My experimental environment is Linux6.1, and the real-time patch preempt_rt has been applied to improve the real-time performance of the network.
I checked the relevant papers and saw a lock mentioned in the paper, as shown by the arrow in the attached picture (the original link is here: https://ieeexplore.ieee.org/document/8501912/citations?tabFilter=papers#citations)
The paper shows that when the interrupt processing thread of the network card driver enters the softirq mechanism of the CPU, the thread will try to acquire the softirq_lock lock.
However, I did not find a variable named softirq_lock in the source code. Can anyone tell me what the name of this lock is in the source code? Thank you! ! This has been bothering me for two months
I'm no Linux expert, but have you tried looking at:
https://www.kernel.org/doc/html/v6.1/kernel-hacking/locking.html
There's quite a bit about soft irq locking there.
Other than that, I'd google 'linux 6.1 forums' and try looking or asking on the forums that turn up there. Apologies if you've already tried these things!
You're welcome. The article you linked apparently presents a new approach to solving a problem known as 'priority inversion', which can lead to unexpected delays or latencies for multi-tasking systems. This can be a significant problem in real-time applications, in which the system is required to respond to events within a hard time-limit. So it might be worth looking up 'priority inversion' in any textbooks or online resources to get a background understanding on that problem if it is new to you.
Presumably, the real-time patch preempt_rt you mentioned is a fix to the kernel to improve real-time performance by fixing or mitigation priority-inversion issues.
The article I linked to discusses another feature of multi-tasking kernels, critical code-section locking or resource locking. In simple multi-tasking systems, locks can cause priority inversion to occur.
The forums usually have a search feature, so you might find that someone else has already answered a very similar question to yours on the forum. The forums will have information that is very specific to the version of linux you are working with, which might get you the information you need more quickly.
Hope this helps!