引子
之前clubot使用的pyxmpp2的默认mainloop也就是一个poll的主循环,但是clubot上线后资源占用非常厉害,使用strace跟踪发现clubot在不停的poll,查看pyxmpp2代码发现pyxmpp2的poll在使用超时阻塞时使用最小超时时间,而最小超时时间一直是0,所以会变成一个没有超时的非阻塞poll很浪费资源,不打算更改库代码,所以自己仿照poll的mainloop写了一个更加高效的epoll的mainloop
实现
#!/usr/bin/env python
# -*- coding:utf-8 -*-
#
# Author : cold
# E-mail : wh_linux@126.com
# Date : 13/01/06 10:41:31
# Desc : Clubot epoll mainloop
#
from __future__ import absolute_import, division
import select
from pyxmpp2.mainloop.interfaces import HandlerReady, PrepareAgain
from pyxmpp2.mainloop.base import MainLoopBase
from plugin.util import get_logger
class EpollMainLoop(MainLoopBase):
""" Main event loop based on the epoll() syscall on Linux system """
READ_ONLY = (select.EPOLLIN | select.EPOLLPRI | select.EPOLLHUP |
select.EPOLLERR |select.EPOLLET)
READ_WRITE = READ_ONLY | select.EPOLLOUT
def __init__(self, settings = None, handlers= None):
self.epoll = select.epoll()
self._handlers = {}
self._unprepared_handlers = {}
self._timeout = None
self._exists_fd = {}
self.logger = get_logger()
MainLoopBase.__init__(self, settings, handlers)
return
def _add_io_handler(self, handler):
self._unprepared_handlers[handler] = None
self._configure_io_handler(handler)
def _configure_io_handler(self, handler):
if self.check_events():
return
if handler in self._unprepared_handlers:
old_fileno = self._unprepared_handlers[handler]
prepared = self._prepare_io_handler(handler)
else:
old_fileno = None
prepared = True
fileno = handler.fileno()
if old_fileno is not None and fileno != old_fileno:
del self._handlers[old_fileno]
self._exists.pop(old_fileno, None)
self.epoll.unregister(old_fileno)
if not prepared:
self._unprepared_handlers[handler] = fileno
if not fileno:
return
self._handlers[fileno] = handler
events = 0
if handler.is_readable():
events |= self.READ_ONLY
if handler.is_writable():
events |= self.READ_WRITE
if events:
if fileno in self._exists_fd:
self.epoll.modify(fileno, events)
else:
self._exists_fd.update({fileno:1})
self.epoll.register(fileno, events)
def _prepare_io_handler(self, handler):
ret = handler.prepare()
if isinstance(ret, HandlerReady):
del self._unprepared_handlers[handler]
prepared = True
elif isinstance(ret, PrepareAgain):
if ret.timeout is not None:
if self._timeout is not None:
self._timeout = min(self._timeout, ret.timeout)
else:
self._timeout = ret.timeout
prepared = False
else:
raise TypeError("Unexpected result from prepare()")
return prepared
def _remove_io_handler(self, handler):
if handler in self._unprepared_handlers:
old_fileno = self._unprepared_handlers[handler]
del self._unprepared_handlers[handler]
else:
old_fileno = handler.fileno()
if old_fileno is not None:
try:
del self._handlers[old_fileno]
self._exists.pop(old_fileno, None)
self.epoll.unregister(old_fileno)
except KeyError:
pass
def loop_iteration(self, timeout = 60):
next_timeout, sources_handled = self._call_timeout_handlers()
if self.check_events():
return
if self._quit:
return sources_handled
for handler in list(self._unprepared_handlers):
self._configure_io_handler(handler)
if self._timeout is not None:
timeout = min(timeout, self._timeout)
if next_timeout is not None:
timeout = min(next_timeout, timeout)
if timeout == 0:
timeout += 1 # 带有超时的非阻塞,解约资源
events = self.epoll.poll(timeout)
for fd, flag in events:
if flag & (select.EPOLLIN | select.EPOLLPRI | select.EPOLLET):
self._handlers[fd].handle_read()
if flag & (select.EPOLLOUT|select.EPOLLET):
self._handlers[fd].handle_write()
if flag & (select.EPOLLERR | select.EPOLLET):
self._handlers[fd].handle_err()
if flag & (select.EPOLLHUP | select.EPOLLET):
self._handlers[fd].handle_hup()
#if flag & select.EPOLLNVAL:
#self._handlers[fd].handle_nval()
sources_handled += 1
self._configure_io_handler(self._handlers[fd])
return sources_handled
使用
如何使用新的mainloop?只需在实例化Client时传入
mainloop = EpollMainLoop(settings) client = Client(my_jid, [self, version_provider], settings, mainloop)
这样就会使用epoll作为mainloop
注意
epoll仅仅在Linux下支持
