measure apache website performance
I have a apache website (static/ HTML) and I receive complain that it's being slow. top doesn't show heavy load, there are un-utilized RAM/ swap memory, ps -ef | grep httpd | wc -l shows 152 processes. access and error logs are of not much help - they show the usual HTTP/200 and HTTP/xxx but when I test the site either from inside or outside the network it's slow (16 seconds to open the home page).
Does anyone know what other methods I can use to see the issue with the website? I don't want to install any new module to measure performance.
Thanks for any help.