[CLUE-Tech] Which RedHat SMP Version

[Matt Gushee]

On Thu, Jun 19, 2003 at 09:19:08AM -0600, Gary Threlkeld wrote:
> 
> OTOH, I thought that PII's were considered i586 generation
> processors.

That may depend who's doing the considering. In one sense, they're still
all i386s.

> 2)  Help me understand the differences in the kernels.  Are
>      there going to be catastrophic problems (damage) if I
>      attempt to use the wrong one or just performance issues?

Older hands than I may know better, but as far as I know the worst thing
that could happen is that your machine could become unbootable. I'm not
sure performance is that much of an issue. In my experience it's more
likely that the system won't boot, or will be horribly slow (indicating
more serious underlying problems), than to be "a bit sluggish."

> 3)  For future reference... are there "concrete rules" to apply
>      do help decide which kernel series i386, i486, etc to use 
>      with a processor series PII, PIII, P4, etc.?

If you're looking for RedHat-specific info, I'll let others handle that.
But for generic kernels (i.e. if you're compiling it yourself) it's
pretty clearly documented. The following is from the kernel
configuration help file:


  CONFIG_M386
    This is the processor type of your CPU. This information is used for
    optimizing purposes. In order to compile a kernel that can run on
    all x86 CPU types (albeit not optimally fast), you can specify
    "386" here.
  
    The kernel will not necessarily run on earlier architectures than
    the one you have chosen, e.g. a Pentium optimized kernel will run on
    a PPro, but not necessarily on a i486.
  
    Here are the settings recommended for greatest speed:
     - "386" for the AMD/Cyrix/Intel 386DX/DXL/SL/SLC/SX, Cyrix/TI
       486DLC/DLC2, UMC 486SX-S and NexGen Nx586.  Only "386" kernels
       will run on a 386 class machine.
     - "486" for the AMD/Cyrix/IBM/Intel 486DX/DX2/DX4 or
       SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S.
     - "586" for generic Pentium CPUs, possibly lacking the TSC
       (time stamp counter) register.
     - "Pentium-Classic" for the Intel Pentium.
     - "Pentium-MMX" for the Intel Pentium MMX.
     - "Pentium-Pro" for the Intel Pentium Pro/Celeron/Pentium II.
     - "Pentium-III" for the Intel Pentium III
       and Celerons based on the Coppermine core.
     - "Pentium-4" for the Intel Pentium 4.
     - "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
     - "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
     - "Elan" for the AMD Elan family (Elan SC400/SC410).
     - "Crusoe" for the Transmeta Crusoe series.
     - "Winchip-C6" for original IDT Winchip.
     - "Winchip-2" for IDT Winchip 2.
     - "Winchip-2A" for IDT Winchips with 3dNow! capabilities.
     - "CyrixIII" for VIA Cyrix III or VIA C3.
  
    If you don't know what to do, choose "386".
  
  486
  CONFIG_M486
    Select this for a x486 processor, ether Intel or one of the
    compatible processors from AMD, Cyrix, IBM, or Intel.  Includes DX,
    DX2, and DX4 variants; also SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or
    U5S.
  
  586/K5/5x86/6x86/6x86MX
  CONFIG_M586
    Select this for an x586 or x686 processor such as the AMD K5, the
    Intel 5x86 or 6x86, or the Intel 6x86MX.  This choice does not
    assume the RDTSC instruction.
  
  Pentium Classic
  CONFIG_M586TSC
    Select this for a Pentium Classic processor with the RDTSC (Read
    Time Stamp Counter) instruction for benchmarking.
  
-- 
Matt Gushee                 When a nation follows the Way,
Englewood, Colorado, USA    Horses bear manure through
mgushee at havenrock.com           its fields;
http://www.havenrock.com/   When a nation ignores the Way,
                            Horses bear soldiers through
                                its streets.
                                
                            --Lao Tzu (Peter Merel, trans.)