testing and optimizing mysql based app for a shared server

[Kshitij Ahuja]

I am running a php app on a shared Linux server. A while ago my cpanel account was locked because the database had been consuming too muh CPU time, so it had to be shut to so other shared users don't suffer.

I identified the problematic SQL, fixed it and had the host look at it. They then confirmed it working within limits and reactivated my account.

My understanding is that the problem occurred because of simultaneous use by many users, that is, because of load. My question therefore is what methods, techniques, software etc do you recommend to test the app for use on a shared server so I know how it is going to behave under what load as well the maximum simultaneous users the app can tolerate.

Thanks.