Linux is increasingly being used in systems where real-time performance is required. Examples include multimedia applications and robot, industrial, and automotive controllers.
Real-time systems are characterized by deadlines. When a missed deadline results in inconvenience or a diminished customer experience, we refer to this as soft real time. In contrast, hard real-time systems are considered failed when a deadline is missed.
Kernel preemption was the first significant feature in the Linux kernel that addressed system-wide latency.
Recent Linux kernels support several preemption modes, ranging from no preemption to full real-time preemption.
The real-time patch adds several key features to the Linux kernel, resulting in reliable low latencies.
The real-time patch includes several important measurement tools to aid in debugging and characterizing a real-time Linux implementation.
17.5.1. Suggestions for Additional Reading
Linux Kernel Development, 2nd Edition Robert Love Novell Press, 2005
