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Benchmark

Introduction

There are many different tools available to measure the realtime performance of a system.

The cyclictest is the simplest and most usefull benchmark.

Tools

Cyclictest

Standard tool to measure the maximum jitter of a system.

Cyclictest

Influences on real-time behaviour

The following things can influence the real-time behaviour:

  • CPU
    • Mobile x86 CPU (with suffix like U, Y and M i.e i7-4600U) seems to performe much worse than non mobile processors. Mobile processer add about 100us-200us jitter.
    • ARM processer seem to have about 60us max jitter and a high medium jitter
  • Kernel version
    • 4.4.169-rt177 seems to be better than 4.19.15-rt12
  • BIOS settings
  • Some drivers, like WiFi driver, may negatively influence latency

Methodical procedure

Overview

At first, test the most basic system possible. With this test, you can get a baseline of the best possible real-time perfomance of the hardware. Every feature added will make the system more complex and add more stuff which can increase jitter.

With this aproach you can get a feeling which performance is possible and which part of the system is responsible for a high jitter.