Xeon, Hyperthreading and SMP

[Lucky Leavell]

I have a customer with a dual Xeon 3Ghz system with OSR5.0.7 Enterprise
installed. The system reports four CPUs present instead of two and he has
to install four SMP licenses to (shouldn't that be three?) to make use of
all "four". Is this normal behavior - to require a SMP license to make
use of hyperthreading or does he need to install a patch or something. (A
search of TAs turned up no mention of Xeon or hyperhtreading and the only
thread in this NG suggested turning hyperthreading off in the BIOS.)

Thank you,
Lucky

Lucky Leavell Phone: (800) 481-2393 (US/Canada)
UniXpress - Your Source for SCO OR: (812) 366-4066
1560 Zoar Church Road NE FAX: (812) 366-3618
Corydon, IN 47112-7374 Email: [email]lucky@UniXpress.com[/email]
WWW Home Page: [url]http://www.UniXpress.com[/url]

[Bela Lubkin]

Lucky Leavell wrote:

> I have a customer with a dual Xeon 3Ghz system with OSR5.0.7 Enterprise
> installed. The system reports four CPUs present instead of two and he has
> to install four SMP licenses to (shouldn't that be three?) to make use of
> all "four". Is this normal behavior - to require a SMP license to make
> use of hyperthreading or does he need to install a patch or something. (A
> search of TAs turned up no mention of Xeon or hyperhtreading and the only
> thread in this NG suggested turning hyperthreading off in the BIOS.)

OpenServer 5.0.7 Update Pack 1, coming out soon, adds support for
HyperThreading. In particular, it makes the licensing aware of HT so
that only one license per physical CPU is required. For your customer,
that would be 1 base license + 1 SMP license.

For systems without OSR507UP1 installed, the best recommendation is to
disable HT in BIOS setup. The OS doesn't expect to see those extra CPUs
and really has no idea what to do with them.

Systems with a single HT CPU and OSR507UP1 can install SMP (without an
SMP license) and take advantage of both "halves" of the CPU. My new
workstation is configured this way...

>Bela<