20 Years Later, Real-Time Linux Makes It To the Kernel

After 20 years of development, Real-Time Linux (PREEMPT_RT) has finally been integrated into the Linux mainline kernel, enabling its use in mission-critical devices and industrial hardware. An RTOS ensures deterministic behavior and time-critical task handling within strict deadlines. Despite its significance, the integration faced challenges due to technical complexity, politics, and funding. The Linux Foundation's Real-Time Linux collaborative project played a crucial role in coordinating efforts. Reworking the kernel's print_k function, a debugging tool with a hard delay, was the final hurdle. After extensive discussions and a compromise, print_k was modified to address concerns without compromising real-time performance. The integration of PREEMPT_RT marks a significant milestone, expanding the capabilities of Linux and opening up new possibilities for its use in critical applications.