Slide 1

Real Time: A Definition

The Path to Real Time in Linux

Linux Priorities

Changing Real Time Priorities

Thread Level Priorities

Sched Policy

Sched Param

Inherit Sched

Priority Inversion

Priority Inheritance

PI-Futex

How fork() seems to work

How fork() really works

What happens during write?

Locking Memory

Stack Pre-Faulting

Timer frequency

The Effect of Timer Frequency

The Effect of Timer Frequency cont.

High-Res Timers

Sources Of Latency

The Linux O(1) Scheduler

Choosing and Expiring Tasks

Kernel Preemption Options

Soft Real Time

Hard and “Ruby” Hard Real Time

Nano Kernel Approach

Nano Kernel Approach

PREEMPT_RT

Vanilla Linux Contexts

PREEMPT_RT Linux Contexts

Interface Changes

Linux RT Benchmarking

Interrupt Response Times

Any Questions?