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ray-project--ray/doc/source/ray-core/doc_code/scheduling.py
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2026-07-13 13:17:40 +08:00

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Python

import ray
ray.init(num_cpus=64)
# __default_scheduling_strategy_start__
@ray.remote
def func():
return 1
@ray.remote(num_cpus=1)
class Actor:
pass
# If unspecified, "DEFAULT" scheduling strategy is used.
func.remote()
actor = Actor.remote()
# Explicitly set scheduling strategy to "DEFAULT".
func.options(scheduling_strategy="DEFAULT").remote()
actor = Actor.options(scheduling_strategy="DEFAULT").remote()
# Zero-CPU (and no other resources) actors are randomly assigned to nodes.
actor = Actor.options(num_cpus=0).remote()
# __default_scheduling_strategy_end__
# __spread_scheduling_strategy_start__
@ray.remote(scheduling_strategy="SPREAD")
def spread_func():
return 2
@ray.remote(num_cpus=1)
class SpreadActor:
pass
# Spread tasks across the cluster.
[spread_func.remote() for _ in range(10)]
# Spread actors across the cluster.
actors = [SpreadActor.options(scheduling_strategy="SPREAD").remote() for _ in range(10)]
# __spread_scheduling_strategy_end__
# __node_affinity_scheduling_strategy_start__
@ray.remote
def node_affinity_func():
return ray.get_runtime_context().get_node_id()
@ray.remote(num_cpus=1)
class NodeAffinityActor:
pass
# Only run the task on the local node.
node_affinity_func.options(
scheduling_strategy=ray.util.scheduling_strategies.NodeAffinitySchedulingStrategy(
node_id=ray.get_runtime_context().get_node_id(),
soft=False,
)
).remote()
# Run the two node_affinity_func tasks on the same node if possible.
node_affinity_func.options(
scheduling_strategy=ray.util.scheduling_strategies.NodeAffinitySchedulingStrategy(
node_id=ray.get(node_affinity_func.remote()),
soft=True,
)
).remote()
# Only run the actor on the local node.
actor = NodeAffinityActor.options(
scheduling_strategy=ray.util.scheduling_strategies.NodeAffinitySchedulingStrategy(
node_id=ray.get_runtime_context().get_node_id(),
soft=False,
)
).remote()
# __node_affinity_scheduling_strategy_end__
# __locality_aware_scheduling_start__
@ray.remote
def large_object_func():
# Large object is stored in the local object store
# and available in the distributed memory,
# instead of returning inline directly to the caller.
return [1] * (1024 * 1024)
@ray.remote
def small_object_func():
# Small object is returned inline directly to the caller,
# instead of storing in the distributed memory.
return [1]
@ray.remote
def consume_func(data):
return len(data)
large_object = large_object_func.remote()
small_object = small_object_func.remote()
# Ray will try to run consume_func on the same node
# where large_object_func runs.
consume_func.remote(large_object)
# Ray will try to spread consume_func across the entire cluster
# instead of only running on the node where large_object_func runs.
[
consume_func.options(scheduling_strategy="SPREAD").remote(large_object)
for i in range(10)
]
# Ray won't consider locality for scheduling consume_func
# since the argument is small and will be sent to the worker node inline directly.
consume_func.remote(small_object)
# __locality_aware_scheduling_end__