优化简单服务器以支持多个客户端
我成功地实现了一个简单的服务器，可以同时处理多个客户端：
class ProcessingServer:
def __init__(self, bindaddress="127.0.0.1", portname=50001, maxqueue=5):
self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.socket.bind((bindaddress, portname))
self.socket.listen(maxqueue)
self.inputsocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.data = []
def start(self):
rsocks, wsocks = [], []
rsocks.append(self.socket)
rsocks.append(self.inputsocket)
print "Waiting for connection..."
self.inputsocket.connect(("192.168.1.1", 1234))
print "Connected."
clients = []
try:
while True:
try:
reads, writes, errs = select.select(rsocks, wsocks, [])
except:
return
for sock in reads:
if sock == self.socket:
client, address = sock.accept()
print "Client ", address, " connected"
wsocks.append(client)
clients.append(client)
elif sock == self.inputsocket:
self.data.append(sock.recv(256))
outstring = ""
if len(self.data) > 1:
msg_list = self.data[0].split('\n')
for msg in msg_list:
if msg != '':
curr_msg = msg.split(',')
process_message(curr_msg)
outstring = ','.join(curr_msg)
print curr_msg
self.data = []
for sock in writes:
if sock in clients:
if outstring != "":
sock.send(outstring)
except KeyboardInterrupt:
print "Server was stopped"
self.inputsocket.close()
self.socket.close()
for sock in writes:
sock.close()
for sock in reads:
sock.close()
for sock in clients:
sock.close()
process_message 这个函数只是添加了一些字段
一切运行得很好，但当客户端连接到服务器时，CPU的负载会飙升到100%。
这是客户端的代码：
import socket
mysocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysocket.connect(("127.0.0.1", 50001))
while True:
data = mysocket.recv(512)
mysocket.close()
outfile.close()
这里是性能分析的统计数据：
ncalls tottime percall cumtime percall filename:lineno(function)
1 0.000 0.000 34.563 34.563 <string>:1(<module>)
1 0.000 0.000 0.000 0.000 <string>:1(bind)
1 0.000 0.000 0.000 0.000 <string>:1(connect)
6870763 6.408 0.000 9.030 0.000 <string>:1(fileno)
1 0.000 0.000 0.000 0.000 <string>:1(listen)
1 0.000 0.000 0.000 0.000 server.py:113(__init__)
1 4.409 4.409 34.556 34.556 server.py:123(start)
1 0.007 0.007 34.563 34.563 server.py:176(main)
91 0.002 0.000 0.010 0.000 server.py:80(process_message)
3 0.000 0.000 0.000 0.000 socket.py:182(__init__)
1 0.000 0.000 0.000 0.000 socket.py:196(accept)
18 0.000 0.000 0.000 0.000 {getattr}
2290358 0.906 0.000 0.906 0.000 {len}
1 0.000 0.000 0.000 0.000 {method 'accept' of '_socket.socket' objects}
186 0.000 0.000 0.000 0.000 {method 'append' of 'list' objects}
1 0.000 0.000 0.000 0.000 {method 'bind' of '_socket.socket' objects}
1 0.000 0.000 0.000 0.000 {method 'connect' of '_socket.socket' objects}
1 0.000 0.000 0.000 0.000 {method 'disable' of '_lsprof.Profiler' objects}
6870763 2.622 0.000 2.622 0.000 {method 'fileno' of '_socket.socket' objects}
273 0.000 0.000 0.000 0.000 {method 'insert' of 'list' objects}
91 0.000 0.000 0.000 0.000 {method 'join' of 'str' objects}
1 0.000 0.000 0.000 0.000 {method 'listen' of '_socket.socket' objects}
182 0.001 0.000 0.001 0.000 {method 'recv' of '_socket.socket' objects}
71 0.001 0.000 0.001 0.000 {method 'send' of '_socket.socket' objects}
182 0.000 0.000 0.000 0.000 {method 'split' of 'str' objects}
2290268 20.197 0.000 29.227 0.000 {select.select}
18 0.000 0.000 0.000 0.000 {setattr}
这到底是怎么回事呢？
1 个回答
1
我建议你理解为，select 函数会返回一个可写的套接字。如果没有可读的套接字，而输出字符串保持为空 ''，那么你就会不停地重复这个循环，这样会导致 CPU 负担很重。所以，最好是只有在你确实需要写数据的时候，才把可写的套接字加入到列表中。这样，select 调用就会等到有数据可以读取的时候再继续。
关于你的评论，把：
reads, writes, errs = select.select(rsocks, wsocks, [])
替换为：
reads, writes, errs = select.select(rsocks, [], [])
并在 for sock in writes: 前面加上：
reads, writes, errs = select.select([], wsocks, [], 0)