I've had an issue since upgrading my distro a couple of weeks ago from hardy; receiving data after making a request has increasing intervals of nothing, as you can see from the picture below.
I have since reinstalled fresh from an Ubuntu 10.04 Server (i386) disk, but am still having the same issues. I'm running on a LigHTTPd, MySQL, PHP5 stack. The surprising thing is, that local browsing using lynx is super fast, as expected. Initially, after reinstalling, I copied over the old configuration files from the previous installation, but have since reinstalled LigHTTPd and rebuilt the config file from scratch. The only correlation I could find, was that I attempted installation of ionCube and Zend Optimizer for a script I was testing, however I would think that it could no longer impact seeing I had reinstalled the OS. I have also removed Suhosin just in case, however it had no impact.
I'm thinking it possibly has something to do with networking, but I wouldn't know where to start. The server is manually assigned an IP by it's MAC address on the router.
The fact that the time seems to be exponential (to a point) worries me. I've tried strace'ing the LigHTTPd and MySQL processes, however I couldn't see anything obvious, not that I'd really know what I'm looking for. RAM and CPU usage don't seem to be out of the ordinary, but I can't say its perfect..
I'm hoping someone has experienced the same, or can point me in a direction, as searching has proved fruitless as I don't know anything specific. Config files can be posted, if requested.