[c-nsp] 7206vxr cpu usage.

[Justin Shore]

Keith wrote:
> Have a 7206vxr w/NPE-G1 and a couple of PA gig adapters, one with
> an SFP one with a GBIC.
> 
> We have a fiber connection that was 100Meg, plugged into GE0/1.
> 
> We added another fiber connection that is GigE and connected to the GBIC.
> This morning I cut over from the old 100meg fiber to the fiber in the
> GBIC. It was just a matter of moving the IP address of GE0/1 to GE1/0 and
> we were away and running.
> 
> Since then, the router CPU has gone up by about 10%. Normally at this time
> of day its about 22-23%, it is now about 32%. Normally at peak times the
> CPU barely broke 25%. I'm guessing but it looks like it might break 40% at
> peak times now.
> 
> Is the router working harder because of the GBIC and using gig ethernet
> rather than faste? We were using a gig port on the NPE at 100 meg.
> 
> sh proc cpu shows that IP input is the top process and ip cef is enabled.

So before you had data coming in Gi0/1.  Where was it going to?  My 
thought here is that the data is now coming in Gi1/0 on a PA which has 
to cross one of the PCI buses.  Were you to say that track used to come 
in Gi0/1 and exit Gi0/2 then I wouldn't expect the load to go up because 
of the PCI bus.  Of course if it's now coming in Gi1/0 on a PA, dropping 
onto the PCI bus and then exiting on onboard GigE int (or for that 
matter another PA) then I would expect the PCI bus to be loaded more and 
the load on the router to increase accordingly.  Maybe someone from 
Cisco.com could give us more insight.  I'm curious about this too 
because one day I may find myself in a similar situation.

Justin