CentOS
2.6.24-22-xen

$ ab -n 1000 -c 100 http://192.168.1.50/
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.1.50 (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
Finished 1000 requests

Server Software: Apache/2.2.3
Server Hostname: 192.168.1.50
Server Port: 80

Document Path: /
Document Length: 5043 bytes

Concurrency Level: 100
Time taken for tests: 2.92797 seconds
Complete requests: 1000
Failed requests: 0
Write errors: 0
Non-2xx responses: 1000
Total transferred: 5240000 bytes
HTML transferred: 5043000 bytes
Requests per second: 477.83 [#/sec] (mean)
Time per request: 209.280 [ms] (mean)
Time per request: 2.093 [ms] (mean, across all concurrent requests)
Transfer rate: 2445.05 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.4 0 7
Processing: 1 2 11.4 1 208
Waiting: 0 1 11.3 1 207
Total: 1 2 11.4 1 208

Percentage of the requests served within a certain time (ms)
50% 1
66% 2
75% 2
80% 2
90% 2
95% 2
98% 3
99% 4
100% 208 (longest request)

Ubuntu
2.6.24-22-xen

$ ab -n 1000 -c 100 http://192.168.1.51/
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 2006 The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.1.51 (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
Finished 1000 requests

Server Software: Apache/2.2.8
Server Hostname: 192.168.1.51
Server Port: 80

Document Path: /
Document Length: 5043 bytes

Concurrency Level: 100
Time taken for tests: 0.750044 seconds
Complete requests: 1000
Failed requests: 0
Write errors: 0
Total transferred: 5297000 bytes
HTML transferred: 5043000 bytes
Requests per second: 1333.26 [#/sec] (mean)
Time per request: 75.004 [ms] (mean)
Time per request: 0.750 [ms] (mean, across all concurrent requests)
Transfer rate: 6895.60 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 7 5.6 7 30
Processing: 2 40 104.1 12 694
Waiting: 1 39 104.1 11 693
Total: 2 47 104.2 21 706

Percentage of the requests served within a certain time (ms)
50% 21
66% 25
75% 29
80% 32
90% 45
95% 257
98% 285
99% 698
100% 706 (longest request)

Requests per second:
CentOS

731.19 [#/sec]
740.07 [#/sec]
810.05 [#/sec]
852.98 [#/sec]
746.45 [#/sec]

Ubuntu

1018.12 [#/sec]
1355.45 [#/sec]
1169.16 [#/sec]
1391.87 [#/sec]
1371.14 [#/sec]