FreeBSD 5.3b7and poor ata performance

[Kris Kennaway]

On Thu, Oct 21, 2004 at 09:35:12AM +0200, fandino wrote:
> Mike Tancsa wrote:
> >Its strange that you do not see any difference in speed when reading 
> >from the device directly vs a file ? I see quite a difference in my 
> >setup on a RELENG_5 box and not so much a difference on a RELENG_4 box.  
> >Perhaps as someone suggested, the GEOM layer ?
> >
> >e.g. create a file with junk larger than your RAM. (the machine below 
> >has 256M)
> 
> -- same mobo and same disks --
> 
> OpenBSD 3.5:
> 
> dd if=/mnt/aa of=/dev/null bs=1024k count=1024
> 1024+0 records in
> 1024+0 records out
> 1073741824 bytes transferred in 18.743 secs (57287584 bytes/sec)
> 
> 
> FreeBSD 5.3rc1:
> 
> # dd if=/mnt/aa of=/dev/null bs=1024k count=1024
> 1024+0 records in
> 1024+0 records out
> 1073741824 bytes transferred in 42.215597 secs (25434719 bytes/sec)

BTW, others have asked that you not use dd as your "benchmark",
because it's not benchmarking anything relevant for real-world use of
the disk.

Kris
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