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From: Robert Watson <rwatson@FreeBSD.org>
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To: Arne WXrner <arne_woerner@yahoo.com>
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cc: freebsd-performance@freebsd.org
Subject: Re: FreeBSD 5.3 I/O Performance / Linux 2.6.10 | Continued
	Discussion
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On Thu, 3 Feb 2005, Arne WXrner wrote:

> I just tested R5.1 with a
>   time -c "dd if=/dev/zero of=a bs=64k count=1000 ; fsync a"  and it was
> 4 or about 4 times fast than with R5.3. 
> 
> Is it smart to start looking for regressive changes in sys/dev/ata or in
> /sys/kern? 
> 
> I mean: Did somebody see this phaenomenon on a SCSI disc, too? 

I'd start by checking to see if the driver/hardware have negotiated the
same ATA DMA paramaters or not.  Specifically, what UDMA level (etc) was
negotiated).

Robert N M Watson