I don't think CAT can be used to partition kernel and userspace -- I'm not even sure how you'd go about doing that given that you can (and do) have shared pages between them.
That being said, from our experiments, if you're using userspace network and NVMe drivers the context switch and associated cache pollution is not a problem, since it is happening pretty infrequently (primarily just timer interrupts, and those can be turned off, but we haven't needed to).
I don't think CAT can be used to partition kernel and userspace -- I'm not even sure how you'd go about doing that given that you can (and do) have shared pages between them.
That being said, from our experiments, if you're using userspace network and NVMe drivers the context switch and associated cache pollution is not a problem, since it is happening pretty infrequently (primarily just timer interrupts, and those can be turned off, but we haven't needed to).