ab - Apache HTTP server benchmarking tool is a linux shell software useful to perform a performance benchmark of a webpage of a website.

sudo apt-get install apache2-utils

The following command says that the ab command will execute 1000 times 10 concurrent access to the webpage with address http://wiki.altervista.org/cs/ab (this webpage). Results will be stored in the file test.dat.

ab -n 1000 -c 10 -g test.dat "http://wiki.altervista.org/cs/ab"

the output of this command is:

This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking wiki.altervista.org (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:        Apache
Server Hostname:        wiki.altervista.org
Server Port:            80

Document Path:          /cs/ab
Document Length:        8951 bytes

Concurrency Level:      10
Time taken for tests:   18.740 seconds
Complete requests:      1000
Failed requests:        0
Write errors:           0
Total transferred:      9430688 bytes
HTML transferred:       8958746 bytes
Requests per second:    53.36 [#/sec] (mean)
Time per request:       187.403 [ms] (mean)
Time per request:       18.740 [ms] (mean, across all concurrent requests)
Transfer rate:          491.44 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:       20   25   7.0     23      82
Processing:    71  162  80.9    140     398
Waiting:       50  135  78.5    111     372
Total:         92  187  81.7    164     421

Percentage of the requests served within a certain time (ms)
  50%    164
  66%    220
  75%    251
  80%    267
  90%    304
  95%    334
  98%    372
  99%    402
 100%    421 (longest request)