Real-time extensions for Linux are a set of kernel patches and configuration options that aim to improve the real-time responsiveness of the operating system. In a general-purpose operating system such as Linux, the kernel scheduler may not always give the highest priority to time-critical tasks, leading to unpredictable response times and reduced performance. Real-time extensions address this issue by providing mechanisms for prioritizing real-time tasks and reducing latency.
One popular real-time extension for Linux is the PREEMPT_RT patch, which modifies the kernel to allow for fully preemptive multitasking. This means that a running task can be interrupted at any time by a higher-priority task, ensuring that real-time tasks are executed with minimal latency. The PREEMPT_RT patch also includes support for real-time scheduling policies, such as the SCHED_FIFO and SCHED_RR policies, which allow real-time tasks to be scheduled with higher priority than regular tasks.
Other real-time extensions for Linux include the Xenomai and RTAI frameworks, which provide a range of real-time APIs and services for developing real-time applications. These frameworks can be used to develop applications with high determinism and low latency, such as industrial control systems, robotics, and multimedia processing.
Real-time extensions can be installed and configured on a Linux system through a combination of kernel patches, configuration options, and user-space libraries. However, it is important to note that real-time extensions may have a trade-off in terms of increased system complexity and reduced overall system throughput. Therefore, they should be used judiciously and only when necessary for specific real-time applications.