[c-nsp] 3750 with high CPU

[Rubens Kuhl Jr.]

I'm trying to diagnose what is causing a 3750 ME to have high cpu
usage. "show proc cpu sorted" shows no process with more than 3% CPU
usage; sometimes the most consuming process is "IP SNMP", sometimes
it's "MFI LD Timer", sometimes it is "Spanning Tree", but adding up
the % doesn't come even close to the total amount:
"CPU utilization for five seconds: 64%/56%; one minute: 64%; five minutes: 63%"

So, it seems something in the interrupt path is causing the CPU usage.

#sh ip cef switching statistics

       Reason                          Drop       Punt  Punt2Host
RP RIB Packet destined for us             0   10221271          0
RP RIB Total                              0   10221271          0

RP LES No route                       13826          0        555
RP LES Packet destined for us             0    1041551          0
RP LES No adjacency                   18970          0     171714
RP LES Unresolved route                  45          0          0
RP LES TTL expired                        0          0       8440
RP LES IP options set                     0          0      11111
RP LES Routed to Null0                12735          0      15991
RP LES IP redirects                       0          0         56
RP LES Unclassified reason             3648          0          0
RP LES Total                          49224    1041551     207867

All    Total                          49224   11262822     207867


RP RIB punts are ocurring at a rate of 5 pps, and RP LES punts have a
near 1 pps rate. Are these rates enough to take the 3750 CPU to 60%
usage ? Any ideas of what to look for ?

IOS version is 12.2(25)SED, running MPLS, IBGP for VPNv4 and OSPF.



Rubens