Question

在this Gevent tutorial中，介绍了如何产生多个线程以异步运行。

import gevent
import random

def task(pid):
    """
    Some non-deterministic task
    """
    gevent.sleep(random.randint(0,2)*0.001)
    print('Task %s done' % pid)

def synchronous():
    for i in range(1,10):
        task(i)

def asynchronous():
    threads = [gevent.spawn(task, i) for i in xrange(10)]
    gevent.joinall(threads)

print('Synchronous:')
synchronous()

print('Asynchronous:')
asynchronous()

结果

Synchronous:
Task 1 done
Task 2 done
Task 3 done
Task 4 done
Task 5 done
Task 6 done
Task 7 done
Task 8 done
Task 9 done
Asynchronous:
Task 1 done
Task 5 done
Task 6 done
Task 2 done
Task 4 done
Task 7 done
Task 8 done
Task 9 done
Task 0 done
Task 3 done

这符合我的预期。但是，当我将琐碎的睡眠任务替换为“工作”任务时，它的工作方式就不同...

import gevent
import random

def task(pid):
    start_time = time.time()
    array = []
    for x in range(0, 1000000):
        x = str(x) + "WasteMyTime"
        array.append(x)
    elapsed_time = time.time() - start_time
    print("Task " + str(pid) + " took  " + str(elapsed_time))

def synchronous():
    for i in range(1,10):
        task(i)

def asynchronous():
    threads = [gevent.spawn(task, i) for i in range(10)]
    gevent.joinall(threads)

print('Synchronous:')
synchronous()

print('Asynchronous:')
asynchronous()

结果

Synchronous:
Task 1 took  0.3065943717956543
Task 2 took  0.2897024154663086
Task 3 took  0.29267001152038574
Task 4 took  0.2936718463897705
Task 5 took  0.28526878356933594
Task 6 took  0.29134082794189453
Task 7 took  0.28323960304260254
Task 8 took  0.28522467613220215
Task 9 took  0.28423142433166504
Asynchronous:
Task 0 took  0.2896885871887207
Task 1 took  0.2837369441986084
Task 2 took  0.28224802017211914
Task 3 took  0.2857201099395752
Task 4 took  0.28621697425842285
Task 5 took  0.28621697425842285
Task 6 took  0.28621602058410645
Task 7 took  0.2857208251953125
Task 8 took  0.28720879554748535
Task 9 took  0.2847275733947754

每个异步任务都一个接一个地缓慢地打印出来，整个异步块花费的时间与同步块一样长。这是用户错误吗？

Answer 1

将此添加到脚本顶部（脚本的第一行）

from gevent import monkey; monkey.patch_all()

Gevent函数不是异步运行

1 个答案: