On Fri, 2005-03-18 at 17:37 -0500, Stas Bekman wrote: > Anders, the first priority is to figure out how to reproduce the problem > at will. If you don't manage that, you most likely are going to waste > hours staring at the screen. I'd concentrate on that task first. > > Try using ab (apachebench), httpd_load or another utility to stress test. > More advanced tools can record and reply real requests. For some examples see: > http://modperlbook.org/html/ch09_01.html#pmodperl-CHP-9-SECT-1 > > Armed with one of these tools you can know exactly how many requests > you've issued and then making sure that logs/access_log is in agreement. > > Also take a look at Apache::Resource which can set certain limits on the > process resource consumption. >
I have been doing some testing with ab and I found some interesting cases. On our production system I get the following when testing an important mod_perl enabled script from my local desktop: $ ab -n 100 -c 5 "http://www.xxxxxx.dk/cgi/xxxxxx.cgi?q=test&allowall=1"; This is ApacheBench, Version 2.0.40-dev <$Revision: 1.121.2.1 $> apache-2.0 Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Copyright (c) 1998-2002 The Apache Software Foundation, http://www.apache.org/ Benchmarking www.xxxxxx.dk (be patient).....done Server Software: Apache/1.3.33 Server Hostname: www.xxxxxx.dk Server Port: 80 Document Path: /cgi/xxxxxx.cgi?q=test&allowall=1 Document Length: 44128 bytes Concurrency Level: 5 Time taken for tests: 45.82097 seconds Complete requests: 100 Failed requests: 21 (Connect: 0, Length: 21, Exceptions: 0) Write errors: 0 Total transferred: 4433142 bytes HTML transferred: 4412842 bytes Requests per second: 2.22 [#/sec] (mean) Time per request: 2254.105 [ms] (mean) Time per request: 450.821 [ms] (mean, across all concurrent requests) Transfer rate: 96.02 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 5 234 766.0 24 3016 Processing: 997 2002 1287.8 1330 6932 Waiting: 36 374 849.1 92 3082 Total: 1015 2237 1529.8 1393 7515 Percentage of the requests served within a certain time (ms) 50% 1393 66% 1756 75% 3162 80% 3670 90% 4298 95% 6101 98% 6948 99% 7515 100% 7515 (longest request) There are 21 failed requests which is surprising to me. The error type is Length. What does this mean? I don't see any explanation of the output of ab on the man page. When testing our development server I sometimes get this error from ab: Completed 1000 requests Completed 2000 requests Completed 3000 requests apr_recv: Connection reset by peer (104) Total of 3320 requests completed I don't know what this mean either. I am not sure why the ab would die of this kind of error instead of just reporting that an error happened. Hope you can explain this. Thanks Anders
