arch/x86/Kconfig.cpu v3.0-rc7

M386

386

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, and UMC 486SX-S.  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 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.
- "Pentium-II" for the Intel Pentium II or pre-Coppermine Celeron.
- "Pentium-III" for the Intel Pentium III or Coppermine Celeron.
- "Pentium-4" for the Intel Pentium 4 or P4-based Celeron.
- "K6" for the AMD K6, K6-II and K6-III (aka K6-3D).
- "Athlon" for the AMD K7 family (Athlon/Duron/Thunderbird).
- "Crusoe" for the Transmeta Crusoe series.
- "Efficeon" for the Transmeta Efficeon series.
- "Winchip-C6" for original IDT Winchip.
- "Winchip-2" for IDT Winchips with 3dNow! capabilities.
- "GeodeGX1" for Geode GX1 (Cyrix MediaGX).
- "Geode GX/LX" For AMD Geode GX and LX processors.
- "CyrixIII/VIA C3" for VIA Cyrix III or VIA C3.
- "VIA C3-2" for VIA C3-2 "Nehemiah" (model 9 and above).
- "VIA C7" for VIA C7.

If you don't know what to do, choose "386".

M486

486

Select this for a 486 series processor, either 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.

M586

586/K5/5x86/6x86/6x86MX

Select this for an 586 or 686 series processor such as the AMD K5,
the Cyrix 5x86, 6x86 and 6x86MX.  This choice does not
assume the RDTSC (Read Time Stamp Counter) instruction.

M586TSC

Pentium-Classic

Select this for a Pentium Classic processor with the RDTSC (Read
Time Stamp Counter) instruction for benchmarking.

M586MMX

Pentium-MMX

Select this for a Pentium with the MMX graphics/multimedia
extended instructions.

M686

Pentium-Pro

Select this for Intel Pentium Pro chips.  This enables the use of
Pentium Pro extended instructions, and disables the init-time guard
against the f00f bug found in earlier Pentiums.

MPENTIUMII

Pentium-II/Celeron(pre-Coppermine)

Select this for Intel chips based on the Pentium-II and
pre-Coppermine Celeron core.  This option enables an unaligned
copy optimization, compiles the kernel with optimization flags
tailored for the chip, and applies any applicable Pentium Pro
optimizations.

MPENTIUMIII

Pentium-III/Celeron(Coppermine)/Pentium-III Xeon

Select this for Intel chips based on the Pentium-III and
Celeron-Coppermine core.  This option enables use of some
extended prefetch instructions in addition to the Pentium II
extensions.

MPENTIUMM

Pentium M

Select this for Intel Pentium M (not Pentium-4 M)
notebook chips.

MPENTIUM4

Pentium-4/Celeron(P4-based)/Pentium-4 M/older Xeon

Select this for Intel Pentium 4 chips.  This includes the
Pentium 4, Pentium D, P4-based Celeron and Xeon, and
Pentium-4 M (not Pentium M) chips.  This option enables compile
flags optimized for the chip, uses the correct cache line size, and
applies any applicable optimizations.

CPUIDs: F[0-6][1-A] (in /proc/cpuinfo show = cpu family : 15 )

Select this for:
Pentiums (Pentium 4, Pentium D, Celeron, Celeron D) corename:
-Willamette
-Northwood
-Mobile Pentium 4
-Mobile Pentium 4 M
-Extreme Edition (Gallatin)
-Prescott
-Prescott 2M
-Cedar Mill
-Presler
-Smithfiled
Xeons (Intel Xeon, Xeon MP, Xeon LV, Xeon MV) corename:
-Foster
-Prestonia
-Gallatin
-Nocona
-Irwindale
-Cranford
-Potomac
-Paxville
-Dempsey


MK6

K6/K6-II/K6-III

Select this for an AMD K6-family processor.  Enables use of
some extended instructions, and passes appropriate optimization
flags to GCC.

MK7

Athlon/Duron/K7

Select this for an AMD Athlon K7-family processor.  Enables use of
some extended instructions, and passes appropriate optimization
flags to GCC.

MK8

Opteron/Athlon64/Hammer/K8

Select this for an AMD Opteron or Athlon64 Hammer-family processor.
Enables use of some extended instructions, and passes appropriate
optimization flags to GCC.

MCRUSOE

Crusoe

Select this for a Transmeta Crusoe processor.  Treats the processor
like a 586 with TSC, and sets some GCC optimization flags (like a
Pentium Pro with no alignment requirements).

MEFFICEON

Efficeon

Select this for a Transmeta Efficeon processor.

MWINCHIPC6

Winchip-C6

Select this for an IDT Winchip C6 chip.  Linux and GCC
treat this chip as a 586TSC with some extended instructions
and alignment requirements.

MWINCHIP3D

Winchip-2/Winchip-2A/Winchip-3

Select this for an IDT Winchip-2, 2A or 3.  Linux and GCC
treat this chip as a 586TSC with some extended instructions
and alignment requirements.  Also enable out of order memory
stores for this CPU, which can increase performance of some
operations.

MELAN

AMD Elan

Select this for an AMD Elan processor.

Do not use this option for K6/Athlon/Opteron processors!

MGEODEGX1

GeodeGX1

Select this for a Geode GX1 (Cyrix MediaGX) chip.

MGEODE_LX

Geode GX/LX

Select this for AMD Geode GX and LX processors.

MCYRIXIII

CyrixIII/VIA-C3

Select this for a Cyrix III or C3 chip.  Presently Linux and GCC
treat this chip as a generic 586. Whilst the CPU is 686 class,
it lacks the cmov extension which gcc assumes is present when
generating 686 code.
Note that Nehemiah (Model 9) and above will not boot with this
kernel due to them lacking the 3DNow! instructions used in earlier
incarnations of the CPU.

MVIAC3_2

VIA C3-2 (Nehemiah)

Select this for a VIA C3 "Nehemiah". Selecting this enables usage
of SSE and tells gcc to treat the CPU as a 686.
Note, this kernel will not boot on older (pre model 9) C3s.

MVIAC7

VIA C7

Select this for a VIA C7.  Selecting this uses the correct cache
shift and tells gcc to treat the CPU as a 686.

MPSC

Intel P4 / older Netburst based Xeon

Optimize for Intel Pentium 4, Pentium D and older Nocona/Dempsey
Xeon CPUs with Intel 64bit which is compatible with x86-64.
Note that the latest Xeons (Xeon 51xx and 53xx) are not based on the
Netburst core and shouldn't use this option. You can distinguish them
using the cpu family field
in /proc/cpuinfo. Family 15 is an older Xeon, Family 6 a newer one.

MCORE2

Core 2/newer Xeon

Select this for Intel Core 2 and newer Core 2 Xeons (Xeon 51xx and
53xx) CPUs. You can distinguish newer from older Xeons by the CPU
family in /proc/cpuinfo. Newer ones have 6 and older ones 15
(not a typo)

MATOM

Intel Atom

Select this for the Intel Atom platform. Intel Atom CPUs have an
in-order pipelining architecture and thus can benefit from
accordingly optimized code. Use a recent GCC with specific Atom
support in order to fully benefit from selecting this option.

GENERIC_CPU

Generic-x86-64

Generic x86-64 CPU.
Run equally well on all x86-64 CPUs.

X86_GENERIC

Generic x86 support

Instead of just including optimizations for the selected
x86 variant (e.g. PII, Crusoe or Athlon), include some more
generic optimizations as well. This will make the kernel
perform better on x86 CPUs other than that selected.

This is really intended for distributors who need more
generic optimizations.

X86_PPRO_FENCE

PentiumPro memory ordering errata workaround

Old PentiumPro multiprocessor systems had errata that could cause
memory operations to violate the x86 ordering standard in rare cases.
Enabling this option will attempt to work around some (but not all)
occurrences of this problem, at the cost of much heavier spinlock and
memory barrier operations.

If unsure, say n here. Even distro kernels should think twice before
enabling this: there are few systems, and an unlikely bug.

PROCESSOR_SELECT

Supported processor vendors

This lets you choose what x86 vendor support code your kernel
will include.

CPU_SUP_INTEL

Support Intel processors

This enables detection, tunings and quirks for Intel processors

You need this enabled if you want your kernel to run on an
Intel CPU. Disabling this option on other types of CPUs
makes the kernel a tiny bit smaller. Disabling it on an Intel
CPU might render the kernel unbootable.

If unsure, say N.

CPU_SUP_CYRIX_32

Support Cyrix processors

This enables detection, tunings and quirks for Cyrix processors

You need this enabled if you want your kernel to run on a
Cyrix CPU. Disabling this option on other types of CPUs
makes the kernel a tiny bit smaller. Disabling it on a Cyrix
CPU might render the kernel unbootable.

If unsure, say N.

CPU_SUP_AMD

Support AMD processors

This enables detection, tunings and quirks for AMD processors

You need this enabled if you want your kernel to run on an
AMD CPU. Disabling this option on other types of CPUs
makes the kernel a tiny bit smaller. Disabling it on an AMD
CPU might render the kernel unbootable.

If unsure, say N.

CPU_SUP_CENTAUR

Support Centaur processors

This enables detection, tunings and quirks for Centaur processors

You need this enabled if you want your kernel to run on a
Centaur CPU. Disabling this option on other types of CPUs
makes the kernel a tiny bit smaller. Disabling it on a Centaur
CPU might render the kernel unbootable.

If unsure, say N.

CPU_SUP_TRANSMETA_32

Support Transmeta processors

This enables detection, tunings and quirks for Transmeta processors

You need this enabled if you want your kernel to run on a
Transmeta CPU. Disabling this option on other types of CPUs
makes the kernel a tiny bit smaller. Disabling it on a Transmeta
CPU might render the kernel unbootable.

If unsure, say N.

CPU_SUP_UMC_32

Support UMC processors

This enables detection, tunings and quirks for UMC processors

You need this enabled if you want your kernel to run on a
UMC CPU. Disabling this option on other types of CPUs
makes the kernel a tiny bit smaller. Disabling it on a UMC
CPU might render the kernel unbootable.

If unsure, say N.