Linux top greater than 100 percent - CPU

14 October,2013 by Jack Vamvas

Question: I was using the Linux top command to monitor the CPU activity on a Linux server hosting.  To my surprise , I saw the CPU at 202% - what?! How can this be?

  

top - 16:45:37 up 127 days,  7:27,  1 user,  load average: 2.21, 2.23, 2.23
Tasks: 153 total,   1 running, 152 sleeping,   0 stopped,   0 zombie
Cpu(s): 24.6% us,  1.1% sy,  0.0% ni, 73.4% id,  1.0% wa,  0.0% hi,  0.0% si
Mem:  24684584k total, 16883612k used,  7800972k free,   608548k buffers
Swap: 12586936k total,    78384k used, 12508552k free, 14552460k cached

  PID USER      PR  NI %CPU    TIME+  %MEM  VIRT  RES  SHR S COMMAND
10257 db2inst1    25   0  202  16895:27 39.6 14.2g 9.3g 9.3g S db2sysc

 

Answer: It is  a useful command , but the high number is supposed to be the aggregate of all the cores.

The Linux top command  offers a continuous, real time look at the CPU activity.

To see a detailed core  breakdown , you’ll need to  type “1” after you’ve executed the command “top” . 

For example , you may see 202% , but once you’ve typed “1” , you may see 8 cores – with various usage levels at below 100% or lower

 

top - 13:36:43 up 129 days,  4:19,  1 user,  load average: 2.13, 2.16, 2.20
Tasks: 155 total,   1 running, 154 sleeping,   0 stopped,   0 zombie
Cpu0  :  0.3% us,  0.3% sy,  0.0% ni, 99.3% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu1  :  0.0% us,  0.3% sy,  0.0% ni, 99.7% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu2  :  0.0% us,  0.0% sy,  0.0% ni, 99.0% id,  1.0% wa,  0.0% hi,  0.0% si
Cpu3  :  9.0% us,  0.7% sy,  0.0% ni, 90.0% id,  0.3% wa,  0.0% hi,  0.0% si
Cpu4  :  0.0% us,  0.0% sy,  0.0% ni, 100.0% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu5  :  0.3% us,  0.0% sy,  0.0% ni, 99.7% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu6  : 96.3% us,  3.7% sy,  0.0% ni,  0.0% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu7  : 96.0% us,  3.0% sy,  0.0% ni,  1.0% id,  0.0% wa,  0.0% hi,  0.0% si
Mem:  24684584k total, 15487164k used,  9197420k free,   648812k buffers
Swap: 12586936k total,    78704k used, 12508232k free, 12221548k cached

  PID USER      PR  NI %CPU    TIME+  %MEM  VIRT  RES  SHR S COMMAND
10257 db2inst1    25   0  209  21499:35 40.2 14.2g 9.5g 9.4g S db2sysc

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Author: Jack Vamvas(http://www.dba-db2.com)

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