演员任务执行顺序

同步, 单线程的 Actor

在 Ray 中，一个 actor 从多个提交者（包括驱动程序和工作线程）接收任务。对于从同一提交者接收的任务，一个同步的单线程 actor 按照提交顺序执行它们。换句话说，在同一提交者提交的先前任务完成执行之前，给定的任务不会被执行。

Python

import ray

@ray.remote
class Counter:
    def __init__(self):
        self.value = 0

    def add(self, addition):
        self.value += addition
        return self.value

counter = Counter.remote()

# For tasks from the same submitter,
# they are executed according to submission order.
value0 = counter.add.remote(1)
value1 = counter.add.remote(2)

# Output: 1. The first submitted task is executed first.
print(ray.get(value0))
# Output: 3. The later submitted task is executed later.
print(ray.get(value1))

1
3

然而，执行者不保证来自不同提交者的任务的执行顺序。例如，假设一个未满足的参数阻塞了一个先前提交的任务。在这种情况下，执行者仍然可以执行由不同工作者提交的任务。

Python

import time
import ray

@ray.remote
class Counter:
    def __init__(self):
        self.value = 0

    def add(self, addition):
        self.value += addition
        return self.value

counter = Counter.remote()

# Submit task from a worker
@ray.remote
def submitter(value):
    return ray.get(counter.add.remote(value))

# Simulate delayed result resolution.
@ray.remote
def delayed_resolution(value):
    time.sleep(5)
    return value

# Submit tasks from different workers, with
# the first submitted task waiting for
# dependency resolution.
value0 = submitter.remote(delayed_resolution.remote(1))
value1 = submitter.remote(2)

# Output: 3. The first submitted task is executed later.
print(ray.get(value0))
# Output: 2. The later submitted task is executed first.
print(ray.get(value1))

3
2

异步或线程化角色

异步或线程化角色 不保证任务执行顺序。这意味着系统可能会执行一个任务，即使之前提交的任务尚未执行。

Python

import time
import ray

@ray.remote
class AsyncCounter:
    def __init__(self):
        self.value = 0

    async def add(self, addition):
        self.value += addition
        return self.value

counter = AsyncCounter.remote()

# Simulate delayed result resolution.
@ray.remote
def delayed_resolution(value):
    time.sleep(5)
    return value

# Submit tasks from the driver, with
# the first submitted task waiting for
# dependency resolution.
value0 = counter.add.remote(delayed_resolution.remote(1))
value1 = counter.add.remote(2)

# Output: 3. The first submitted task is executed later.
print(ray.get(value0))
# Output: 2. The later submitted task is executed first.
print(ray.get(value1))

3
2