问题
I would like to write real-time Linux programs while using the real-time PREEMPT_RT. I found the official Wiki (https://rt.wiki.kernel.org/index.php/HOWTO:_Build_an_RT-application). There are some code examples but I would like to get the explanation of the possible RT-functions.
Thank you,
回答1:
It is important to underline that PREEMPT_RT is a patch that changes the internal code of the Linux kernel to reduce the maximum latency experienced by a user-level process. This is done by changing e.g. spinlocks to real-time preemptible mutexes, using threaded interrupts (i.e., hardware interrupts handlers run in seperate kernel threads) and so on. Therefore, it doesn't provide any API for user-level programming and you still rely on the standard libc and system call primitives. Just patch, configure and re-install the kernel (or, alternatively, install a pre-built PREEMPT_RT kernel).
You can still, of course, follow good practice real-time programming to avoid delays and contentions. The page you are mentioning concerns how to configure the kernel and write your code to get full benefit from the patch.
If you look for specific real-time APIs, you may want to have a look at Xenomai 3.0.1 which provides a specific API for running your user-level process on top of either the standard Linux or the Xenomai hypervisor (a layer below the Linux kernel)
来源：https://stackoverflow.com/questions/35766811/build-an-rt-application-using-preempt-rt