CPU Usage exceeds

Dear Experts

We have a client on Solaris with Veritas Cluster Server 6.0.1

It is a 2 Node cluster

In logs it usually prints CPU usage exceed messages, at times it have cross 90%

I wanted to know how does it calculate the CPU usage, its obvious that server contains multiple CPU therefore the messages printed in the logs are combine of all the CPU or does it calculate individually ?

Regards