Twin CPU machine running with only one cpu?

[I-Humphrey, Brendon]

All,

I'm the originator of the thread, posting from work, using outlook -
apologies if this comes out as html!!

Anyway, to clarify the machine has two physical CPUs (4 HTT cores), this
is shown clearly in the ACPI dump of the processors. Linux sees this
machine as a 2 cpu machine (or 4 if the SMP code is initialised
explicitly from ACPI).

Previous versions of FreeBSD have not identified the HTT cores, rather
have picked up the two physical CPUs and run with that. I was around
when the machdep.c changes went in (for 4.8) that were supposed to
identify HTT cores, but they didn't work on this machine due to the MP
Table being a bit strange in the way that it enumerates the cores IIRC.

What I am wondering, if subsequent changes to the machdep code have
altered the behaviour in such a way that the OS is now picking up the
first physical CPU and its HTT core, and ignoring the others. That would
account for the weird load/scheduling behaviour.

If I have time, I might go wading through the machdep code this evening
to see what it does/how it differs from the past...

Anyone?

Cheers,
Brendon