Hi all, Thank you for all your suggestions. Now the load average on my server is back to normal again :) It is around 0.2 - 0.5 now with the same pageviews. Ok not just normal, actually the load average is even lower than when I was using CGI (which was around 0.6 - 1.2).
The changes I made: reduced MaxClients value from 300 to 150 in httpd.conf, preloaded CGI module by putting it inside startup.pl, unloaded some DSO modules that I didn't use. This article really helps me a lot: http://perl.apache.org/docs/1.0/guide/performance.html --bk