how often router or switch compute the cpu utilization?

[Ray Han]

Hi all,

we are using the command "sh proc cpu" to check the cpu utilization of router or switch as the above.

Cat4507R#sh proc c
CPU utilization for five seconds: 9%/0%; one minute: 11%; five minutes: 11%
PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
   1           0        11          0  0.00%  0.00%  0.00%   0 Chunk Manager   
   2         100    345801          0  0.00%  0.00%  0.00%   0 Load Meter      
   3           0         3          0  0.00%  0.00%  0.00%   0 SNMP Timers    

the above output shows 5sec util=9%, interrup cpu util=0%,

1min util=11%, 5min util=11%.

I wonder how often router/switch compute their cpu utilization.

1 sec? or 5 sec? or some other method?

as I think, if they collect it per every second it would be burden to the device.

but i can't exactly know about this.

is there anyone knows about this?

(interval to collect cpu utilization or another method if there exist)

[Mahesh Gohil]

Hello sanghee,

I think CPU is calculated as and when any process invoke. You can see uSecs of data
available per process.

However consolidated data for all process is available
for 5 sec, 1 min and 5 min
for 60 sec, 60 min, 72 hours (history command)

Regards

Mahesh

[Ray Han]

Thanks for your reply.

but i can't understand what you said.

"I think CPU is calculated as and when any process invoke. You can see uSecs of data
available per process."

=> does it means router/switch compute a cpu utilization using uSecs?

could you exlain this more detail?

[Mahesh Gohil]

Hello Sanghee,

PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process 

You can see above that cpu counts time it takes by process (displayed by PID-Process ID) for every uSecs. But consolidated data available is for

5sec,1min,5 min...can be displayed by "sh process cpu"

and for 60sec,60min, and 72 hours also...can be seen with "sh process cpu history" command

Meaning as and when a process ask for cpu cycle that is stored and available.

Hope this is clear now

Regards

Mahesh