amd64 webpage, 12GB memory? 64-bit or not? SMP or not?

[Jeremy C. Reed]

On Fri, 17 Mar 2006, Steve Kargl wrote:

> > How can I tell if a 2.80Ghz Xeon is a 32-bit Xeon or a 64-bit Xeon? What 
> > do I look for in the 6.0-RELEASE GENERIC i386 dmesg output? I do see:
> > 
> > ACPI APIC Table: <PTLTD          APIC  >
> > Timecounter "i8254" frequency 1193182 Hz quality 0
> > CPU: Intel(R) Xeon(TM) CPU 2.80GHz (2793.01-MHz 686-class CPU)
>                                                   ^^^^^^^^^^^^^
> You're running a i386 kernel, which is 32-bit.

I already know what it is currently running. In my email, I tried to 
indicate that it is running 6.0-RELEASE GENERIC i386 (twice in the parts 
you included in your reply).

I am unclear if you are answering my question: How can I tell if a 2.80Ghz 
Xeon is a 32-bit Xeon or a 64-bit Xeon?

> > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,C
> > MOV,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=0x20100000<NX,LM>
> >   Hyperthreading: 2 logical CPUs
> > real memory  = 3489071104 (3327 MB)
> > avail memory = 3414630400 (3256 MB)
> > 
> > How can I tell if it can take advantage of "options SMP" (from looking at 
> > 6.0-RELEASE i386 GENERIC output)? (I do see "Hyperthreading: 2 logical 
> > CPUs".)
> 
> You're using a GENERIC kernel.  IIRC, "options SMP" isn't included
> in GENERIC, so you're running a UP kernel.  You need to rebuild
> the kernel

I understand. I know it is running GENERIC as I mentioned. My question is:
How can I tell if it can take advantage of "options SMP" (from looking at
6.0-RELEASE i386 GENERIC output)?

> > I was told it has 12 GB of memory. The Hardware Notes also says "The 
> > largest tested memory configuration to date is 8GB." But I only see "real 
> > memory = 3489071104 (3327 MB)".
> 
> The i386 is limited to 4 GB address space without options PAE.  You
> need to rebuild your kernel.

Only i386 supports "options PAE". How can I tell if this system can 
support an amd64 (without physical access)?

I am still unsure. Sorry if I misunderstood your reply. I know I am 
currently running a 6.0-RELEASE i386 GENERIC kernel. (And I know SMP is 
not in GENERIC). I want to know how I can find out if I should be running 
an amd64 kernel instead.

I was under the impression that some (all?) 64 bit Athlons, Opterons, 
Xeons can also run the 32-bit i386 kernel. (I was sure I have seen this 
too.)

I have been looking at src/sys/i386/i386/identcpu.c. But I am not sure how 
an 64-bit Intel Xeon would behave. (I am guessing it would be 
CPUCLASS_686.)

I do see that my dmesg output has AMD featuress with "LM" which means 
64-bit long mode. But I don't know if that means this is a 64-bit system.

I see the dmesg says "Id = 0xf43" (this is the cpu_id). Doing some google 
searches show one "K8-class" and several "686-class" CPUs. Also NYCBUG's 
dmesg database has that same "K8-class" "Id = 0xf43" system. A "K8-class" 
is definitely from an amd64 kernel (as it is printed from the 
src/sys/amd64/amd64/identcpu.c).

I am hoping the system I am looking at can run the amd64 kernel.

Thanks for your reply. You got me searching into the kernel source now.

 Jeremy C. Reed

echo '9,J8HD,fDGG8B@?:536FC5=8 at I;C5?@H5B0D at 5GBIELD54DL>@8L?:5GDEJ8LDG1' |\
sed ss,s50EBsg | tr 0-M 'p.wBt SgiIlxmLhan:o,erDsduv/cyP'