exception("KVSender failed to create transfer")
state = self.agent.transfer(xfer_handle)
if state == "ERR":
raise Exception("KVSender failed to post transfer")
return xfer_handle
def send_aux(
self,
peer_name: str,
prefill_aux_index: int,
dst_aux_ptrs: list[int],
dst_aux_index: int,
notif: str,
):
# Make descs
aux_item_len = self.kv_args.aux_item_lens[0]
prefill_aux_addr = (
self.kv_args.aux_data_ptrs[0] + prefill_aux_index * aux_item_len
)
decode_aux_addr = dst_aux_ptrs[0] + dst_aux_index * aux_item_len
src_addrs = [(prefill_aux_addr, aux_item_len, 0)]
dst_addrs = [(decode_aux_addr, aux_item_len, 0)]
src_descs = self.agent.get_xfer_descs(src_addrs, "DRAM", is_sorted=True)
dst_descs = self.agent.get_xfer_descs(dst_addrs, "DRAM", is_sorted=True)
# Transfer data
xfer_handle = self.agent.initialize_xfer(
"WRITE",
src_descs,
dst_descs,
peer_name,
notif.encode("ascii"), # type: ignore
)
if not xfer_handle:
raise Exception("KVSender failed to create transfer")
state = self.agent.transfer(xfer_handle)
if state == "ERR":
raise Exception("KVSender failed to post transfer")
return xfer_handle
def add_transfer_request(
self,
bootstrap_room: int,
kv_indices: npt.NDArray[np.int64],
index_slice: slice,
is_last: bool,
chunk_id: int,
aux_index: Optional[int] = None,
):
assert self.disaggregation_mode == DisaggregationMode.PREFILL
assert not is_last or (is_last and aux_index is not None)
reqs_to_be_processed = self.transfer_infos[bootstrap_room].values()
handles = []
for req in reqs_to_be_processed:
assert bootstrap_room == req.room
if req.is_dummy():
continue
peer_name = self._add_remote(req.agent_name, req.agent_metadata)
chunked_dst_kv_indice = req.dst_kv_indices[index_slice]
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.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):
# Process notifications from received transfers.
notif_map = self.agent.get_new_notifs()
for peer_name, messages in notif_map.items():
# We could also check that self.bootstrap_info['agent_name'] matches
# the message sender. But the bootstrap room alone should be
# sufficient to map the status.
for msg in messages:
components = msg.decode("ascii").split("_")
room = int(components[0])
if components[1] == "kv":
chunk_id = int(components[2])
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
elif components[1] == "aux":
self.transfer_statuses[room].received_aux = True
def check_transfer_done(self, room: int):
if room not in self.transfer_statuses:
return False
return self.transfer_statuses[room].is_done()
def _start_bootstrap_thread(self):
self.server_socket.bind(f"tcp://{get_local_ip_by_remote()}:{self.rank_port}")
def bootstrap_thread():
"""This thread recvs transfer info from the decode engine"""
while True:
waiting_req_bytes = self.server_socket.recv_multipart()
logger.debug(
f"Received multipart with total byte size {sum(len(x) for x in waiting_req_bytes)}"
)
assert (
waiting_req_bytes[0] == GUARD
), f"First message should be {GUARD}. Foreign traffic?"
waiting_req_bytes = waiting_req_bytes[1:]
room = waiting_req_bytes[0].decode("ascii")
required_dst_info_num = int(waiting_req_bytes[10].decode("ascii"))
room = int(room)
agent_name = waiting_req_bytes[4].decode("ascii")
if room not in self.transfer_infos:
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()
class NixlKVSender(BaseKVSender):
def __init__(self, mgr: NixlKVManager, bootstrap_addr: str, bootstrap_room: int):
self.kv_mgr = mgr
self.bootstrap_room = bootstrap_room
self.aux_index = None
self.bootstrap_server_url = bootstrap_addr
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
self.aux_index = aux_index
def send(
self,
kv_indices: npt.NDArray[np.int64],
):
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,
index_slice,
is_last,
self.chunk_id,
self.aux_index,
)
self.xfer_handles.extend(new_xfer_handles)
self.chunk_id += 1
if is_last:
self.has_sent = True
def poll(self) -> KVPoll:
if not self.has_sent:
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
if any([x == "ERR" for x in states]):
raise Exception("KVSender transfer encountered an error.")
return KVPoll.WaitingForInput # type: ignore
def failure_exception(self):
raise Exception("Fake KVSender Exception")
class NixlKVReceiver(CommonKVReceiver):
def __init__(
self,
mgr: NixlKVManager,
bootstrap_addr: str,
bootstrap_room: Optional[int] = None,
):
self.started_transfer = False
super().__init__(mgr, bootstrap_addr, bootstrap_room)
def init(self, kv_indices: npt.NDArray[np.int64], aux_index: Optional[int] = None):
for bootstrap_info in self.bootstrap_infos:
self.prefill_server_url = (
f"{bootstrap_info['rank_ip']}:{bootstrap_info['rank_port']}"
)
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: 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
)
packed_aux_data_ptrs = b"".join(
struct.pack("Q", ptr) for ptr in self.kv_mgr.kv_args.aux_data_ptrs
)
logger.debug(
f"Sending to {self.prefill_server_url} with bootstrap room {self.bootstrap_room}"
)
sock, lock = self._connect("tcp://" + self.prefill_server_url)
with lock:
sock.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() if not is_dummy else b"",
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"),
]
)
self.started_transfer = True
def poll(self) -> KVPoll:
if not self.started_transfer:
return KVPoll.WaitingForInput # type: ignore
self.kv_mgr.update_transfer_status()
if self.kv_mgr.check_transfer_done(self.bootstrap_room): # type: ignore
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(CommonKVBootstrapServer):
pass