If the CPU is constantly loaded at 90–100% in Linux, it reduces performance and can cause overheating. Often, the culprits are hung processes, updates, or software conflicts.
Below are ways to diagnose and fix the issue.
Method 1: Checking Processes
- Run the command:
top
- Identify processes with high CPU usage
- If necessary, terminate the problematic process:
sudo kill -9 <PID>
Method 2: Checking Background Tasks and Updates
- Ensure there are no long-running updates or package builds
- For Debian/Ubuntu:
sudo apt update && sudo apt upgrade
Method 3: Clearing System Caches and Logs
- Logs and caches can consume resources:
sudo journalctl --vacuum-size=100M
sudo sync; echo 3 | sudo tee /proc/sys/vm/drop_caches
Method 4: Analyzing CPU Usage by Cores
mpstat -P ALL 1 5
- Identify which cores are overloaded
- If necessary, limit resource-intensive processes with
cpulimit
Conclusion
High CPU load is usually associated with hung processes or background tasks. Monitoring, terminating problematic processes, and clearing caches often resolve the issue.