CODEWITHSUNDEEP
linuxperformanceamazon-web-servicesamazon-ec2server
Tiancheng Xu
Tiancheng Xu

Reputation: 49

Weird EC2 CPU usage

I'm really confused. Why does the load average and %CPU does not match the process CPU usage below. It seems like the process is eating up a lot of CPU while the AWS EC2 meters only says 25% CPU is used. click here to see image

Upvotes: 0

Views: 1118

Answers (3)

Join Free
Join Free

Reputation: 89

after you run command "top" you can press "1" on your keyboard to see individual CPU utilization, more details when you run command "man top" Note process "msqld" can use CPU from several resources and its utilization % could easily go beyond 100% in "top" display.

Upvotes: 1

McGrady
McGrady

Reputation: 11487

%CPU -- CPU Usage : The percentage of your CPU that is being used by the process. By default, top displays this as a percentage of a single CPU. On multi-core systems, you can have percentages that are greater than 100%. For example, if 3 cores are at 60% use, top will show a CPU use of 180%. You can toggle this behavior by hitting Shift+i while top is running to show the overall percentage of available CPUs in use.

load average: 22.56, 24.99, 26.51

From left to right, these numbers show you the average load over the last 1 minute, the last 5 minutes, and the last 15 minutes. 

us  --  User CPU time
  The time the CPU has spent running users' processes that are not niced.
sy  --  System CPU time
  The time the CPU has spent running the kernel and its processes.
ni  --  Nice CPU time
  The time the CPU has spent running users' proccess that have been niced.
wa  --  iowait
  Amount of time the CPU has been waiting for I/O to complete.
hi  --  Hardware IRQ
  The amount of time the CPU has been servicing hardware interrupts.
si  --  Software Interrupts
  The amount of time the CPU has been servicing software interrupts.
st  --  Steal Time
  The amount of CPU 'stolen' from this virtual machine by the hypervisor for other tasks (such as running another virtual machine).

See more details from In Linux “top” command what are us, sy, ni, id, wa, hi, si and st (for CPU usage).

Upvotes: 2

Jogendra Kumar
Jogendra Kumar

Reputation: 513

Hi maybe your app using single core and other cores are free. I think your instance has 4 CPU core and one is utilizing 100%. can you please check utilization by each core.

Upvotes: 0

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