PREEMPT RT

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PREEMPT_RT was a set of out-of-tree patches for the Linux kernel which implement both hard and soft real-time computing capabilities. [1]

Contents

On September 20, 2024, PREEMPT_RT was fully merged and enabled in mainline Linux on the supported architectures x86, x86_64, RISC-V and ARM64. [2] This made kernel v6.12 the first release to include baked-in real-time capability.

History

The PREEMPT_RT patchset has been in development since 2005. [3] In 2021, the preemption core locking code was merged. [4] [5]

Since February 2023, Canonical has been releasing real-time versions of Ubuntu Pro, free for personal and small-scale commercial use in up to 5 machines. [6] [7] The real-time kernel can be added to various existing Ubuntu releases through an enablement process. [7] These kernels include the PREEMPT_RT patchset and offer long-term support. [7]

MontaVista Software has been releasing a real-time Linux distribution containing the PREEMPT_RT patchset since the early 2000. Montavista's current main embedded Linux product, CGX, contains real-time preemption as a standard feature.

At the September 2024 European Open Source Summit, Linus Torvalds announced that PREEMPT_RT had been accepted into the mainline Linux kernel after a protracted development hurdle involving the printk kernel logging facility.

References

  1. "20 years later, real-time Linux makes it to the kernel - really". zdnet.com . Retrieved 2024-09-19.
  2. "Merge tag 'sched-rt-2024-09-17' - kernel/git/torvalds/linux.git - Linux kernel source tree". git.kernel.org. Retrieved 2024-09-20.
  3. Reghenzani, Federico; Massari, Giuseppe; Fornaciari, William (2019-02-21). "The Real-Time Linux Kernel: A Survey on PREEMPT_RT". ACM Computing Surveys. 52 (1): 18:1–18:36. doi:10.1145/3297714. hdl: 11311/1076057 . ISSN   0360-0300.
  4. "Realtime preemption locking core merged [LWN.net]". lwn.net. Retrieved 2023-02-09.
  5. "The future of realtime Linux". LWN.net . Retrieved 2023-02-09.
  6. Proven, Liam. "Real-time Ubuntu 22.04: What you need to know". The Register . Retrieved 2023-02-20.
  7. 1 2 3 "Canonical releases Real-time Ubuntu 24.04 LTS". Ubuntu. Retrieved 2024-07-03.