From: Tejun Heo <htejun@gmail.com>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: Why is NCQ enabled by default by libata? (2.6.20)
Date: Tue, 27 Mar 2007 19:10:17 +0900 [thread overview]
Message-ID: <4608ED89.5040407@gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0703270554320.31853@p34.internal.lan>
Justin Piszcz wrote:
> 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.
Are they testing using Linux? I/O performance is highly dependent on
workload and scheduling, so result on windows wouldn't be very useful.
Posting some links here would be nice.
> I see 30-50MB/s faster speeds with NCQ turned off on two
> different SW RAID5s.
You're testing raptors, right? If the performance drop is that drastic
and consistent over different workloads, we'll have to disable NCQ for
raptors. I'm not sure about other drives. Care to perform tests over
more popular ones (e.g. recent seagates or 7200rpm wds)?
--
tejun
next prev parent reply other threads:[~2007-03-27 10:10 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-24 16:38 Why is NCQ enabled by default by libata? (2.6.20) Justin Piszcz
2007-03-24 18:43 ` Alan Cox
2007-03-27 9:55 ` Justin Piszcz
2007-03-27 10:10 ` Tejun Heo [this message]
2007-03-27 10:30 ` Justin Piszcz
2007-03-27 5:59 ` Jeff Garzik
2007-03-27 14:26 ` Mark Lord
2007-03-27 18:18 ` Mark Rustad
2007-03-27 18:38 ` Jeff Garzik
2007-03-27 22:12 ` Mark Rustad
2007-03-31 12:55 ` Ric Wheeler
[not found] <fa.MhN9pBMjZID4rnTNn+fU01uZiss@ifi.uio.no>
2007-03-24 22:11 ` Robert Hancock
-- strict thread matches above, loose matches on Subject: below --
2007-03-27 16:16 linux
2007-03-27 16:25 ` Justin Piszcz
2007-03-27 16:41 ` linux
2007-03-27 16:44 ` Justin Piszcz
2007-03-27 16:58 ` linux
2007-03-27 17:03 ` Justin Piszcz
2007-03-28 14:42 ` Phillip Susi
2007-03-28 14:48 ` Jeff Garzik
2007-03-29 17:28 ` Phillip Susi
2007-03-29 18:40 ` linux
2007-03-29 18:51 ` Jeff Garzik
2007-03-29 21:35 ` Alan Cox
2007-03-29 21:47 ` David Schwartz
2007-03-30 16:33 ` Lennart Sorensen
[not found] <fa.NmF2xJwO4BeVbJrFRkf7oV9EYmQ@ifi.uio.no>
[not found] ` <fa.39luedDWsoqip+QMNtfAv8jvyNg@ifi.uio.no>
[not found] ` <fa.b1cZfpMNhZ0teK/UauKLDWw60Jc@ifi.uio.no>
[not found] ` <fa.xWaBy6HZTRTgI+PxinV8ajuOlJI@ifi.uio.no>
[not found] ` <fa.BiSx71HKysC9QIpS8DLip5BmfxI@ifi.uio.no>
2007-04-01 17:28 ` Robert Hancock
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