Re: Playing with SATA NCQ

Jeff Garzik
2005-05-29T19:05:48Z

On Sun, May 29, 2005 at 09:04:21PM +0200, Jens Axboe wrote:
> On Sun, May 29 2005, Mark Lord wrote:
> > My basic hdparm timing test shouldn't show much of a difference
> > with NCQ tests, becase hdparm just does a single request at a time,
> > and waits for the results before issuing another. Now, kernel read-ahead
> > may result in some command overlap and a slight throughput increase, but..
> >
> > Something like dbench and/or bonnie++ are more appropriate here.
>
> I don't like bonnie++ very much and dbench is very write intensive. I
> would suggest trying tiotest, find it on sf.net. It gets easily readable
> results and they are usually fairly consistent across runs if you limit
> the RAM to something sensible (eg 256MB and using a data set size of
> 768MB).

As an FYI... download Stephen Tweedie's verify-data tool at
http://people.redhat.com/sct/src/verify-data/

Robin Miller's 'dt' is also nice to have.

Jeff