Initial performance results for leader/follower MPM

[Brian Pane <br...@cnet.com>]

I ran a quick performance comparison of the worker and
leader/follower MPMs.

Setup:
 - 2.0.36, with 64 threads per child process for both worker and leader
 - httpd and client both running on an 8-CPU Sun with Solaris 8
 - test case: use ab to load a 10KB or 0-byte file (non-mod_include)

I need to do further testing with a better benchmark setup (a client
driver with more concurrency, running on separate machines from the
server), but these initial results are promising:

      number of    requests/second
file    clients     size  (ab -c arg)   worker   leader
----  -----------   ------   ------
0         10         621      643
0         50         598      630
0        100         134      622
10KB      10         564      584
10KB      50         563      583
10KB     100         131      555

For the 10- and 50-connection tests, I think the difference
between worker and leader/follower is due mainly to the reduced
mutex contention in the latter.

--Brian