Subject: Re: ATI IXP IDE chipset support
To: Karl Janmar <karl@utopiafoundation.org>
From: Manuel Bouyer <bouyer@antioche.eu.org>
List: tech-kern
Date: 10/18/2004 23:58:47
On Mon, Oct 18, 2004 at 11:54:27PM +0200, Karl Janmar wrote:
> I did the read test with dd now, first making sure that the file wasn't in
> the cache.
> 
> # dd of=/dev/null if=apslaskr bs=4096 count=100000
> sync100000+0 records in
> 100000+0 records out
> 409600000 bytes transferred in 14.996 secs (27313950 bytes/sec)
> 
> I could also se on sysstat vmstat that I hade about 25M of disktransfer
> from wd0, as expected. So it seems that there is no problem to read/write
> to the blockdevice on my disk... but the character device....

This is strange, my test program does 64k reads, just as the block device does.
But my test program doens't do a sequential read, it always read the
same 64k over and over. Also it starts from sector 0.
Maybe this is the difference. Could you try a dd from the char device to
/dev/null with bs=64k ?

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