Subject: AMD CPU performance rating (was Re: -current broken)
To: Arto Huusko <firstname.lastname@example.org>
From: Bang Jun-Young <email@example.com>
Date: 11/04/2003 15:18:05
On Tue, Nov 04, 2003 at 01:40:37AM +0200, Arto Huusko wrote:
> On Mon, 3 Nov 2003, Bang Jun-Young wrote:
> > On Sun, Nov 02, 2003 at 05:26:19PM -0500, Steve Rumble wrote:
> > > On Sun, Nov 02, 2003 at 02:05:13PM -0700, Bruce J.A. Nourish wrote:
> > > > cpu0 at mainbus0: (uniprocessor)
> > > > cpu0: AMD Athlon XP 2100+ (686-class), 1300.12 MHz, id 0x681
> > >
> > > This is off-topic, but is your CPU underclocked? I'm not sure
> > > how the identification mechanism works, but a 2100+ should be
> > > reported at close to 1.73ghz.
> > The PR number is determined by the BIOS, and clock frequency by the
> > kernel. It seems that something is broken with the process identification
> > in this case.
> Not necessarily. If the clock or bus (or something, I forget) speed
> is not set correctly in BIOS, the processor is run underclocked.
> That naturally affects the processor speed, but oddly it also affects
> the identification.
Performance rating formula for Thoroughbred cores:
PR = 3 * freq / 2 - 500 (stepping A)
PR = 3 * freq / 2 - 600 (stepping B)
> E.g. I have 2400+, but the default bus speed in the BIOS is 100MHz.
> In that case, NetBSD claims I have 2100+ (and the corresponding
> GHz) . When I change the speed in BIOS to 133MHz, the processor is
> correctly identfied as 2400+@2GHz.
Your BIOS seems to do the math just fine. :-)
What I'm wondering is a formula 2100+@1300Mhz was obtained from. Even
my Palomino processor is rated 1800+@1533Mhz.
Bang Jun-Young <junyoung@NetBSD.org>