Question

我在下面的测试脚本中创建了一个corolocal.local，以查找corolocal.local中的元素何时被垃圾收集。但目前还不是很清楚。当第二个线程为其分配另一个值时，第一个线程中实例化的TL.it被垃圾收集。但我徘徊谁在什么时候做了gc.collect（），是否与之相关 greenlet运行范围？我曾经发现有时会在mainloop greenlet中收集TL.it，有时会收集另一个greenlet，这会在我的程序中引起问题。例如，如果我在__del __（）方法中执行hub.switch（），它将报告错误＆＃34;无法从MAINLOOP切换到MAINLOOP＆＃34;。

import gc
import threading
from eventlet import hubs
from eventlet import event
import greenlet

import eventlet
eventlet.monkey_patch(all=True)


class InsideLocal(object):
    def __init__(self, td):
        self.td = td

    def __del__(self):
        print("Current greenlet inside %s: %s" %
              (self.td, greenlet.getcurrent()))
        print("Got deleted inside %s" % self.td)


class OutSideLocal(object):
    def __init__(self, td):
        self.td = td

    def __del__(self):
        print("Current greenlet outside %s: %s" %
              (self.td, greenlet.getcurrent()))
        print("Got deleted outside %s" % self.td)

TL = threading.local()


def play_insidethread(td, e):
    global TL
    TL.it = InsideLocal(td)
    ot = OutSideLocal(td)
    e.wait()
    print("Quiting thread %s" % td)

print("====Starting first thread====")
e = event.Event()
gt = eventlet.spawn(play_insidethread, 'first', e)

print("Primary greenlet: %s" % hubs.get_hub().greenlet)

# try to trigger gc for objects inside corolocal.local
# but here failed.
print("====Stopping first thread====")
e.send()
eventlet.sleep(0)

print("====Deleting greenthread object====")
# failed again
del gt
eventlet.sleep(0)

# failed again.
print("====Doing gc manually====")
print("gc %s" % gc.collect())
eventlet.sleep(0)

print("====Multi thread test====")
# succeeded.
events = []
for i in range(3):
    e = event.Event()
    events.append(e)
    eventlet.spawn(play_insidethread, i, e)

for e in events:
    e.send()
    eventlet.sleep(1)

print("====Quiting test====")
quit = event.Event()
quit.wait()

输出：

====Starting first thread====
Primary greenlet: <greenlet.greenlet object at 0x8c32d0>
====Stopping first thread====
Quiting thread first
Current greenlet outside first: <eventlet.greenthread.GreenThread object at 0x8c3370>
Got deleted outside first
====Deleting greenthread object====
====Doing gc manually====
gc 0
====Multi thread test====
Current greenlet inside first: <eventlet.greenthread.GreenThread object at 0x8c3370>
Got deleted inside first
Quiting thread 0
Current greenlet outside 0: <eventlet.greenthread.GreenThread object at 0x8c3370>
Got deleted outside 0
Current greenlet inside 0: <eventlet.greenthread.GreenThread object at 0x8c3410>
Got deleted inside 0
Quiting thread 1
Current greenlet outside 1: <eventlet.greenthread.GreenThread object at 0x8c3410>
Got deleted outside 1
Current greenlet inside 1: <greenlet.greenlet object at 0x8c32d0>
Got deleted inside 1
Quiting thread 2
Current greenlet outside 2: <eventlet.greenthread.GreenThread object at 0x8c34b0>
Got deleted outside 2
====Quiting test====

编辑：

我已阅读this article，但我没有得到答案。根据该文章的内容，每次访问一个对象（创建，删除等）时，python解释器将尝试进行一次垃圾收集，并在必要时从内存中删除一些对象。这不能解释我的测试结果，实际上在threading.local（）中的对象而不是threading.local（）中的对象表现不同。不在threading.local（）中的对象在mainloop运行时永远不会被删除，但是threading.local（）中的对象会被删除。

gc如何在python中使用eventlet（greenlet）？

0 个答案: