On Wed, Jan 25, 2006 at 12:12:56PM +0100, Julio M. Merino Vidal wrote:
> Hi all,
> 
> I have a Maxtor 120GB drive currently installed on my workstation,
> an Athlon XP machine with a VIA KT400 chipset (thus using viaide(4)
> under NetBSD-current).  If I do the following to get a rough idea of
> the drive's performance:
> 
> 	dd if=/dev/wd0d of=/dev/zero bs=8m count=100
> 
> I get something around 22 MB/s.
> 
> The thing is that I would like to move that drive to my server and
> share it with Samba or whatever.  The server is a Pentium 3 450Mhz
> machine and has a PCI ATA100 controller.  I plugged the drive there
> and reran the same test as on the other machine.  It gave only
> 5 MB/s.
> 
> This machine is using cmdide(4) (on NetBSD 3.0) for that PCI card
> and the kernel reports that the drive is running in UDMA5 mode.
> 
> Might this be due to misconfiguration or, simply put, the machine
> cannot give more?
> 
> Thanks,
> 
> PS: Running the command shown above using rwd0d instead of wd0d on
> the P3 machine gives around 30MB/s.  (Haven't tried on the other
> box, though.)

Using the block device instead of raw device, all data go though the
buffer cache. Depending on what's your doing it may need to flush
other data first, and system CPU usage is much highter. If you get
30MB/s using the raw device your controller is fine.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--