So I've been trying to use apache ab to benchmark performance, but I'm having trouble understanding why I'm getting these results. FYI, its a PHP app using Zend Framework, mySQL database, and mostly default httpd.conf settings. If I set a simple test of 1 concurrent user and 10 requests, it seems like it takes just as long to run as 10 concurrent users and 10 requests, like it's basically just running one request at a time. I've used "top" to monitor the CPU and RAM usage, and with the concurrency level of 10, it hovers around 50%, and RAM there is no swapping going on and I still have about 400MB free. I also checked the httpd.conf file and max clients is the default 256.
-c 1 -n 10
Concurrency Level: 1
Time taken for tests: 11.594 seconds
Complete requests: 10
Failed requests: 0
Write errors: 0
Keep-Alive requests: 0
Total transferred: 738770 bytes
HTML transferred: 735680 bytes
Requests per second: 0.86 [#/sec] (mean)
Time per request: 1159.353 [ms] (mean)
Time per request: 1159.353 [ms] (mean, across all concurrent requests)
Transfer rate: 62.23 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.1 0 0
Processing: 1126 1159 21.7 1168 1190
Waiting: 1094 1128 22.7 1138 1160
Total: 1126 1159 21.7 1168 1190
Percentage of the requests served within a certain time (ms)
50% 1168
66% 1171
75% 1172
80% 1178
90% 1190
95% 1190
98% 1190
99% 1190
100% 1190 (longest request)
-c 10 -n 10
Concurrency Level: 10
Time taken for tests: 11.409 seconds
Complete requests: 10
Failed requests: 0
Write errors: 0
Keep-Alive requests: 0
Total transferred: 738770 bytes
HTML transferred: 735680 bytes
Requests per second: 0.88 [#/sec] (mean)
Time per request: 11408.835 [ms] (mean)
Time per request: 1140.883 [ms] (mean, across all concurrent requests)
Transfer rate: 63.24 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 2 18 9.8 16 30
Processing: 1429 6316 3330.1 6821 11399
Waiting: 1388 6270 3330.7 6761 11353
Total: 1445 6334 3331.7 6823 11408
Percentage of the requests served within a certain time (ms)
50% 6823
66% 7877
75% 9069
80% 10185
90% 11408
95% 11408
98% 11408
99% 11408
100% 11408 (longest request)