How do I find out what's causing increased CPU usage on my Linode?
What's the best way to find out what programs or services are using the most CPU time and resources?
I recommend using the 'top' command to find out what's using the most CPU time on your Linode. We have a guide on the 'top' command here:
From there, checking the log files for the service may help narrow down the exact cause. Most services have log files in the /var/log directory. If the service is Apache, PHP, or MySQL the increase in CPU usage may be from an increase in website traffic.
don't forget using pidstat and other tools too
some useful links