FreeBSD 5.3b7and poor ata performance

[Xin LI]

Hi, Mike

On Tue, Oct 19, 2004 at 04:18:12PM -0400, Mike Jakubik wrote:
> Xin LI said:
> 
> > Unfortunatelly I can reproduce similiar problem when using Ultra320 under
> > mpt(4) and a version of Adaptec's SCSI card (maybe aic, or something else,
> > which I have to go to my office to find out).  Additionally the problem is
> > not FreeBSD specific, with a Linux installation, it shows poor performance
> > too.  (No RAID configuration, though).
> >
> > I found that block size does influence performance greatly.  With a block
> > size of 131072 I got peak read performance at about 70MB/s, but that's
> > all.
> > I did not have the necessary knowledge at the time I have did the test
> > last
> > month, so I got only the result and thought that I have made something
> > wrong and hoped someone to correct me with no luck :-(
> 
> Hrm, i tried your block size, and the performance is even worse:
> 
> # dd if=/dev/da0 of=/dev/null bs=131072 count=2000
> 2000+0 records in
> 2000+0 records out
> 262144000 bytes transferred in 8.688651 secs (30170852 bytes/sec)

You may want to try other block sizes, like 65536, 262144, 524288, 1048576
or so.  The peak performance block size depends heavily on hardware...

Cheers,
-- 
Xin LI <delphij frontfree net>	http://www.delphij.net/
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