APIC/SMP on UP? (was Re: Load average with CURRENT)

[Conrad Sabatier]

On 07-Mar-2004 Justin Dossey wrote:
> On Sun, 7 Mar 2004, Andre Guibert de Bruet wrote:
>>
>> Is this a system with multiple CPUs or a P4 with hyperthreading? It could
>> be that you didn't previously have the APIC and SMP (or hyperthreading)
>> options enabled in your kernel and now you do... Could you paste the first
>> 15 lines of the output of "top -S"?
> 
> It's a single CPU AMD Duron 1.3GHz, with SMP disabled, but APIC
> enabled.

I've been meaning to ask about this.  Is there anything to be gained on a UP
box by enabling APIC and/or SMP?  I'm running on an Athlon here, with ULE:

CPU: AMD Athlon(tm) Processor (998.07-MHz 686-class CPU)
  Origin = "AuthenticAMD"  Id = 0x622  Stepping = 2
  Features=0x183f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PA
T,PSE36,MMX,FXSR>
  AMD Features=0xc0400000<AMIE,DSP,3DNow!>

-- 
Conrad Sabatier <conrads at cox.net> - "In Unix veritas"