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Date: Fri, 12 Dec 2003 23:58:22 +0900
From: Rob <nospam@users.sourceforge.net>
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Subject: Need help: HyperThreading-CPU + FreeBSD-Stable + Multi-threading
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Hello,

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:

   machdep.hlt_logical_cpus="0"

After that, I'm done with the hyperthreading?

Thanks,
Rob.

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!