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ray-project--ray/python/ray/tune/tests/execution/test_actor_caching.py
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2026-07-13 13:17:40 +08:00

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4.4 KiB
Python

import sys
import pytest
import ray
from ray.tune import PlacementGroupFactory
from ray.tune.tests.execution.utils import TestingTrial, create_execution_test_objects
@pytest.fixture
def ray_start_2_cpus():
address_info = ray.init(num_cpus=2)
yield address_info
ray.shutdown()
def test_actor_cached(tmpdir, ray_start_2_cpus):
tune_controller, actor_manger, resource_manager = create_execution_test_objects(
max_pending_trials=8
)
assert not actor_manger.added_actors
tune_controller.add_trial(TestingTrial("trainable1", stub=True, trial_id="trial1"))
tune_controller.step()
tracked_actor, cls_name, kwargs = actor_manger.added_actors[0]
assert cls_name == "trainable1"
def test_actor_reuse_unstaged(tmpdir, ray_start_2_cpus):
"""A trial that hasn't been staged can re-use an actor.
In specific circumstances, this can lead to errors. Notably, when an
external source (e.g. a scheduler) directly calls TuneController APIs,
we can be in a situation where a trial has not been staged, but there is
still an actor available for it to use (because it hasn't been evicted from
the cache, yet).
This test constructs such a situation an asserts that actor re-use does not
lead to errors in those cases.
"""
tune_controller, actor_manger, resource_manager = create_execution_test_objects(
max_pending_trials=1
)
tune_controller._reuse_actors = True
assert not actor_manger.added_actors
trialA1 = TestingTrial(
"trainable1",
stub=True,
trial_id="trialA1",
placement_group_factory=PlacementGroupFactory([{"CPU": 1}]),
)
tune_controller.add_trial(trialA1)
trialB1 = TestingTrial(
"trainable1",
stub=True,
trial_id="trialB1",
placement_group_factory=PlacementGroupFactory([{"CPU": 5}]),
)
tune_controller.add_trial(trialB1)
trialA2 = TestingTrial(
"trainable1",
stub=True,
trial_id="trialA2",
placement_group_factory=PlacementGroupFactory([{"CPU": 1}]),
)
tune_controller.add_trial(trialA2)
tune_controller.step()
# Prevent trial A3 from being staged by setting the number
# of pending actors to the maximum allowed
actor_manger.set_num_pending(2)
trialA3 = TestingTrial(
"trainable1",
stub=True,
trial_id="trialA3",
placement_group_factory=PlacementGroupFactory([{"CPU": 1}]),
)
tune_controller.add_trial(trialA3)
tune_controller.step()
tracked_actorA1, _, _ = actor_manger.added_actors[0]
tracked_actorB1, _, _ = actor_manger.added_actors[1]
tracked_actorA2, _, _ = actor_manger.added_actors[2]
# Start trial A1, report that it's done training.
# This will cache the actor for A1 as A2 is already scheduled.
tune_controller._actor_started(tracked_actorA1)
tune_controller._on_training_result(trialA1, {"done": True})
# Trial A2 should be in the staged trials. A3 should still not be staged.
assert trialA2 in tune_controller._staged_trials
assert trialA3 not in tune_controller._staged_trials
# The actor of A1 should be cached for re-use now.
assert tune_controller._actor_cache.num_cached_objects == 1
# In the meantime, actor A2 started. This will unstage it.
tune_controller._actor_started(tracked_actorA2)
# Now, an external source (e.g. the BOHB scheduler) wants to prematurely
# stop trial A2. This will leave the cached actor intact, but trial A3
# is still not scheduled.
tune_controller._schedule_trial_stop(trialA2)
assert tune_controller._actor_cache.num_cached_objects == 1
# Process events. This will invoke "path 3" in TuneController._maybe_add_actors
# and re-use the cached actor
tune_controller.step()
# Reset future scheduled
assert actor_manger.scheduled_futures[-1][2] == "reset"
# Prior to https://github.com/ray-project/ray/pull/36951, there was a bug here:
# Because trial A3 was never staged, the unstage ran into an error.
# This fails without the line: self._staged_trials.add(start_trial)
tune_controller._on_trial_reset(trialA3, True)
# When the actor finally stops, the cache size is adjusted and the actor is
# evicted. This test failed without the line:
# self._actor_cache.increase_max(start_trial.placement_group_factory)
tune_controller._actor_stopped(tracked_actorA1)
tune_controller.step()
if __name__ == "__main__":
sys.exit(pytest.main(["-v", __file__]))