Hi, My 1760 router do have VPN hardware module, without it, CPU was high and encryption process too much of the CPU, now after we install VPN module, there is no cpu % for encryption process, but my question is sum of the CPU % is much much lower than the total CPU %, what are the hidden processes taking all these CPU
HHRTR01#sh proc cpu | ex 0.00
CPU utilization for five seconds: 15%/11%; one minute: 16%; five minutes: 18%
PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
5 145439 9297 15643 1.06% 0.22% 0.18% 0 Check heaps
50 2312 473 4887 2.12% 0.56% 0.25% 6 SSH Process
51 69168 50055 1381 0.24% 0.18% 0.19% 0 IP Input
0.16%+0.57% = 0.73%
0.73% rounded = 1%
Total CPU utilization = 35%
CPU utilization under interrupt = 34%
CPU utilization in processes = 35%-34% = 1% = 0.73% rounded
You can't see what's happening under interrupt ('show stacks' gives you the amount of network/timer/... interrupts but it's not very useful).
Usually, what happens under interrupt is the traffic forwarding using CEF.
So, at first sight, there's nothing to worry about on your router. It's a bit busy forwarding packets.
If you need to troubleshoot the CPU utilization under interrupt, you will need to do profiling with the assistance of a TAC engineer who has the ability to decode the profiling results.
hope this helps,