12/03/2001 08:24:53, Erwin Rol <[EMAIL PROTECTED]> wrote:
>Won't more registers and bigger registers make task swapping slowwer ?
>So it would be interesting to see a few RT-Linux benchmarks on it
>thats for sure. More interesting things would be if it got the
>APIC enabled , and lnot disabled like on Athlons and non SMP Pentium *
>systems.
>
Normally, when using ( for PIII example ) simd registers ; 8 new 128bits regitsers,
You should use FXSAVE and FXRSTOR to save and restore FPU/MMX and SIMD registers.
These both instruction allow simd usage with context switching accelerated .... but in
order to use
that, the kernel must allow with CR4.OSFXSR bit the simd support and modify his stack
size !
Allowing the use of simd in the kernel is complex, cause of all task
context structure modification and initialisation of CR4 register ... I tried but
failed ..( not enougth time ..sorry).
>Thats a known redhat "anhancement". There is a bug in that kernel that
>crashes
>it when used on a athlon, i beleive it was something with the CPU
>capabilities
mtrr support. ;)
Chris.
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Kumsta christophe
Real-time image processing
RTAI/RTlinux
maf-roda
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