Cisco 7206 + NPE G1 - High CPU usage

[mmendis]

Dear All,

I have a Cisco 7206VXR + NPE G1 module , recently router causing high CPU usage even without high traffic. Appreciate if some one can help me on this ?

CPU utilization for five seconds: 68%/65%; one minute: 66%; five minutes: 66%
 PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
  41    75762496   5918035      12802  1.22%  1.22%  1.22%   0 Per-Second Jobs  
  34         584       232       2517  0.49%  0.29%  0.06%   2 SSH Process      
  60   2039043162116830346         96  0.49%  0.22%  0.22%   0 IP Input         
  37     5497404    968207       5677  0.16%  0.10%  0.11%   0 Net Background   
 185    11725616  13610810        861  0.16%  0.03%  0.09%   0 SNMP ENGINE      
   2       30212   1182298         25  0.08%  0.01%  0.00%   0 Load Meter       
  25     1533428  16764692         91  0.08%  0.01%  0.00%   0 ARP Input        
 112        6976     10875        641  0.08%  0.01%  0.00%   0 TPLUS            
  66       14312  23086305          0  0.08%  0.00%  0.00%   0 SSS Feature Time
 183     2052156  26537733         77  0.08%  0.01%  0.00%   0 IP SNMP          
 189      166220 181156542          0  0.08%  0.06%  0.08%   0 RADIUS           
  12           0         2          0  0.00%  0.00%  0.00%   0 AAA high-capacit
  13           0       284          0  0.00%  0.00%  0.00%   0 AAA_SERVER_DEADT
  11           0         2          0  0.00%  0.00%  0.00%   0 ATM VC Auto Crea

show int summary

 *: interface is up
 IHQ: pkts in input hold queue     IQD: pkts dropped from input queue
 OHQ: pkts in output hold queue    OQD: pkts dropped from output queue
 RXBS: rx rate (bits/sec)          RXPS: rx rate (pkts/sec)
 TXBS: tx rate (bits/sec)          TXPS: tx rate (pkts/sec)
 TRTL: throttle count

  Interface              IHQ   IQD  OHQ   OQD  RXBS RXPS  TXBS TXPS TRTL
------------------------------------------------------------------------
* GigabitEthernet0/1       0   106    0  9355 57787000  18566 240263000  32321    0
  GigabitEthernet0/2       0     0    0     0     0    0     0    0    0
  GigabitEthernet0/2.1     -     -    -     -     -    -     -    -   -
* GigabitEthernet0/3       0 217685    0     0 239586000  32030 58196000  18330    0

System image file is "disk2:c7200-pk9u2-mz.124-17a.bin"

[Mark Malone]

Hi

Large amount of interrupt traffic there that would definitely jam up cpu

CPU utilization for five seconds: 68%/65%; one minute: 66%; five minutes: 66%

http://www.cisco.com/c/en/us/support/docs/routers/7500-series-routers/41120-highcpu-interrupts.html

Have you checked cef if that's under stress and maxed out , if it is it can punt traffic to cpu adding to issues , some good general tshoot commands to take in the doc above specifically for these interrupt issues

There will always be interrupt traffic but Cisco recommend I think it was no more than 5% anytime

If you want to post some of the outputs from the doc I can check them with you

running the show tech through the output interpreter may give you some info as well

[Elliott Willink]

Hi mmendis,

The NPE-G1 is not a hardware/ASIC based routing platform, so generation of interrupts when routing traffic is totally normal - The closer to 100% you get, the closer you are to maxing out the routing throughput of the NPE-G1.

The numbers you are seeing are also normal. You are pushing about 300mbps of traffic, and generating 65% CPU is about normal for the NPE-G1 I would guestimate. You won't see more than about 500 - 600mbit out of a NPE-G1 (depending on services) so your CPU utilisation correlates.

This is nothing to worry about either - Your 7206 will happily route all day every day at 65% CPU :)

Hope this helps!

[mmendis]

Dear Elliot,

Thanks for the reply and sorry for the delayed in reply.

This router handled more than 400M traffic with the CPU below 40%. It suddenly occurred and i couldn't find the issue. But I think this is an issue due to CEF table problem. Please refer below.

show cef drop
CEF Drop Statistics
Slot  Encap_fail  Unresolved Unsupported    No_route      No_adj  ChkSum_Err
RP          6491           0           0       42063           0           0

[mmendis]

Thanks Mark,

And sorry for the delayed in reply... I think above issue is related to Cisco CEF ... Please refer following output. No Route stat is high and increasing. Any idea about following.

show cef drop
CEF Drop Statistics
Slot  Encap_fail  Unresolved Unsupported    No_route      No_adj  ChkSum_Err
RP          6491           0           0       42063           0           0