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CPU Usage on an 8-Core EC2 Instance: Interpretation and Performance Optimization

CPU Usage on an 8-Core EC2 Instance: Interpretation and Performance Optimization

This guide explains how to interpret CPU usage on an 8-core EC2 instance, including how to analyze multi-core utilization, monitor system performance, and optimize resource allocation. It covers key metrics, monitoring tools, and best practices to ensure efficient workload management on AWS EC2

Published Mar 12, 2025

Understanding CPU Usage on an 8-Core System

When analyzing CPU usage on a system with 8 CPU cores, it’s crucial to understand how the percentage of CPU usage is interpreted.
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Using Top command
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Using htop
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Single-Core Usage

  • 100% CPU usage: This means one core is fully utilized.
  • 800% CPU usage: This means all eight cores are fully utilized.

Multi-Core Usage

  • If a process is using 365.2% CPU, it means that the process is utilizing approximately 3.65 cores out of the available 8 cores.
  • This is calculated as:
    365.2% ÷ 100% per core = 3.652 cores.

Interpretation

  • 365.2% CPU Usage:
    • The RW process is utilizing about 3.65 cores.
    • On an 8-core system, this means RW is using approximately 45.65% of the total CPU capacity (3.65 cores out of 8).

Is This Acceptable?

To determine if this CPU usage is acceptable, consider the following:

Expected Behavior

  • Verify if the high CPU usage by RW is expected behavior and in this case it is expected behavior

System Performance

  • Monitor overall system performance to ensure that other processes are not being negatively impacted.
  • Use tools like:
    • top
    • htop
    • vmstat
      to get a real-time view of CPU usage and system load.

Load Average

  • Check the load average to see if the system is handling the load effectively.
    • Ideally, the load average should be below the number of CPU cores.
    • In your case, the load average values are: 5.27, 5.43, and 5.28, which are below 8, indicating that the system is managing the load but is under significant usage.

Resource Allocation

  • If necessary, adjust the resource allocation for RW or other processes to ensure balanced resource usage.
  • This can be done using tools like cgroups or other resource management tools.

Example Commands to Monitor System Performance

# Check the total number of CPU cores
lscpu | grep '^CPU(s):'
# Monitor system performance using top
top
# Monitor system performance using htop (if installed) to install yum install htop
htop
# Monitor system performance using vmstat
vmstat 1

This structure helps break down the information clearly, making it easier for readers to follow along and understand the details about CPU usage and system performance
 

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