我有以下简单的“Hello World”应用程序:
from gevent import monkey
monkey.patch_all()
from flask import Flask
from gevent import wsgi
app = Flask(__name__)
@app.route('/')
def index():
return 'Hello World'
server = wsgi.WSGIServer(('127.0.0.1', 5000), app)
server.serve_forever()
如您所见，它非常简单。
问题是，尽管如此简单，但它仍然非常缓慢/效率低下，如下面的基准测试(使用 Apache Benchmark 制作)所示:
ab -k -n 1000 -c 100 http://127.0.0.1:5000/
Benchmarking 127.0.0.1 (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests
Server Software:
Server Hostname: 127.0.0.1
Server Port: 5000
Document Path: /
Document Length: 11 bytes
Concurrency Level: 100
Time taken for tests: 1.515 seconds
Complete requests: 1000
Failed requests: 0
Write errors: 0
Keep-Alive requests: 0
Total transferred: 146000 bytes
HTML transferred: 11000 bytes
Requests per second: 660.22 [#/sec] (mean)
Time per request: 151.465 [ms] (mean)
Time per request: 1.515 [ms] (mean, across all concurrent requests)
Transfer rate: 94.13 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.6 0 3
Processing: 1 145 33.5 149 191
Waiting: 1 144 33.5 148 191
Total: 4 145 33.0 149 191
Percentage of the requests served within a certain time (ms)
50% 149
66% 157
75% 165
80% 173
90% 183
95% 185
98% 187
99% 188
100% 191 (longest request)
最终增加连接数和/或并发数并没有带来更好的结果，实际上它变得更糟。
我最担心的是我无法处理超过 700 个每秒请求 和 98 KB/秒的传输速率。
此外，单个每个请求的时间似乎太多了。
我很好奇 Python 和 Gevent 在后台做什么，或者更好的是，操作系统在做什么，所以我使用 strace 来确定最终的系统端问题，结果如下:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
56.46 0.000284 0 1386 close
24.25 0.000122 0 1016 write
10.74 0.000054 0 1000 send
4.17 0.000021 0 3652 3271 open
2.19 0.000011 0 641 read
2.19 0.000011 0 6006 fcntl64
0.00 0.000000 0 1 waitpid
0.00 0.000000 0 1 execve
0.00 0.000000 0 3 time
0.00 0.000000 0 12 12 access
0.00 0.000000 0 32 brk
0.00 0.000000 0 5 1 ioctl
0.00 0.000000 0 5006 gettimeofday
0.00 0.000000 0 4 2 readlink
0.00 0.000000 0 191 munmap
0.00 0.000000 0 1 1 statfs
0.00 0.000000 0 1 1 sigreturn
0.00 0.000000 0 2 clone
0.00 0.000000 0 2 uname
0.00 0.000000 0 21 mprotect
0.00 0.000000 0 69 65 _llseek
0.00 0.000000 0 71 rt_sigaction
0.00 0.000000 0 1 rt_sigprocmask
0.00 0.000000 0 3 getcwd
0.00 0.000000 0 1 getrlimit
0.00 0.000000 0 243 mmap2
0.00 0.000000 0 1838 748 stat64
0.00 0.000000 0 74 lstat64
0.00 0.000000 0 630 fstat64
0.00 0.000000 0 1 getuid32
0.00 0.000000 0 1 getgid32
0.00 0.000000 0 1 geteuid32
0.00 0.000000 0 1 getegid32
0.00 0.000000 0 4 getdents64
0.00 0.000000 0 3 1 futex
0.00 0.000000 0 1 set_thread_area
0.00 0.000000 0 2 epoll_ctl
0.00 0.000000 0 12 1 epoll_wait
0.00 0.000000 0 1 set_tid_address
0.00 0.000000 0 26 clock_gettime
0.00 0.000000 0 2 openat
0.00 0.000000 0 1 set_robust_list
0.00 0.000000 0 1 eventfd2
0.00 0.000000 0 1 epoll_create1
0.00 0.000000 0 1 pipe2
0.00 0.000000 0 1 socket
0.00 0.000000 0 1 bind
0.00 0.000000 0 1 listen
0.00 0.000000 0 1000 accept
0.00 0.000000 0 1 getsockname
0.00 0.000000 0 2000 1000 recv
0.00 0.000000 0 1 setsockopt
------ ----------- ----------- --------- --------- ----------------
100.00 0.000503 24977 5103 total
如您所见，有 5103 个错误，最严重的问题是 open syscall，我怀疑这与找不到文件有关 (ENOENT)。令我惊讶的是，epoll 看起来不像是一个麻烦，因为我听说过很多关于它的恐怖故事。
我希望发布完整的 strace，其中包含每个调用的详细信息，但它太大了。
最后一点；我还设置了以下系统参数(这是允许的最大数量)，希望它能改变这种情况，但事实并非如此:
echo “32768 61000″ > /proc/sys/net/ipv4/ip_local_port_range
sysctl -w fs.file-max=128000
sysctl -w net.ipv4.tcp_keepalive_time=300
sysctl -w net.core.somaxconn=61000
sysctl -w net.ipv4.tcp_max_syn_backlog=2500
sysctl -w net.core.netdev_max_backlog=2500
ulimit -n 1024
我的问题是，考虑到我使用的示例无法更改太多来解决这些问题，我应该去哪里纠正它们？
更新 我用 Wheezy.web 和 Gevent 制作了以下“Hello World”脚本，每秒收到约 2000 个请求:
from gevent import monkey
monkey.patch_all()
from gevent import pywsgi
from wheezy.http import HTTPResponse
from wheezy.http import WSGIApplication
from wheezy.routing import url
from wheezy.web.handlers import BaseHandler
from wheezy.web.middleware import bootstrap_defaults
from wheezy.web.middleware import path_routing_middleware_factory
def helloworld(request):
response = HTTPResponse()
response.write('hello world')
return response
routes = [
url('hello', helloworld, name='helloworld')
]
options = {}
main = WSGIApplication(
middleware=[
bootstrap_defaults(url_mapping=routes),
path_routing_middleware_factory
],
options=options
)
server = pywsgi.WSGIServer(('127.0.0.1', 5000), main, backlog=128000)
server.serve_forever()
基准测试结果:
ab -k -n 1000 -c 1000 http://127.0.0.1:5000/hello
Benchmarking 127.0.0.1 (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests
Server Software:
Server Hostname: 127.0.0.1
Server Port: 5000
Document Path: /front
Document Length: 11 bytes
Concurrency Level: 1000
Time taken for tests: 0.484 seconds
Complete requests: 1000
Failed requests: 0
Write errors: 0
Keep-Alive requests: 0
Total transferred: 170000 bytes
HTML transferred: 11000 bytes
Requests per second: 2067.15 [#/sec] (mean)
Time per request: 483.758 [ms] (mean)
Time per request: 0.484 [ms] (mean, across all concurrent requests)
Transfer rate: 343.18 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 8 10.9 0 28
Processing: 2 78 39.7 56 263
Waiting: 2 78 39.7 56 263
Total: 18 86 42.6 66 263
Percentage of the requests served within a certain time (ms)
50% 66
66% 83
75% 129
80% 131
90% 152
95% 160
98% 178
99% 182
100% 263 (longest request)
我发现 Wheezy.web 的速度很快，但我仍然喜欢使用 Flask，因为它更简单，使用起来更省时。
最佳答案
您使用的是什么 gevent 版本？尝试将您的软件堆栈简化到最低限度，并尝试他们在他们的 github 上的示例。
https://github.com/gevent/gevent/blob/master/examples/wsgiserver.py
您是否将基准测试与非 gevent 版本进行了比较？我已经使用这个库获得了显着的加速，所以我会进一步调查。
关于Python Flask Gevent 堆栈 - 简单的 "Hello World"应用程序在进行基准测试时显示效率低下，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23937117/