Let's say I have some multi-core ARM Cortex-A.
Now I have there a Linux, with RT_PREEMPT patch (so called real-time Linux). I run a processes with affinity set to one core and high priority (above 50).
Thanks to real-time patch, even the kernel scheduler cannot preempt my process, and thanks to affinity it can run all the time on a single core (and OS on others).
In such conditions, is there any difference (i.e. overhead) of running such code on Linux vs bare-metal?
Will the performance be the same? If not, why?