CPU Performance Test in Linux: A Complete Benchmarking Guide

Introduction / Why This Is Needed

CPU performance testing in Linux allows you to objectively evaluate computation speed, stability under load, and compare results with reference values. This is critically important when selecting hardware for a server, tuning a system for high-load tasks (virtualization, compilation, rendering), or verifying performance after overclocking. As a result, you will obtain numerical metrics that will help you make an informed decision.

Requirements / Preparation

Before you begin, ensure that:

1. You have terminal access with sudo privileges (for installing packages).
2. Your system is updated: sudo apt update && sudo apt upgrade -y (for Debian/Ubuntu) or sudo dnf upgrade -y (for Fedora/CentOS).
3. You are working on a physical machine (results on a virtual machine may be distorted).
4. All non-critical applications are closed, and the system is running in Performance mode (you can check with the command cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor — it should output performance).

Step-by-Step Instructions

Step 1: Install Necessary Tools

Install the core utilities. For Debian/Ubuntu:

sudo apt install sysbench stress-ng

For Fedora/CentOS/RHEL:

sudo dnf install sysbench stress-ng

💡 Tip: Geekbench 6 is a proprietary tool. Download it from the official website, unpack it, and grant execute permissions: chmod +x geekbench6.

Step 2: Check CPU Configuration

Identify your processor's architecture:

lscpu

Pay attention to these lines:

• CPU(s): — total number of logical cores.
• Thread(s) per core: — threads per core (usually 1 or 2). You will need this data to correctly configure stress-ng.

Step 3: Run a CPU Test with sysbench

sysbench will perform a test using simple mathematical operations (prime number calculation). Run:

sysbench cpu --cpu-max-prime=20000 run

What this command does: calculates all prime numbers up to 20000 across all available cores. The result is the total execution time in seconds. Lower time means higher performance.

Step 4: Run a Stress Test with stress-ng

stress-ng creates intensive load, checking stability and heat output. To fully load all cores for 60 seconds:

stress-ng --cpu $(nproc) --timeout 60s

Important: this test can significantly increase CPU temperature. Monitor it (for example, with the command watch -n 1 sensors). If the temperature approaches the TjMax (usually 90-100°C), stop the test (Ctrl+C).

Step 5: Run the Comprehensive Geekbench Benchmark

Geekbench 6 evaluates both single-core and multi-core performance using real-world scenarios (compression, navigation, machine learning). Run:

./geekbench6

The results will be printed to the terminal and uploaded to the Geekbench server (if internet is available). You will receive two scores: Single-Core Score and Multi-Core Score. Save the link to the detailed report.

Step 6: Compare and Record Results

For convenience, save the output to files:

sysbench cpu --cpu-max-prime=20000 run > ~/cpu_benchmarks/sysbench.txt
stress-ng --cpu $(nproc) --timeout 60s 2>&1 | tee ~/cpu_benchmarks/stressng.log
./geekbench6 > ~/cpu_benchmarks/geekbench.txt

Create the ~/cpu_benchmarks directory if it doesn't exist. Now you have all the data needed to compare with other systems or after changes (such as overclocking).

Verifying the Results

A successful benchmark will complete without access errors and output numerical results. For sysbench, look for the total time: line. For stress-ng, the log will show the number of operations completed and the time. For Geekbench, look for the final scores. If the system did not crash during the stress test, the CPU is stable.

Potential Issues

• stress-ng: error: cpu stressor failed error: insufficient permissions or incompatible version. Ensure you are running with sudo and that your stress-ng version is up-to-date.
• System freezes or overheats: reduce the test duration (--timeout 30s) or the number of cores (instead of $(nproc), specify something like 4). Improve cooling.
• Geekbench fails to launch: check if dependencies are installed (libc6, libstdc++6). On Ubuntu/Debian: sudo apt install libc6 libstdc++6.
• Results vary significantly between runs: ensure there is a cooldown period between tests (5-10 minutes) and that the system is not performing background tasks (use top to check).

Additional Tips

• To test single-core performance with stress-ng, specify --cpu 1.
• To check the impact of the storage drive on overall performance, add the sysbench fileio test.
• Regularly compare your results with stock (default) settings to evaluate the effect of overclocking or system changes.