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SubjectRe: SYSENTER based syscalls patch, 2.1.105, RFC

On Thu, 18 Jun 1998, Andrea Arcangeli wrote:

> > [mingo@hal fastcall]$ ./fastcall
> > (INT $0x80 based getpid(), got pid 497) latency:282 cycles
> > (SYSENTER based getpid(), got pid 497) latency:138 cycles
>
> andrea@dragon:~$ ./a.out
> (INT $0x80 based getpid(), got pid 949) latency:115 cycles
> Illegal Instruction
> [...]
>
> On my 266 Mhz P5MMX I am going faster than your PII?!?! I am using a #SMP
> (no-SMP ;-) kernel but this should not change nothing since the test is
> done outside the kernel code...

yep. It's probably because on the PII it's more expensive to do
segmentation related stuff. And call gates (int $0x80) do _alot_ of that
stuff ...

-- mingo


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