88 lines
3 KiB
Python
88 lines
3 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-only
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# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
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"""Single-GPU arbiter for Studio's heavy GPU consumers.
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The chat backends, diffusion, and video share one GPU. Before taking it each calls
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``acquire_for(owner)``, which evicts the current other owner so two large models never sit in VRAM
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at once. The arbiter only sequences ownership (freeing is each backend's teardown); eviction runs
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under the lock, so a transfer is atomic vs other acquires.
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"""
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from __future__ import annotations
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import threading
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from typing import Optional
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from loggers import get_logger
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logger = get_logger(__name__)
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CHAT = "chat"
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DIFFUSION = "diffusion"
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VIDEO = "video"
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_lock = threading.Lock()
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_owner: Optional[str] = None
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def _evict_chat() -> None:
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import time
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from core.inference import get_inference_backend
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from routes.inference import get_llama_cpp_backend
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llama = get_llama_cpp_backend()
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# is_active (process exists), not is_loaded (exists AND healthy): a chat model still starting
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# up holds VRAM but isn't healthy, so is_loaded would skip it and let the load race diffusion.
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if llama.is_active:
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llama.unload_model()
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orchestrator = get_inference_backend()
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if orchestrator.active_model_name:
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orchestrator.unload_model(orchestrator.active_model_name)
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# Kill the subprocess too: its base CUDA context holds VRAM diffusion needs.
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orchestrator._shutdown_subprocess(timeout = 5.0)
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# The driver reclaims the killed VRAM asynchronously; wait for it to settle before diffusion
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# allocates, else a warm chat->diffusion handoff can transiently OOM.
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llama._wait_for_vram_settle(since_kill = time.monotonic())
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def _evict_diffusion() -> None:
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# Unload whichever engine the router has active (diffusers or native sd.cpp), so a
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# chat acquire frees the right one.
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from core.inference.diffusion_engine_router import get_active_diffusion_engine
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get_active_diffusion_engine().unload()
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def _evict_video() -> None:
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from core.inference.video import get_video_backend
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get_video_backend().unload()
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# Patchable in tests via monkeypatch.setitem. Ownership is exclusive, so acquire_for's
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# evict-the-current-owner generalises to any number of registered owners.
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_EVICTORS = {CHAT: _evict_chat, DIFFUSION: _evict_diffusion, VIDEO: _evict_video}
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def acquire_for(owner: str) -> None:
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"""Make ``owner`` the sole GPU owner, evicting the other if it holds it."""
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global _owner
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if owner not in _EVICTORS:
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raise ValueError(f"unknown GPU owner: {owner!r}")
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with _lock:
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if _owner is not None and _owner != owner:
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logger.info("gpu_arbiter: evicting %s for %s", _owner, owner)
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_EVICTORS[_owner]()
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_owner = owner
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def release(owner: str) -> None:
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"""Drop ``owner``'s claim (no-op if it isn't the current owner)."""
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global _owner
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with _lock:
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if _owner == owner:
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_owner = None
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def current_owner() -> Optional[str]:
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return _owner
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