AR1220E shows 2 CPU on display cpu-usage command

Publication Date:  2016-11-28 Views:  370 Downloads:  0
Issue Description

When running the display cpu-usage command, customer can see 2 CPU, 1 working and the other at 0% usage, they want to know why is this.

Handling Process

Customer is doing some test with AR1220E. They are stressing the device to the limit but when they checked CPU-Usage they realize it looks AR1220E has 2 CPU´s so they ask how to stress both CPU´s.

First we need to confirm if AR1220E has 2 CPU´s and if those CPU´s are for Data Plane and if yes, how the costumer can stress both CPU´s for the test.

This is what they got by display cpu-usage:


[AR1220E]dis cpu-usage

CPU   Usage Stat. Cycle: 10 (Second)

CPU   Usage Stat. Time : 2016-06-24  15:29:08

Control Plane

    CPU Usage:  7.7%   Max: 44.2%

    User:  3.0%   System:  3.3%   SoftIrq:  0.2%   HardIrq:  1.0%   Idle: 92.3% 

    CPU utilization for ten seconds:  7.7%  one minute:   7.0%  five minutes:   6.0% .

Data    Plane

    CPU Usage: 100%   Max: 100%

    CPU utilization for ten seconds: 100%  one minute:  66.8%  five minutes:  52.8% .


PID   ProcessName         CPU%     CoreIndex      Runtime     State

267   cap32ar1220e        100%      CPU1           331345030   R <---------------------------------------------

266   main_task           7.6%      CPU0           43073462    S

191   k3gdevd             0.0%      CPU0           2106        D

12    sync_supers         0.0%      CPU0           1480        S

265   cap32ar1220e        0.0%      CPU0           1239        S<---------------------------------------------

1     init                0.0%      CPU0           442         S

30    mtdblockd           0.0%      CPU0           57          S

130   loop0               0.0%      CPU0           34          S



AR1220E has 2 CPU, and one CPU (CPU 0) belongs to Control Planeanother CPU (CPU1) is for Data Plane.

         How to Test:

1.       Control Plane’ CPU (CPU 0):  To enable business functions as much as possible.

For example, search information by SNMP Manager (U2000/eSight), get big files from AR by FTP.

2.       Data Plane’ CPU (CPU 1):  push heavy traffic to  AR1220E  by  tester device.

                  Why the same task “cap32ar1220e ”   exists  on two CPU?

The “cap32ar1220e ” on Data Plane’ CPU (CPU 1) is Real and effective,

and  “cap32ar1220e ” on Control Plane’ CPU (CPU 0) is a mirror task, there is no real effect.