unsloth/studio/backend/core/inference/gpu_arbiter.py
2026-06-23 00:39:36 -03:00

78 lines
2.3 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""Single-GPU arbiter for Studio's two heavy GPU consumers.
The chat backends (llama-server + the Unsloth subprocess) and the diffusion
backend share one GPU. Before either takes the GPU it calls ``acquire_for(owner)``,
which evicts the current *other* owner so two large models never sit in VRAM at
once. The arbiter only sequences ownership; the actual freeing is delegated to
each backend's existing teardown.
Eviction runs under the arbiter lock, so an ownership transfer is atomic with
respect to other acquires.
"""
from __future__ import annotations
import threading
from typing import Optional
from loggers import get_logger
logger = get_logger(__name__)
CHAT = "chat"
DIFFUSION = "diffusion"
_lock = threading.Lock()
_owner: Optional[str] = None
def _evict_chat() -> None:
from core.inference import get_inference_backend
from routes.inference import get_llama_cpp_backend
llama = get_llama_cpp_backend()
if llama.is_loaded:
llama.unload_model()
orchestrator = get_inference_backend()
if orchestrator.active_model_name:
orchestrator.unload_model(orchestrator.active_model_name)
# Kill the subprocess too, not just the model: its base CUDA context holds
# VRAM the diffusion pipeline needs.
orchestrator._shutdown_subprocess(timeout = 5.0)
def _evict_diffusion() -> None:
from core.inference.diffusion import get_diffusion_backend
get_diffusion_backend().unload()
# Patchable in tests via monkeypatch.setitem.
_EVICTORS = {CHAT: _evict_chat, DIFFUSION: _evict_diffusion}
def acquire_for(owner: str) -> None:
"""Make ``owner`` the sole GPU owner, evicting the other if it holds it."""
global _owner
if owner not in _EVICTORS:
raise ValueError(f"unknown GPU owner: {owner!r}")
with _lock:
if _owner is not None and _owner != owner:
logger.info("gpu_arbiter: evicting %s for %s", _owner, owner)
_EVICTORS[_owner]()
_owner = owner
def release(owner: str) -> None:
"""Drop ``owner``'s claim (no-op if it isn't the current owner)."""
global _owner
with _lock:
if _owner == owner:
_owner = None
def current_owner() -> Optional[str]:
return _owner