Dual core AMD64 4400+ X2 works fine on Abit AV8

[Jung-uk Kim]

On Wednesday 21 September 2005 04:59 pm, Alexander Konovalenko wrote:
> On Wednesday 21 September 2005 17.37, Attila Nagy wrote:
> > Alexander Konovalenko wrote:
> > > 2) recompiled and installed 5.4-STABLE kernel with "options
> > > SMP", then I tested it with old single core CPU
> > > CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4400+
> > > (2247.42-MHz K8-class CPU) Origin = "AuthenticAMD"  Id =
> > > 0x20f32  Stepping = 2
> > > Features=0x178bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP
> > >,MTRR,PGE, MCA,C MOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2,HTT>
> > >   Features2=0x1<SSE3>
> > >   AMD
> > > Features=0xe2500800<SYSCALL,NX,MMX+,<b25>,LM,3DNow+,3DNow>
> > > Hyperthreading: 2 logical CPUs
> >
> > Can this "I see hyperthreading, while there is no hyperthreading"
> > cause performance degradation, for example by HTT defaults to off
> > in the recent 5.x builds?

If you are using 6.0 or above, you can try this patch:

http://people.freebsd.org/~jkim/multicore.diff

I believe the old patch still applies to 5.4:

http://docs.freebsd.org/cgi/mid.cgi?200505182007.28631.jkim

Jung-uk Kim

> I just made some grep in /usr/src and
> found /usr/src/sys/amd64/amd64/identcpu.c, near the line #293:
> .....
>                         /*
>                          * If this CPU supports hyperthreading then
> mention * the number of logical CPU's it contains. */
>                         if (cpu_feature & CPUID_HTT &&
>                             (cpu_procinfo & CPUID_HTT_CORES) >> 16
> > 1) printf("\n  Hyperthreading: %d logical CPUs", (cpu_procinfo &
> CPUID_HTT_CORES) >> 16); ...
>
> I don't know all details but seem that cpu_feature contain
> CPUID_HTT bit....

Yes, it does.  Backward compatibility...

Jung-uk Kim

> /Alexander Konovalenko
>
> +46-8-5537-8142 (office)
> +46-7-3752-2116
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>
> Royal Institute of Technology (KTH)
> Nanostructure Physics Department, Albanova
> Roslagstullsbacken 21
> 10691 Stockholm
> Sweden
>
>
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