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

From: Juergen Beisert <juergen127@kreuzholzen.de>
To: Rene Herman <rene.herman@keyaccess.nl>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFT] Port 0x80 I/O speed
Date: Wed, 12 Dec 2007 16:12:25 +0100	[thread overview]
Message-ID: <200712121612.25974.juergen127@kreuzholzen.de> (raw)
In-Reply-To: <475FF094.8000709@keyaccess.nl>

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