orz.2ch.io の鯖で worker + mod_perl2 + threaded perl で動かしてみた。
簡単なHello, worldスクリプトで試した結果。
apache1.3 + mod_perl より速いんでないかしら。

Concurrency Level: 100
Time taken for tests: 2.866818 seconds
Complete requests: 1000
Failed requests: 0
Write errors: 0
Total transferred: 131000 bytes
HTML transferred: 14000 bytes
Requests per second: 348.82 [#/sec] (mean)
Time per request: 286.682 [ms] (mean)
Time per request: 2.867 [ms] (mean, across all concurrent requests)
Transfer rate: 44.30 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 7 15.9 0 126
Processing: 34 269 503.6 92 1893
Waiting: 0 134 355.9 58 1776
Total: 34 277 510.0 92 1924

Percentage of the requests served within a certain time (ms)
50% 92
66% 111
75% 127
80% 140
90% 952
95% 1897
98% 1901
99% 1902
100% 1924 (longest request)

どうせproxyだから実行速度速くなくてもいいんだけどね。。。
ちなみに、prefork + cgi は遅すぎて話しになってなかったです。