Re: [RFT] Port 0x80 I/O speed

From: Juergen Beisert
Date: Wed Dec 12 2007 - 10:12:39 EST


On Wednesday 12 December 2007 15:30, Rene Herman wrote:
> On 12-12-07 09:59, Juergen Beisert wrote:
> > $ for i in `seq 5`; do ./port80; sleep 1; done
> > cycles: out 5260, in 2372
> > cycles: out 5260, in 2384
> > cycles: out 5260, in 2323
> > cycles: out 5270, in 2382
> > cycles: out 5259, in 2323
> >
> > $ cat /proc/cpuinfo
> > processor : 0
> > vendor_id : GenuineIntel
> > cpu family : 6
> > model : 7
> > model name : Pentium III (Katmai)
> > stepping : 3
> > cpu MHz : 501.208
>
> This one's really wrong. This would be 10 microsecs. I suppose the
> machine/bus was heavily loaded or something?

Ups, your are right:

$ cat /proc/acpi/processor/CPU0/throttling
state count: 2
active state: T1
states:
T0: 00%
*T1: 50%

With T0 it get:

$ for i in `seq 5`; do ./port80; sleep 1; done
cycles: out 684, in 280
cycles: out 684, in 280
cycles: out 684, in 280
cycles: out 684, in 280
cycles: out 684, in 280

Juergen
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