That's a very good point, unfortunately I don't have a clear answer.
I'm aware of the problem with grep and this patch definitely not resolves it.

Yet another reincarnation of https://reviews.freebsd.org/rS302292 this time in peak_clear_sc
If no objections, I will commit this next week.

Closed by https://svnweb.freebsd.org/changeset/base/336128

Here is my two cents.

We'll handle the BE part.

Looks OK, we'll test it on our hardware.

I think we talked out all issues here.
I'll split this to separate patches and commit to the HEAD. Please let me know if you have any objections.

Actually, this is the only way to release resources by idling CPUs within the same SMT group - Linux does the same.
Sleep mode used here has the shortest wakeup delay, so the only performance hit is from saving and restoring context. However, it's still less complex than the one in cpu_switch.

Nice!

It SHOULD work on PowerNV as the code for cpuid swap is there, however I did not run much of testing, so I'd rather consider this as experimental/not-working. The CHRP platform has no such code, so there the BSP must be at CPU0.

Any objections for commiting this?

Sounds reasonable. I've removed all references to PIR and left the previous PCPU-assignment mechanism intact.

Yes, the recent toolchain works well.

It's already outdated

Merged as r302292

Closed by
https://svnweb.freebsd.org/changeset/base/328042

Please let me know if there are any objections to this patch. I'd like to have it commited on Monday.