[Zope] test performance statistics

Hi, I am testing a website running on zope(apache and one tesing instance on squid) I was able to generate a few graphs showing http responses vs time etc...i would like to have some more information on how I can analyse and/or use this information in understanding and fine tuning my server performance.Can some body help me or suggest any good sites for this. Thx --------------------------------- Do you Yahoo!? Yahoo! News - Today's headlines