Can I disable HyperThreading in OS?

[Andrew P.]

On 10/7/05, hshh <hunreal at gmail.com> wrote:
> My /boot/loader.conf,
>    userconfig_script_load="YES"
>    kern.ipc.nmbclusters="65536"
>
>  I sure there are only 2 physical processors inside the box.
>  Attached dmesg infomation.
>  -----------------------------------------
>  Copyright (c) 1992-2005 The FreeBSD Project.
>  Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
>          The Regents of the University of California. All rights reserved.
>  FreeBSD 4.11-RELEASE-p12 #1: Fri Sep 30 17:05:26 CST 2005
>      root at www.sa20.com:/usr/obj/usr/src/sys/www
>  Timecounter "i8254"  frequency 1193182 Hz
>  CPU: Intel(R) Xeon(TM) CPU 1.80GHz (1794.19-MHz 686-class CPU)
>    Origin = "GenuineIntel"  Id = 0xf27  Stepping = 7
>
> Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
>    Hyperthreading: 2 logical CPUs
>  real memory  = 2146959360 (2096640K bytes)
>  avail memory = 2087632896 (2038704K bytes)
>  Programming 24 pins in IOAPIC #0
>  IOAPIC #0 intpin 2 -> irq 0
>  Programming 24 pins in IOAPIC #1
>  Programming 24 pins in IOAPIC #2
>  FreeBSD/SMP: Multiprocessor motherboard: 4 CPUs
>   cpu0 (BSP): apic id:  0, version: 0x00050014, at 0xfee00000
>   cpu1 (AP):  apic id:  1, version: 0x00050014, at 0xfee00000
>   cpu2 (AP):  apic id:  6, version: 0x00050014, at 0xfee00000
>   cpu3 (AP):  apic id:  7, version: 0x00050014, at 0xfee00000
>   io0 (APIC): apic id:  2, version: 0x00178020, at 0xfec00000
>   io1 (APIC): apic id:  3, version: 0x00178020, at 0xfec80000
>   io2 (APIC): apic id:  4, version: 0x00178020, at 0xfec80400
>  Preloaded elf kernel "kernel" at 0xc02e6000.
>  ....
>  SMP: AP CPU #1 Launched!
>  SMP: AP CPU #3 Launched!
>  SMP: AP CPU #2 Launched!

Please, cc freebsd-questions and append your answers,
don't prepend them.

Post your kernel config as well please. I have very little
experience with SMP systems, but someone from the
list would probably like to look into your problem.