On 8-core server, 0-3 are configured as isolcpus and remaining cores (4-7) are available for system and user processes to run. My application has multiple processes which will run on any one of the mentioned non-isolcpu cores (4-7).

I need to find the total CPU utilization of the application (all processes combined) to determine the right isolcpus range to be configured for the system.

I'm quite confused about this way of calculating CPU utilization for a process or group of processes. Can somebody enlighten me in laymen terms? Thanks!

Went through related questions as well, none of them helped: https://serverfault.com/questions/648704/how-are-cpu-time-and-cpu-usage-the-same

  • does "process group" mean cgroup? Because in that case, there'd be tools for it. Commented Jan 12, 2022 at 17:58
  • No, I meant group of processes created by application itself to perform various actions (like file reading, computing, file writing).
    – surya
    Commented Jan 12, 2022 at 18:03

1 Answer 1


You can try the top command. First identify which process ID’s you wish to monitor, for example, you can run the ps -U <username> to see all processes currently running. Then you can use the top -p N1,N1,…, where N1 is the process ID of the first process you want to track. The output of top will tell you how much of the CPU’s resources each process is using, which in turn can tell you how much system resources the application is using. If you need more information such as individual threads or processes running under root or other users see the top man page (this one is quite extensive) and the ps man page.

  • Thanks, will top cmd includes isolcpu cpus as well for calculating cpu utilization?
    – surya
    Commented Jan 12, 2022 at 18:05
  • Yes, top will monitor all cpus in the system. The key 1 let’s you see information about different cores at the same time. Commented Jan 12, 2022 at 18:23

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