Intermittent High CPU Utilization

rshum · ‎06-11-2009

I'm running CatOS 6.3.3 on a Sup1. I get some seriously high CPU utilization intermittently. When I do a show proc cpu I get a THREAD process running abnormally high. Does anyone know what this is doing?

Here's a show proc I just did. Just the odd process because the entire output is too large for the body of the post.

CCF-c6509-1> (enable) sho proc cpu

CPU utilization for five seconds: 98.04%

one minute: 95.31%

five minutes: 75.40%

146 24301178 14437203 437000 71.42% 67.35% 45.41% -2 THREAD

tstanik · ‎06-17-2009

Common Causes and Solutions for High CPU Utilization Issues

1. IP Unreachables

When an access group denies a packet, the MSFC sends ICMP unreachable messages. This action occurs by default.

2. NAT Translations

NAT utilizes both hardware and software forwarding. The initial establishment of the NAT tranlsations must be done in software and further forwarding is done with hardware. NAT also utilizes the Netflow table (128 KB maximum).

3. Use of CEF FIB Table Space in the Flow Cache Table

4. Optimized ACL Logging.

5. Rate Limit of Packets to the CPU.