[gentoo-amd64] Hyper-threading an AMD64 3800+

[Greg]

I've been having trouble determining if my processor has hyper-threading. I'm thinking that it does. I know that it isn't 
a dual-core.

If it is a hyper-thread processor, I can't seem to figure out exactly how to enable the hyper-thread under linux.

First, here's the CPU info from /proc/cpuinfo

processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 15
model		: 95
model name	: AMD Athlon(tm) 64 Processor 3800+
stepping	: 2
cpu MHz		: 1000.000
cache size	: 512 KB
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow up rep_good pni cx16 lahf_lm svm extapic cr8_legacy
bogomips	: 2009.87
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts fid vid ttp tm stc


I have the gentoo genkernel sources version 2.6.28-r5 currently installed. 
The > processor section looks like this:
  . .  [*] Tickless System (Dynamic Ticks)  . .
  . .  [*] High Resolution Timer Support . .
  . .  [*] Symmetric multi-processing support . .
  . .  [*] Enable MPS table . .
  . .  Subarchitecture Type (PC-compatible)  ---> . .
  . .  [ ] Paravirtualized guest support ---> . .
  . .  [ ] Memtest . .
  . .  Processor family (Opteron/Athlon64/Hammer/K8)  ---> . .
  . .  [ ] Supported processor vendors ---> . .
  . .  [*] Enable DMI scanning . .
  . .  [*] GART IOMMU support . .
  . .  [*] IBM Calgary IOMMU support . .
  . .  [*] Should Calgary be enabled by default?  . .
  . .  [*] AMD IOMMU support . .
  . .  (32) Maximum number of CPUs (2-512)  . .
  . .  [*] SMT (Hyperthreading) scheduler support . .
  . .  [*] Multi-core scheduler support . .
  . .  Preemption Model (Preemptible Kernel (Low-Latency Desktop))  ---> . .
  . .  [ ] Preemptible RCU . .
  . .  [*] Machine Check Exception . .
  . .  [*] Intel MCE features . .
  . .  [*] AMD MCE features . .
  . .  < > Dell laptop support . .
  . .  <M> /dev/cpu/microcode - microcode support . .
  . .  [*] Intel microcode patch loading support . .
  . .  [*] AMD microcode patch loading support . .
  . .  <*> /dev/cpu/*/msr - Model-specific register support . .
  . .  <*> /dev/cpu/*/cpuid - CPU information support . .
  . .  [ ] Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)  . .
  . .  Memory model (Sparse Memory)  ---> . .
  . .  [*] Sparse Memory virtual memmap . .
  . .  *** Memory hotplug is currently incompatible with Software Suspend *** . .
  . .  [*] Add LRU list to track non-evictable pages . .
  . .  [ ] Check for low memory corruption . .
  . .  [*] Reserve low 64K of RAM on AMI/Phoenix BIOSen . .
  . .  [*] MTRR (Memory Type Range Register) support . .
  . .  [*] MTRR cleanup support . .
  . .  (0)  MTRR cleanup enable value (0-1)  . .
  . .  (1)  MTRR cleanup spare reg num (0-7)  . .
  . .  [ ] x86 PAT support . .
  . .  [ ] EFI runtime service support . .
  . .  [*] Enable seccomp to safely compute untrusted bytecode . .
  . .  Timer frequency (300 HZ)  ---> . .
  . .  [*] kexec system call . .
  . .  [ ] kernel crash dumps . .
  . .  (0x200000) Physical address where the kernel is loaded . .
  . .  [ ] Build a relocatable kernel (EXPERIMENTAL)  . .
  . .  -*- Support for hot-pluggable CPUs . .
  . .  [*] Compat VDSO support . .
  . .  [ ] Built-in kernel command line . .
  . .........................

I'm sure there are things that should be left out of my kernel as my AMD probably doesn't support them or need them, but I 
have left various things enabled where I wasn't sure.

Any suggestions or thoughts are welcome. Like I said, I'm pretty sure it should have hyperthreading, but it doesn't show 
it in the current configuration and all searches have yielded unhelpful results.