How is hyperthreading handled on amd64?

[Bill Moran]

On Mon, 13 Mar 2006 15:32:51 -0500
John Baldwin <jhb at freebsd.org> wrote:

> On Monday 13 March 2006 15:04, Bill Moran wrote:
> > On Mon, 13 Mar 2006 14:06:34 -0500
> > John Baldwin <jhb at freebsd.org> wrote:
> > 
> > [...]
> > > > I can't argue that the boot messages don't seem to show anything to
> > > > indicate that a second logical CPU was found.
> > > 
> > > Grab the dmesg from /var/run/dmesg.boot rather than /var/log/messages
> > > please.
> > 
> > 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 6.0-RELEASE-p5 #1: Fri Mar 10 16:57:56 EST 2006
> >     root@:/usr/obj/usr/src/sys/DB64
> > Timecounter "i8254" frequency 1193182 Hz quality 0
> > CPU: Intel(R) Xeon(TM) CPU 3.00GHz (2992.71-MHz K8-class CPU)
> >   Origin = "GenuineIntel"  Id = 0xf41  Stepping = 1
> >   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>
> >   Features2=0x641d<SSE3,RSVD2,MON,DS_CPL,CNTX-ID,CX16,<b14>>
> >   AMD Features=0x20000800<SYSCALL,LM>
> >   Hyperthreading: 2 logical CPUs
> > real memory  = 2147221504 (2047 MB)
> > avail memory = 2066378752 (1970 MB)
> > ACPI APIC Table: <DELL   PE BKC  >
> > FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
> >  cpu0 (BSP): APIC ID:  0
> >  cpu1 (AP): APIC ID:  1
> 
> This is a dmesg from an SMP kernel this time. :)
> 
> Can you provide the output from 'sysctl machdep'?

machdep.adjkerntz: 18000
machdep.disable_rtc_set: 0
machdep.wall_cmos_clock: 1
machdep.acpi_timer_freq: 3579545
machdep.acpi_root: 1038016
machdep.disable_mtrrs: 0
machdep.cpu_idle_hlt: 1
machdep.hlt_cpus: 2
machdep.panic_on_nmi: 1
machdep.tsc_freq: 2992705365
machdep.i8254_freq: 1193182
machdep.conspeed: 9600
machdep.gdbspeed: 9600
machdep.conrclk: 1843200
machdep.enable_panic_key: 0
machdep.hlt_logical_cpus: 0
machdep.logical_cpus_mask: 2
machdep.hyperthreading_allowed: 0

-- 
Bill Moran
Collaborative Fusion Inc.