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With the current Version 5.10 of a vanilla linux kernel, one can configure the kernel as a low-latency version as the mainline have accepted multiple merge requests from the Preempt-rt patch team. However if one patch the vanilla kernel with it's related preempt-rt patch version, one can configure the kernel as fully preemptable.

But what does change with this fully preemtable config?

  • Are the hard IRQ part (top half /critical section) of a interrupt handler also preemptable now?

Does anyone have a link to a proper paper or documentation, as i did not find anything searching on the official Wiki page of the linux foundation website, neither i have found a paper on ieee xplore.

I thank you beforehand for your help.

sirius
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1 Answers1

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Fortunately perseverance pays off. I have found the proper documentation on the Linux Foundation website.

https://wiki.linuxfoundation.org/realtime/documentation/technical_basics/preemption_models

Which gives a nice overview. From this documentation i think the hard IRQ part is still not preemptable.

sirius
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  • Correct me if I'm wrong, but I don't think hard IRQ can possibly be preempted, and it will never ever happen on x86 based architectures. – Antoine Viallon Sep 29 '22 at 12:40