unsloth/studio/backend/tests/test_gpu_arbiter.py

106 lines
3.1 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
"""Unit tests for the single-GPU arbiter.
The real evictors (which tear down live backends) are replaced with recorders, so
these verify only the ownership/eviction sequencing — no torch, GPU, or subprocess.
"""
from __future__ import annotations
import pytest
import core.inference.gpu_arbiter as arb
@pytest.fixture
def calls(monkeypatch):
recorded: list[str] = []
monkeypatch.setattr(arb, "_owner", None)
monkeypatch.setitem(arb._EVICTORS, arb.CHAT, lambda: recorded.append("evict-chat"))
monkeypatch.setitem(arb._EVICTORS, arb.DIFFUSION, lambda: recorded.append("evict-diffusion"))
return recorded
def test_first_acquire_evicts_nothing(calls):
arb.acquire_for(arb.CHAT)
assert calls == []
assert arb.current_owner() == arb.CHAT
def test_diffusion_load_evicts_chat(calls):
arb.acquire_for(arb.CHAT)
arb.acquire_for(arb.DIFFUSION)
assert calls == ["evict-chat"]
assert arb.current_owner() == arb.DIFFUSION
def test_chat_load_evicts_diffusion(calls):
arb.acquire_for(arb.DIFFUSION)
arb.acquire_for(arb.CHAT)
assert calls == ["evict-diffusion"]
assert arb.current_owner() == arb.CHAT
def test_reacquiring_same_owner_does_not_evict(calls):
arb.acquire_for(arb.CHAT)
arb.acquire_for(arb.CHAT)
assert calls == []
assert arb.current_owner() == arb.CHAT
def test_release_clears_owner(calls):
arb.acquire_for(arb.DIFFUSION)
arb.release(arb.DIFFUSION)
assert arb.current_owner() is None
# A subsequent chat load then has nothing to evict.
arb.acquire_for(arb.CHAT)
assert calls == []
def test_release_by_non_owner_is_noop(calls):
arb.acquire_for(arb.CHAT)
arb.release(arb.DIFFUSION)
assert arb.current_owner() == arb.CHAT
def test_unknown_owner_raises(calls):
with pytest.raises(ValueError):
arb.acquire_for("gpu")
def test_evict_chat_unloads_a_still_loading_chat_backend(monkeypatch):
# A chat model still starting up is is_active (process exists) but not yet
# is_loaded (healthy). Eviction must still unload it, or the load would keep
# allocating VRAM after the GPU was handed to diffusion.
import core.inference as core_inference
import routes.inference as routes_inference
unloaded: list[bool] = []
class _FakeLlama:
is_active = True
is_loaded = False # still loading: skipped if eviction gates on is_loaded
def unload_model(self):
unloaded.append(True)
def _wait_for_vram_settle(self, *, since_kill):
pass
class _FakeOrchestrator:
active_model_name = None
def unload_model(self, name):
pass
def _shutdown_subprocess(self, timeout = 5.0):
pass
monkeypatch.setattr(routes_inference, "get_llama_cpp_backend", lambda: _FakeLlama())
monkeypatch.setattr(core_inference, "get_inference_backend", lambda: _FakeOrchestrator())
arb._evict_chat()
assert unloaded == [True] # still-loading chat backend was unloaded, not skipped