I've recently been helping out a forum which has been warned by their host for server load. The cpu usage of the forum rocketed seemingly randomly and stuck, with a single php file taking up a large amount of CPU time...
This is a heavily modified XMB forum. It is not the busiest board in the world, with a maximum of 20 users online at one time. XMB usually handles this kind of usage with ease, so I thought it was probably the modifications which had been applied to it. So I uploaded a clean version of the file which was causing the problem, and CPU usage by the file did not decrease. I'm kind of at a loss.. Could this have been a change to server settings by the host which caused this jump in CPU usage?
If this isn't solved by Monday, the host is kicking the forum out, so I'm trying numerous things to reduce the load. Any tips at all for this, possible routes I could take to reduce the CPU usage by this file would be greatly appreciated.
It isn't always the number of users, I've seen boards with a dozen users on at a time cause all sorts of problem, sloppy coding, poor add-on like ones that generate unique images for posts etc.. (think its something to do with winamp?' and corrupt (but not flagged as corrupt) database tables can all case problem.