Files
nano-vllm/nanovllm/engine/model_runner.py
GeeeekExplorer 03cfc13bb3 faster pickle
2025-06-23 00:51:52 +08:00

252 lines
11 KiB
Python

import pickle
import torch
import torch.distributed as dist
from multiprocessing.synchronize import Event
from multiprocessing.shared_memory import SharedMemory
from nanovllm.config import Config
from nanovllm.engine.sequence import Sequence
from nanovllm.models.qwen3 import Qwen3ForCausalLM
from nanovllm.layers.sampler import Sampler
from nanovllm.utils.context import set_context, get_context, reset_context
from nanovllm.utils.loader import load_model
class ModelRunner:
def __init__(self, config: Config, rank: int, event: Event | list[Event]):
self.config = config
hf_config = config.hf_config
self.block_size = config.kvcache_block_size
self.enforce_eager = config.enforce_eager
self.world_size = config.tensor_parallel_size
self.rank = rank
self.event = event
dist.init_process_group("nccl", "tcp://localhost:2333", world_size=self.world_size, rank=rank)
torch.cuda.set_device(rank)
default_dtype = torch.get_default_dtype()
torch.set_default_dtype(hf_config.torch_dtype)
torch.set_default_device("cuda")
self.model = Qwen3ForCausalLM(hf_config)
load_model(self.model, config.model)
self.sampler = Sampler()
self.allocate_kv_cache(config.gpu_memory_utilization)
if not self.enforce_eager:
self.capture_cudagraph()
torch.set_default_device("cpu")
torch.set_default_dtype(default_dtype)
if self.world_size > 1:
if rank == 0:
self.shm = SharedMemory(name="nanovllm", create=True, size=2**20)
dist.barrier()
else:
dist.barrier()
self.shm = SharedMemory(name="nanovllm")
self.loop()
def exit(self):
if self.world_size > 1:
self.shm.close()
dist.barrier()
if self.rank == 0:
self.shm.unlink()
if not self.enforce_eager:
del self.graphs, self.graph_pool
torch.cuda.synchronize()
dist.destroy_process_group()
def loop(self):
while True:
method_name, args = self.read_shm()
self.call(method_name, *args)
if method_name == "exit":
break
def read_shm(self):
assert self.world_size > 1 and self.rank
self.event.wait()
n = int.from_bytes(self.shm.buf[0:4], "little")
method_name, *args = pickle.loads(self.shm.buf[4:n+4])
self.event.clear()
return method_name, args
def write_shm(self, method_name, *args):
assert self.world_size > 1 and not self.rank
data = pickle.dumps([method_name, *args])
n = len(data)
assert n + 4 <= self.shm.size
self.shm.buf[0:4] = n.to_bytes(4, "little")
self.shm.buf[4:n+4] = data
for event in self.event:
event.set()
def call(self, method_name, *args):
if self.world_size > 1 and self.rank == 0:
self.write_shm(method_name, *args)
method = getattr(self, method_name, None)
assert callable(method)
return method(*args)
def allocate_kv_cache(self, gpu_memory_utilization):
config = self.config
hf_config = config.hf_config
free, total = torch.cuda.mem_get_info()
used = total - free
num_kv_heads = hf_config.num_key_value_heads // self.world_size
block_bytes = 2 * hf_config.num_hidden_layers * self.block_size * num_kv_heads * hf_config.head_dim * hf_config.torch_dtype.itemsize
config.num_kvcache_blocks = int(total * gpu_memory_utilization - used) // block_bytes
self.kv_cache = torch.zeros(2, hf_config.num_hidden_layers, config.num_kvcache_blocks, self.block_size, num_kv_heads, hf_config.head_dim)
layer_id = 0
for module in self.model.modules():
if hasattr(module, "k_cache") and hasattr(module, "v_cache"):
module.k_cache = self.kv_cache[0, layer_id]
module.v_cache = self.kv_cache[1, layer_id]
layer_id += 1
def prepare_block_tables(self, seqs: list[Sequence]):
max_len = max(len(seq.block_table) for seq in seqs)
block_tables = [
seq.block_table + [-1] * (max_len - len(seq.block_table))
for seq in seqs
]
block_tables = torch.tensor(block_tables, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
return block_tables
def prepare_prefill(self, seqs: list[Sequence]):
input_ids = []
positions = []
cu_seqlens_q = [0]
cu_seqlens_k = [0]
max_seqlen_q = 0
max_seqlen_k = 0
slot_mapping = []
block_tables = None
for seq in seqs:
seqlen = len(seq)
input_ids.extend(seq[seq.num_cached_tokens:])
positions.extend(list(range(seq.num_cached_tokens, seqlen)))
seqlen_q = seqlen - seq.num_cached_tokens
seqlen_k = seqlen
cu_seqlens_q.append(cu_seqlens_q[-1] + seqlen_q)
cu_seqlens_k.append(cu_seqlens_k[-1] + seqlen_k)
max_seqlen_q = max(seqlen_q, max_seqlen_q)
max_seqlen_k = max(seqlen_k, max_seqlen_k)
for i in range(seq.num_cached_blocks, seq.num_blocks):
start = seq.block_table[i] * self.block_size
if i != seq.num_blocks - 1:
end = start + self.block_size
else:
end = start + seq.last_block_num_tokens
slot_mapping.extend(list(range(start, end)))
assert len(input_ids) == len(slot_mapping)
if cu_seqlens_k[-1] > cu_seqlens_q[-1]: # prefix cache
block_tables = self.prepare_block_tables(seqs)
input_ids = torch.tensor(input_ids, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
positions = torch.tensor(positions, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
cu_seqlens_q = torch.tensor(cu_seqlens_q, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
cu_seqlens_k = torch.tensor(cu_seqlens_k, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
slot_mapping = torch.tensor(slot_mapping, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
set_context(True, cu_seqlens_q, cu_seqlens_k, max_seqlen_q, max_seqlen_k, slot_mapping, None, block_tables)
return input_ids, positions
def prepare_decode(self, seqs: list[Sequence]):
input_ids = []
positions = []
slot_mapping = []
context_lens = []
for seq in seqs:
input_ids.append(seq.last_token)
positions.append(len(seq))
context_lens.append(len(seq))
slot_mapping.append(seq.block_table[-1] * self.block_size + seq.last_block_num_tokens - 1)
input_ids = torch.tensor(input_ids, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
positions = torch.tensor(positions, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
slot_mapping = torch.tensor(slot_mapping, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
context_lens = torch.tensor(context_lens, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
block_tables = self.prepare_block_tables(seqs)
set_context(False, slot_mapping=slot_mapping, context_lens=context_lens, block_tables=block_tables)
return input_ids, positions
def prepare_sample(self, seqs: list[Sequence]):
temperatures = []
for seq in seqs:
temperatures.append(seq.temperature)
temperatures = torch.tensor(temperatures, dtype=torch.float32, pin_memory=True).cuda(non_blocking=True)
return temperatures
@torch.inference_mode()
def run_model(self, input_ids: torch.Tensor, positions: torch.Tensor, is_prefill):
if is_prefill or self.enforce_eager or input_ids.size(0) > 512:
return self.model.compute_logits(self.model(input_ids, positions))
else:
bs = input_ids.size(0)
context = get_context()
graph = self.graphs[next(x for x in self.graph_bs if x >= bs)]
graph_vars = self.graph_vars
for k, v in graph_vars.items():
if k != "outputs":
v.zero_()
graph_vars["input_ids"][:bs] = input_ids
graph_vars["positions"][:bs] = positions
graph_vars["slot_mapping"][:bs] = context.slot_mapping
graph_vars["context_lens"][:bs] = context.context_lens
graph_vars["block_tables"][:bs, :context.block_tables.size(1)] = context.block_tables
graph.replay()
return self.model.compute_logits(graph_vars["outputs"][:bs])
def run(self, seqs: list[Sequence], is_prefill: bool) -> list[int]:
input_ids, positions = self.prepare_prefill(seqs) if is_prefill else self.prepare_decode(seqs)
temperatures = self.prepare_sample(seqs) if self.rank == 0 else None
logits = self.run_model(input_ids, positions, is_prefill)
token_ids = self.sampler(logits, temperatures).tolist() if self.rank == 0 else None
reset_context()
return token_ids
@torch.inference_mode()
def capture_cudagraph(self):
get_rng_state = torch.cuda.get_rng_state
set_rng_state = torch.cuda.set_rng_state
rng_state = torch.cuda.get_rng_state()
torch.cuda.get_rng_state = lambda: rng_state
torch.cuda.set_rng_state = lambda _: None
config = self.config
hf_config = config.hf_config
max_bs = min(self.config.max_num_seqs, 512)
max_num_blocks = (config.max_model_len + self.block_size - 1) // self.block_size
input_ids = torch.zeros(max_bs, dtype=torch.int64)
positions = torch.zeros(max_bs, dtype=torch.int64)
slot_mapping = torch.zeros(max_bs, dtype=torch.int32)
context_lens = torch.zeros(max_bs, dtype=torch.int32)
block_tables = torch.zeros(max_bs, max_num_blocks, dtype=torch.int32)
outputs = torch.zeros(max_bs, hf_config.hidden_size)
self.graph_bs = [1, 2, 4, 8] + list(range(16, max_bs + 1, 16))
self.graphs = {}
self.graph_pool = None
for bs in reversed(self.graph_bs):
graph = torch.cuda.CUDAGraph()
set_context(False, slot_mapping=slot_mapping[:bs], context_lens=context_lens[:bs], block_tables=block_tables[:bs])
outputs[:bs] = self.model(input_ids[:bs], positions[:bs]) # warmup
with torch.cuda.graph(graph, self.graph_pool):
outputs[:bs] = self.model(input_ids[:bs], positions[:bs]) # capture
if self.graph_pool is None:
self.graph_pool = graph.pool()
self.graphs[bs] = graph
torch.cuda.synchronize()
reset_context()
self.graph_vars = dict(
input_ids=input_ids,
positions=positions,
slot_mapping=slot_mapping,
context_lens=context_lens,
block_tables=block_tables,
outputs=outputs,
)
torch.cuda.get_rng_state = get_rng_state
torch.cuda.set_rng_state = set_rng_state