Files
AstrAI/astrai/inference/engine.py
T
ViperEkura e13fe53475 refactor: assemble inference engines through a shared composition root
- add build_engine() to astrai.inference.engine as the single load-place-wire path for InferenceEngine, accepting a checkpoint path or live model/tokenizer plus passthrough engine kwargs
- migrate the server lifespan, generate CLI, humaneval/ifeval evals, and all three demos to build_engine; app._create_engine collapses into a direct call
- export build_engine from astrai and astrai.inference
- parameterize the autoregressive demo with --prompt one-shot continuation plus model path and sampling knobs, exiting cleanly on !exit or EOF
- cover the composition root with unit tests for live-object assembly, kwargs passthrough, and argument validation
2026-09-03 22:16:56 +08:00

309 lines
9.5 KiB
Python

"""Unified inference engine for continuous batching."""
import asyncio
import gc
import logging
import threading
from pathlib import Path
from typing import Any, AsyncGenerator, Dict, Generator, List, Optional, Tuple, Union
import torch
import torch.nn as nn
from astrai.extension import ATTN_BACKEND, AttentionBackend, get_backend
from astrai.inference.cache import PagePool
from astrai.inference.scheduler import InferenceScheduler
from astrai.inference.task import STOP
from astrai.model import AutoModel
from astrai.tokenize import AutoTokenizer
logger = logging.getLogger(__name__)
class GenerateResult:
"""Thread-safe token accumulator for streaming and non-streaming modes."""
def __init__(self, count: int = 1):
self._cond = threading.Condition()
self._event = threading.Event()
self.tokens: List[Tuple[int, str]] = []
self.results: List[str] = [""] * count
self._done: List[bool] = [False] * count
self._completed = 0
self._total = count
def append(self, token: str, idx: int = 0):
with self._cond:
self.tokens.append((idx, token))
if token is not STOP:
self.results[idx] += token
else:
if not self._done[idx]:
self._done[idx] = True
self._completed += 1
self._cond.notify_all()
self._event.set()
def pop_all(self) -> List[Tuple[int, str]]:
with self._cond:
out = self.tokens.copy()
self.tokens.clear()
self._event.clear()
return out
def wait(self, timeout: Optional[float] = None) -> bool:
return self._event.wait(timeout=timeout)
def wait_completion(self, timeout: float = 300.0):
with self._cond:
if not self._cond.wait_for(
lambda: self._completed >= self._total, timeout=timeout
):
raise TimeoutError(
f"Generation timeout after {timeout}s "
f"({self._completed}/{self._total} completed)"
)
def get_results(self) -> List[str]:
with self._cond:
return self.results.copy()
class InferenceEngine:
"""Unified inference engine backed by continuous-batching scheduler."""
def __init__(
self,
model: nn.Module,
tokenizer: AutoTokenizer,
max_batch_size: int = 1,
max_seq_len: Optional[int] = None,
cache: Optional[PagePool] = None,
enable_cuda_graph: bool = True,
backend: Optional[Union[str, ATTN_BACKEND, AttentionBackend, type]] = None,
):
self.model = model
self.tokenizer = tokenizer
self.scheduler = InferenceScheduler(
model=self.model,
tokenizer=self.tokenizer,
max_batch_size=max_batch_size,
max_seq_len=max_seq_len,
cache=cache,
enable_cuda_graph=enable_cuda_graph,
backend=backend,
)
self.scheduler.start()
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.shutdown()
return False
def generate(
self,
prompt: Union[str, List[str]],
stream: bool = False,
max_tokens: Optional[int] = None,
temperature: float = 1.0,
top_p: float = 1.0,
top_k: int = 50,
frequency_penalty: float = 0.0,
rep_window: int = 64,
) -> Union[Generator, str, List[str]]:
is_batch = isinstance(prompt, list)
prompts = prompt if is_batch else [prompt]
if max_tokens is not None and max_tokens <= 0:
if stream:
return iter(())
results = [""] * len(prompts)
return results if is_batch else results[0]
return self._generate(
prompts,
is_batch,
stream,
max_tokens,
temperature,
top_p,
top_k,
frequency_penalty,
rep_window,
)
def generate_async(
self,
prompt: str,
max_tokens: Optional[int] = None,
temperature: float = 1.0,
top_p: float = 1.0,
top_k: int = 50,
frequency_penalty: float = 0.0,
rep_window: int = 64,
) -> AsyncGenerator[str, None]:
request_backend = get_backend(use_default=False)
result = GenerateResult()
task_id = self.scheduler.add_task(
prompt=prompt,
max_tokens=max_tokens,
temperature=temperature,
top_p=top_p,
top_k=top_k,
frequency_penalty=frequency_penalty,
rep_window=rep_window,
backend=request_backend,
stream_callback=result.append,
)
async def _agen():
finished = False
try:
while not finished:
for _idx, token in result.pop_all():
if token is STOP:
finished = True
break
yield token
if not finished:
await asyncio.to_thread(result.wait, 0.05)
finally:
if not finished:
self.scheduler.cancel_task(task_id)
return _agen()
def _generate(
self,
prompts: List[str],
is_batch: bool,
stream: bool,
max_tokens: Optional[int],
temperature: float,
top_p: float,
top_k: int,
frequency_penalty: float,
rep_window: int,
) -> Union[Generator, str, List[str]]:
n = len(prompts)
request_backend = get_backend(use_default=False)
result = GenerateResult(count=n)
task_ids = [
self.scheduler.add_task(
prompt=p,
max_tokens=max_tokens,
temperature=temperature,
top_p=top_p,
top_k=top_k,
frequency_penalty=frequency_penalty,
rep_window=rep_window,
backend=request_backend,
stream_callback=lambda token, idx=i: result.append(token, idx),
)
for i, p in enumerate(prompts)
]
if not stream:
try:
result.wait_completion()
except TimeoutError:
for tid in task_ids:
self.scheduler.cancel_task(tid)
raise
res = result.get_results()
return res if is_batch else res[0]
remaining = n
finished = [False] * n
def gen():
nonlocal remaining
try:
while remaining > 0:
items = result.pop_all()
for idx, token in items:
if token is STOP:
if not finished[idx]:
finished[idx] = True
remaining -= 1
else:
yield (idx, token) if is_batch else token
if remaining > 0:
result.wait(timeout=0.05)
finally:
for idx, task_id in enumerate(task_ids):
if not finished[idx]:
self.scheduler.cancel_task(task_id)
return gen()
def get_stats(self) -> Dict[str, Any]:
return self.scheduler.get_stats()
@property
def backend_name(self) -> str:
return self.scheduler.backend_name
@property
def cuda_graph_enabled(self) -> bool:
return self.scheduler.cuda_graph_enabled
def shutdown(self):
self.scheduler.stop()
if torch.cuda.is_available():
torch.cuda.empty_cache()
gc.collect()
def build_engine(
param_path: Optional[Union[str, Path]] = None,
*,
model: Optional[nn.Module] = None,
tokenizer: Optional[AutoTokenizer] = None,
device: Optional[str] = "cuda",
dtype: Optional[torch.dtype] = torch.bfloat16,
max_batch_size: int = 16,
max_seq_len: Optional[int] = None,
**engine_kwargs: Any,
) -> InferenceEngine:
"""Composition root for inference assembly.
Loads model and tokenizer from *param_path*, or accepts preloaded
objects, places the model, and returns a started InferenceEngine.
Extra *engine_kwargs* (cache, enable_cuda_graph, backend) pass
through to InferenceEngine. Placement parts left as None are skipped.
"""
if param_path is not None:
if model is not None or tokenizer is not None:
raise ValueError("pass either param_path or model+tokenizer, not both")
path = Path(param_path)
if not path.exists():
raise FileNotFoundError(f"Parameter directory not found: {path}")
tokenizer = AutoTokenizer.from_pretrained(path)
model = AutoModel.from_pretrained(path)
elif model is None or tokenizer is None:
raise ValueError("build_engine requires param_path or both model and tokenizer")
placement: Dict[str, Any] = {}
if device is not None:
placement["device"] = device
if dtype is not None:
placement["dtype"] = dtype
if placement:
model.to(**placement)
logger.info(
f"Model placed on {placement.get('device')} "
f"with dtype {placement.get('dtype')}"
)
return InferenceEngine(
model=model,
tokenizer=tokenizer,
max_batch_size=max_batch_size,
max_seq_len=max_seq_len,
**engine_kwargs,
)