HyperThreading CPU's

[Bharat Mediratta]

From: "Dan Rue" <drue at therub.org>
...
> 20031022:
>         Support for HyperThread logical CPUs has now been enabled by
>         default.  As a result, the HTT kernel option no longer exists.
>         Instead, the logical CPUs are always started so that they can
>         handle interrupts.  However, the extra logical CPUs are prevented
>         from executing user processes by default.  To enable the logical
>         CPUs, change the value of the machdep.hlt_logical_cpus from 1 to
>         0.  This value can also be set from the loader as a tunable of
>         the same name.

Does 4.9 actually make effective use of HTT?  I read recently (can't
remember where, but I can probably find it if pressed) that in 4.8
enabling HTT was probably going to cause performance degradatation 
due to locking issues in the kernel.  I've been itching to upgrade
to 5.x to get more value out of my MP+HTT box, but don't want to 
upgrade until it's production release quality.

If the 4.9 kernel really takes advantage of HTT, that would be worth
upgrading for, IMO.

-Bharat