Linux Command to Check CPU Utilization

Checking CPU utilization is essential for maintaining system performance and identifying system issues. In Linux, various commands such as top, mpstat, sar and iostat provide real-time insights into how your CPU is being used, helping you understand workload distribution and optimize resource management.

Whether you're troubleshooting system slowdowns or analyzing performance for heavy applications, these commands offer clear and actionable data.

This article covers the most effective Linux commands to check CPU utilization, ensuring you have the tools to keep your system running smoothly.

How to Check CPU Utilization in Linux with Command Line

Here are the following commands to check the CPU Utilization in Linux and their working to view and interpret CPU usage:

Check CPU Utilization by top command

The top command offers a dynamic, real-time view of running processes, displaying CPU and memory usage. By default, processes are listed in order of CPU consumption, allowing you to identify resource-intensive tasks easily. Pressing '1' within top displays CPU statistics for individual cores.

In your Linux terminal, write this top command:

top

This will display a real-time overview of system processes, CPU, and memory usage.

The upper section provides system summary information, including:

• Uptime: How long the system has been running.
• User Sessions: Number of active user sessions.
• Load Average: System load over the past 1, 5, and 15 minutes.
• Tasks: Total number of tasks and their states (running, sleeping, stopped, zombie).
• CPU Usage: Percentage breakdown of CPU usage across different modes (user, system, idle, etc.).
• Memory Usage: Information on total, used, free, and cached memory.

The lower section lists active processes with details such as:

• PID: Process ID.
• USER: Owner of the process.
• PR: Priority of the process.
• %CPU: CPU usage percentage.
• %MEM: Memory usage percentage.
• TIME+: Total CPU time consumed by the process.
• COMMAND: Command that initiated the process.

To hides all the idle processes in the system, and making it easier to sort through the list, use top -i:

top -i

To quit the top function, press q.

Some other useful commands while top is running include:

• M - sort task list by memory usage.
• P - sort task list by processor usage.
• N - sort task list by process ID.
• T - sort task list by run time.

Check CPU Utilization mpstat Command

The mpstat command in Linux provides detailed processor-related statistics, making it a valuable tool for monitoring CPU performance, especially in multi-processor systems.

Ensure the sysstat package, which includes mpstat, is installed:

sudo apt install sysstat

After installation, execute mpstat to display CPU usage statistics:

mpstat

To view statistics for a specific processor (e.g., CPU 0):

mpstat -P 0

To display statistics for all processors:

mpstat -P ALL

To capture multiple snapshots at defined intervals (e.g., every 5 seconds, 7 times):

mpstat 5 7

Understanding mpstat Output:

The output includes several columns, each representing a specific CPU metric:

• %usr: CPU time spent in user mode.
• %nice: CPU time for user processes with a positive nice value.
• %sys: CPU time spent in system (kernel) mode.
• %iowait: CPU time waiting for I/O operations to complete.
• %irq: CPU time handling hardware interrupts.
• %soft: CPU time handling software interrupts.
• %steal: CPU time involuntarily waiting while the hypervisor services another virtual processor.
• %guest: CPU time running virtual processors.
• %idle: CPU idle time.

Check CPU Utilization iostat Command

Theiostat command in Linux is a powerful utility for monitoring system input/output (I/O) statistics, providing insights into CPU utilization and disk I/O performance.

To display CPU and device I/O statistics:

iostat

To display statistics at regular intervals (e.g., every 2 seconds):

iostat 2

Check CPU Utilization sar Command

The sar (System Activity Reporter) command in Linux is a versatile tool for monitoring system performance, providing real-time and historical data on various system metrics.

To display CPU utilization:

sar -u 5

To display memory usage:

sar -r

To display network statistics:

sar -n DEV

Additional Commands to find CPU information in Linux

In Linux, several commands provide detailed information about your system's CPU. Here's an overview of some essential tools:

1. nproc Command:

The nproc command displays the number of processing units available. This is particularly useful when assessing system load or performance.

The nproc command displays the number of processing units available. This is particularly useful when assessing system load or performance.

Display Total Processing Units:

nproc --all

This command outputs the total number of processing units, calculated as:

Threads per core × Cores per socket × Sockets

Exclude Specific Processing Units:

nproc --ignore=N

Replace N with the number of processing units to exclude from the count.

2. dmidecode Command

The dmidecode command extracts hardware information from the system's Desktop Management Interface (DMI) or System Management BIOS (SMBIOS). It provides details about the BIOS, system, motherboard, chassis, cache, and CPU. Superuser privileges are required to execute this command.

Run dmidecode:

sudo dmidecode

Filter for Processor Information:

sudo dmidecode | grep -i processor

This command filters the output to display only lines containing the term "processor".

3. inxi Command

The inxi command provides comprehensive system information, including CPU details. It may not be installed by default but can be added from standard repositories.

Display Basic System Information:

inxi -b

This command provides an overview, including CPU make and model, speed, kernel version, uptime, memory, storage, running processes, shell, and the inxi version.

4. cpuid Command

The cpuid command retrieves detailed information about the x86 CPU, including vendor ID, version, features, and other specifications. It is not installed by default but can be installed from standard repositories.

Run cpuid:

cpuid

This command outputs extensive details about the CPU, providing a comprehensive understanding of the processor installed on your system.

These commands are invaluable for system administrators and users seeking to gather detailed CPU information on Linux systems. They assist in performance assessment, troubleshooting, and system optimization.