Subject: Re: iBook G4 wrong cpu speed detection
To: Mathias Monnerville <mathias.monnerville@paris4.sorbonne.fr>
From: Michael <macallan18@earthlink.net>
List: port-macppc
Date: 05/24/2005 07:35:57
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Hello,

> my iBook G4 seems to be rather slow at compile time. The processor is
> a 1GHz model but the kernel detects it as a 534MHz. Why ?

Almost certainly because it's running at 534 MHz at this point.

> Does the kernel just read hardcoded information somewhere or is there
> an issue to fix cpu detection ?

The problem is that OpenFirmware doesn't start the CPU at full speed
( which is a good thing when there's no power management or anything
like that active ) and the NetBSD kernel doesn't know how to change
that. Just run a couple of CPU-bound benchmarks on both NetBSD and MacOS
X and you'll see what I mean.=20
Another problem is that NetBSD still can't put this kind of CPU to sleep
when idle so it won't cool down - running at full speed we'd have a
problem I guess, at least on some machines. Too bad I don't know nearly
enough PowerPC assembler to fix that.

have fun
Michael


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