Which Linux command will help you find the process that is consuming most of the CPU cycles?

There are situations where you often have to deal with application sluggishness or unresponsive application due to high CPU usage in Linux.

This happens when your Linux system CPU is too busy, usually it is not available to process other requests and the pending requests have to remain in the queue and wait until the CPU is free.

If you want to check which processes are hamming the CPU, you must use the appropriate commands to know the overall consumption processes of the CPU.

I believe there are only two primary commands that can identify and determine if your CPU is under stress, such as top command and ps command. Both of these commands are widely used by Linux administrators to troubleshoot high CPU Usage on Linux.

I’d like to go with the top command for most reasons instead of ps, but both will produce effective results, so you can choose the one you like.

We have already described in our previous article how to find high memory consumption processes in Linux.

1) top command to determine high CPU usage in Linux

The Linux top command is the best and most well known command that everyone uses to monitor Linux system performance.

The top command provides a dynamic real-time view of the running process on a Linux system.

It display system summary information, the list of processes currently being managed by the Linux kernel.

It displays various system information such as CPU usage, Memory usage, Swap Memory, Number of running processes, system uptime, system load, Buffer Size, Cache Size, Process PID, etc.

By default, it sorts the top output with the CPU usage and updates the top command data every 5 seconds.

If you want to see a clear view of the top command output for further analysis, this is a best way to run the top command in the batch mode.

Also, you need to understand the top command output to fix the performance problem on the system.

Details of the above command:

• top : This is a command.
• -b : Batch mode.
• head -50: Display first 50 lines in the output.
• PID : Unique ID of the process.
• USER : Owner of the process.
• PR : priority of the process.
• NI : The NICE value of the process.
• VIRT : How much virtual memory used by the process.
• RES : How much physical memory used by the process.
• SHR : How much shared memory used by the process.
• S : This indicates the status of the process: S=sleep R=running Z=zombie.
• %CPU : The percentage of CPU used by the process.
• %MEM : The percentage of RAM used by the process.
• TIME+ : How long the process being running.
• COMMAND : Name of the process.

If you want to see the full path of the command instead of the command name, run the following top command format.

2) ps command to check high CPU usage in Linux

ps stands for processes status, it display the information about the active/running processes on the system.

It provides a snapshot of the current processes along with detailed information like username, user id, cpu usage, memory usage, process start date and time command name etc.

Details of the above command:

• ps : This is a command.
• -e : Select all processes.
• -o : To customize a output format.
• –sort=-%cpu : Sort the ouput based on CPU usage.
• head : To display first 10 lines of the output
• PID : Unique ID of the process.
• PPID : Unique ID of the parent process.
• %MEM : The percentage of RAM used by the process.
• %CPU : The percentage of CPU used by the process.
• Command : Name of the process.

If you only want to see the command name instead of the absolute path of the command, use the ps command format below.

Final Thoughts

In this guide, we’ve shown you how to identify and determine high CPU usage process using top command and ps command in Linux.

If you have any questions or feedback, feel free to comment below.