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Elastic Compute Service

High instance load issue

Troubleshooting and solution for high CPU usage or load of ECS instance with Linux system

Troubleshooting and solution for high CPU usage or load of ECS instance with Linux system

This topic describes how to use the Atop tool to troubleshoot high CPU usage or CPU load on a Linux instance.

Procedure

Log in to the target instance. For operation details, refer to Logging in to Linux instances.

Make sure that the Atop tool is installed on the target instance. If the Atop tool is not installed, execute the following commands to complete the installation.

CentOS

yum -y install atop

Ubuntu, Debian

apt -y install atop

Use the Atop tool to identify processes affecting CPU usage or CPU load.

Execute the following command in the target instance to view the real-time CPU usage ranking.

atop

Sample output

View historical system usage.

Execute the following command to view the system usage at the target time point.

tip

In this example, the time point of March 5, 2024, is used as the time when the problem occurred. Replace it with the actual time point.

Make sure that the specified abnormal time point is after you installed the Atop tool.

atop -r /var/log/atop/atop_20240305

Press t key to adjust and view later times. Press shift + t key to adjust and view earlier times.

View the CPU usage at the abnormal time point.

Identify the PID of the process that may cause issues based on real-time and historical usage.

Based on your current business, confirm whether the running status of the process that caused issues meets expectations.

If the process meets expectations

Optimize the program processing logic for this process to reduce CPU usage. You can also upgrade your instance configuration to prevent program operations from being affected due to low instance specifications. For details, see Changing instance types.

If the process fails to meet expectations

You can execute the following commands to manually terminate the abnormal process.

warning

Terminating the process may cause data loss of the target process.

Terminating key operating system processes may cause the system to restart. Please proceed with caution.

On the Atop monitoring page, press the k key to enter process termination mode.

Enter the target process PID, and press the Enter key to confirm.

Press the 9 key and press Enter to confirm and forcibly close the process.

Last updated: 2026.06.18 17:49:51