Need help: HyperThreading-CPU + FreeBSD-Stable + Multi-threading

Stefan Cars stefan at
Sat Dec 13 11:58:07 PST 2003


This is strange, my system doesn't even show mchdep.hlt_logical_cpus, very
weird. My system have HT


-----Original Message-----
From: owner-freebsd-questions at
[mailto:owner-freebsd-questions at] On Behalf Of Rob
Sent: den 12 december 2003 15:58
To: freebsd-questions at
Subject: Need help: HyperThreading-CPU + FreeBSD-Stable + Multi-threading


Recently I've got a new PC: P4 Titan 2.6 GHz.
It says in the brochure that it has "HyperThreading", which I think is
somehow related to the HyperThread thing in the FreeBSD kernel, right?

I know there's this message in /usr/src/UPDATING, which unfortunately does
not clear up the matter for me.

So let me recap what I believe to understand:

For utilizing the advantages of this HyperThreading stuff for users, I
need in the kernel configuration:
   options        SMP        # Symmetric MultiProcessor Kernel
   options        APIC_IO    # Symmetric (APIC) I/O

Furthermore, I need to set "machdep.hlt_logical_cpus" to 0 (zero).
How do I add this to "the loader" so that it is set to zero at every
boot up? Should I simply add to my /boot/loader.conf a line like:


After that, I'm done with the hyperthreading?


PS: if you're in the mood, I would appreciate a few words on what this
HyperThreading is about and what advantages I can expect. Thanks too!

freebsd-questions at mailing list
To unsubscribe, send any mail to "freebsd-questions-unsubscribe at"

More information about the freebsd-questions mailing list