Tracking the high CPU Usage question

[Makcik]

Hi guys,

For the last several weeks our IPS-powered Linode instance generates occasionally the following message:

Your Linode has exceeded the notification threshold (90) for CPU Usage by averaging 92.5% for the last 2 hours. 

Could you please provide hints how to track the real reason of such a CPU Usage spike? Update to the latest version (currently v4.5.4.2) doesn't seem to have resolved the issue.

Thanks in advance!