unusual high server load- how to trace down the faulty scripts?

[bluewmaster]

Hello people,
first of all I am sorry if this is a stupid question, but:
I have a dedicated server running CentOS, with a quite powerful hardware: dual 3 Ghz processor, 2 Gb Ram, and I`m running about 25-30 sites.
from a while the server has unusual high loads, and I keep getting mails from WHM that "the CPU has been maxed out in the past 6 hours".
we also had hacker attacks on the server, but it`s cleaned up.
my question is:
how can I trace down what processes are running on the server, because all I can see that mysql and httpd are causing the high loads, and in this case:
how can I trace down if there are any php scripts causing the high loads, maybe incorrect scripts, etc.
is there any tool for this?
thanks!

[likwid]

If httpd and mysqld are causing high loads, you can try setting them to a lower log level. Look for the same thing being done over and over. Also, if you're using perl or python on the sites, you want to run those in a debug mode also.

[bluewmaster]

Hi likwid,
thanks for your reaction.
I had perl running on the server, but I changed it`s ownership to root, and made it accessible only for root.
this cutted down the usage of perl.
the sites on the server don`t use it anyway, so this was useless.
python is not causing high load, so this one is ok.
the problem is mysql and httpd.
how do I set them to a lower log level? and where do I find all their logs?
thanks