Messages in this thread |  | | | Date | Tue, 27 Mar 2007 05:55:44 -0400 (EDT) | | From | Justin Piszcz <> | | Subject | Re: Why is NCQ enabled by default by libata? (2.6.20) |
| |
On Sat, 24 Mar 2007, Alan Cox wrote:
> On Sat, 24 Mar 2007 12:38:02 -0400 (EDT) > Justin Piszcz <jpiszcz@lucidpixels.com> wrote: > >> Without NCQ, performance is MUCH better on almost every operation, with >> the exception of 2-3 items. > > It depends on the drive. Generally NCQ is better but some drive firmware > isn't too bright and there are probably still cases where we get bad > interactions in the kernel code that want tuning too >
Checking the benchmarks on various hardware websites, anandtech, hothardware and others, they generally all come to the same conclusion if there is only 1 thread using I/O (single user system) then NCQ off is the best. I see 30-50MB/s faster speeds with NCQ turned off on two different SW RAID5s.
Justin. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |