如何使用asyncio减少ProcessPoolExecutor的cpu使用率？

Question

我使用ProcessPoolExecutor如下所示

def main(argv):
    set_argv(argv)
    # running code. Loop button click, enter text, submit.
if __name__ == '__main__':
    executer = ProcessPoolExecutor(max_workers=9)
    argvs = ["D", "E", "F", "G", "H", "I", "J", "K", "L"]
    for argv in argvs:
        executer.submit(main,argv)

但是这段代码使用CPU 100％，每个进程只需要两倍的时间来完成一个进程。

所以我想使用asyncio来降低CPU使用率。 但是下面的代码会产生错误。

async def async_set():
    coroutines = []
    argvs = ["D", "E", "F", "G", "H", "I", "J", "K", "L"]
    fts = [loop.run_in_executor(main(m)) for m in argvs]
    for f in asyncio.as_completed(fts, loop=loop):
        await f

async def main(argv):
    set_argv(argv)
    # running code. Loop button click, enter text, submit.

loop = asyncio.get_event_loop()
    loop.run_until_complete(async_set())
    loop.close()

错误是：

 fts = [loop.run_in_executor(main(m)) for m in argvs]
TypeError: run_in_executor() missing 1 required positional argument: 'func'

ㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡㅡ

改变之后的fts如下

fts = [loop.run_in_executor(None, main, m) for m in argvs]

出现错误， 但只有1个进程正常运行

Traceback (most recent call last):
  File "C:/Users/admin/Desktop/test/Version/test.py", line 593, in <module>
    loop.run_until_complete(async_set())
  File "C:\Python\Python37\lib\asyncio\base_events.py", line 584, in run_until_complete
    return future.result()
  File "C:/Users/admin/Desktop/test/Version/test.py", line 60, in async_set
    await f
  File "C:\Python\Python37\lib\asyncio\tasks.py", line 533, in _wait_for_one
    return f.result()  # May raise f.exception().
  File "C:\Python\Python37\lib\concurrent\futures\thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "C:/Users/admin/Desktop/test/Version/test.py", line 67, in main
    set_login(ID, PW)
  File "C:/Users/admin/Desktop/test/Version/test.py", line 188, in set_login
    driver.find_element_by_xpath('//*[@id="header"]/div/div[1]/ul[2]/li[1]/a').click()
  File "C:\Python\Python37\lib\site-packages\selenium\webdriver\remote\webelement.py", line 80, in click
    self._execute(Command.CLICK_ELEMENT)
  File "C:\Python\Python37\lib\site-packages\selenium\webdriver\remote\webelement.py", line 633, in _execute
    return self._parent.execute(command, params)
  File "C:\Python\Python37\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 321, in execute
    self.error_handler.check_response(response)
  File "C:\Python\Python37\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.StaleElementReferenceException: Message: stale element reference: element is not attached to the page document
  (Session info: chrome=73.0.3683.86)
  (Driver info: chromedriver=73.0.3683.68 (47787ec04b6e38e22703e856e101e840b65afe72),platform=Windows NT 10.0.17763 x86_64)

Answer 1

我不知道这模仿你的过程有多好，但这运行：

import asyncio
import concurrent.futures

def main(argv):
    t = random.choice([.02,.1,.5,.3,1.0,2.0,3.0,5.,6.,7.,8.,9.])
    time.sleep(t)
    return (t, argv * 2)

async def async_set():
    loop = asyncio.get_event_loop()
##    coroutines = []
    argvs = ["D", "E", "F", "G", "H", "I", "J", "K", "L"]
    with concurrent.futures.ProcessPoolExecutor() as pool:
        stuff = [loop.run_in_executor(pool,main,arg) for arg in argvs]
        for fut in asyncio.as_completed(stuff):
            print(await fut)

if __name__ == '__main__':

    loop = asyncio.get_event_loop()
    loop.run_until_complete(async_set())
    loop.close()

>>>
(0.5, 'EE')
(0.5, 'DD')
(0.5, 'FF')
(7.0, 'HH')
(8.0, 'II')
(0.1, 'LL')
(9.0, 'GG')
(9.0, 'JJ')
(7.0, 'KK')
>>>