Some time ago, I used mod_fcgid on my server. Everything went fine, except when dotclear2 became needed. After some test, I concluded that it wont work with mod_fcgid given because of certain rewrite rules. This seems to be a known issue, and the only solution at the time of writing it to use mod_fastcgi in its stead. Difference between mod_fastcgi and mod_fcgid is mostly at license level. Although mod_fastcgi is somewhat non-free, and after some troubles with the configuration, I decided to give it a try ;-)[1]

After configuring two vhosts, one with mod_fcgid and one with mod_fastcgi, I benchmarked a simple "Hello world" program on Apache2. Results are speaking by themselves:

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

Document Path:          /
Document Length:        11 bytes

Concurrency Level:      5
Time taken for tests:   48.867314 seconds
Complete requests:      10000
Failed requests:        13
  (Connect: 0, Length: 13, Exceptions: 0)
Write errors:           0
Non-2xx responses:      13
Total transferred:      2959503 bytes
HTML transferred:       119256 bytes
Requests per second:    204.64 [#/sec] (mean)
Time per request:       24.434 [ms] (mean)
Time per request:       4.887 [ms] (mean, across all concurrent requests)
Transfer rate:          59.14 [Kbytes/sec] received

Connection Times (ms)
             min  mean[+/-sd] median   max
Connect:        0    0   0.0      0       0
Processing:     1   23 360.7      1   12064
Waiting:        1   23 360.7      1   12064
Total:          1   23 360.7      1   12064

Percentage of the requests served within a certain time (ms)
 50%      1
 66%      1
 75%      1
 80%      1
 90%      1
 95%      1
 98%     17
 99%     21
 100%  12064 (longest request)

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

Document Path:          /
Document Length:        11 bytes

Concurrency Level:      5
Time taken for tests:   18.150717 seconds
Complete requests:      10000
Failed requests:        0
Write errors:           0
Total transferred:      2950000 bytes
HTML transferred:       110000 bytes
Requests per second:    550.94 [#/sec] (mean)
Time per request:       9.075 [ms] (mean)
Time per request:       1.815 [ms] (mean, across all concurrent requests)
Transfer rate:          158.67 [Kbytes/sec] received

Connection Times (ms)
             min  mean[+/-sd] median   max
Connect:        0    0   0.0      0       0
Processing:     1    8 194.4      2   11504
Waiting:        1    8 194.4      2   11504
Total:          1    8 194.4      2   11504

Percentage of the requests served within a certain time (ms)
 50%      2
 66%      3
 75%      3
 80%      3
 90%      4
 95%     12
 98%     17
 99%     20
 100%  11504 (longest request)

I do not know if I'm doing wrong with mod_fcgid, but the fact is that mod_fastcgi operates at 250 request/second faster. No need to say, dotclear2 is coming soon on this blog :-)

[1] thank's Pep :-)