2005-05-24 17:12:23

by Oskar Liljeblad

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Subject: clock drift with 2x Promise Ultra133 TX2 (PDC 20269) (again)

Problem:
I have two Promise Ultra133 TX2 (PDC 20269) cards, each with two
Maxtor UDMA133 hard drives connected. The system also has another
hard drive connected to the motherboard. A total of five drives.

When I concurrently read from two hard drives connected to
different Promise cards, there is heavy software clock drift.
The software clock runs too fast - approx. a few seconds per
minute during this i/o. To reproduce:

hwclock --hctosys
hwclock --show
date
dd if=/dev/hde of=/dev/null bs=1M count=7200 &
dd if=/dev/hdi of=/dev/null bs=1M count=7200 &
wait
wait
hwclock --show
date

This doesn't happen if I read from two drives connected to the
same card, or one drive connected to the motherboard and one
connected to a Promise card.

I've removed all other PCI devices in the system - problem remains.
I tried different motherboards:

Asus A7V266-C with AMD AthlonXP 2000+ (i686) - problem occurs
Asus A7V600-X with AMD Sempron 2600+ (i686) - problem occurs
Abit KV8 Pro with AMD Athlon64 3000+ (i686) - problem does not occur!

So what makes the Abit motherboard different?

Regards,

Oskar Liljeblad ([email protected])


2005-05-24 17:26:37

by Drew Winstel

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Subject: Re: clock drift with 2x Promise Ultra133 TX2 (PDC 20269) (again)

On Tue, 2005-05-24 at 18:53 +0200, Oskar Liljeblad wrote:

> Asus A7V266-C with AMD AthlonXP 2000+ (i686) - problem occurs
> Asus A7V600-X with AMD Sempron 2600+ (i686) - problem occurs
> Abit KV8 Pro with AMD Athlon64 3000+ (i686) - problem does not occur!
>
> So what makes the Abit motherboard different?
>

Are you running the AMD64 machine on a 32- or 64-bit distribution?

That was just the first thought that came into my head.

Drew