CPU 100% P2P

How to solve this use of CPU high load on the when the P2P protocol is in use?

Note, I’m using Web proxy to filter the pages that my clients.

Any tips to solve this high-load processing problem with P2P applications?

I would not want to block P2P, but I believe that there is any way rule to fix this problem. I say this because I had the same problem-enabled Web Proxy, filtering the outside world, and solved the CPU high load proxy, using with this rule.
I ask, is there a way to solve this problem with P2P?

Sorry about my English.