From owner-freebsd-current@FreeBSD.ORG  Wed Dec 16 13:14:08 2009
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id ABAEE1065672;
	Wed, 16 Dec 2009 13:14:08 +0000 (UTC) (envelope-from des@des.no)
Received: from tim.des.no (tim.des.no [194.63.250.121])
	by mx1.freebsd.org (Postfix) with ESMTP id 60D948FC1C;
	Wed, 16 Dec 2009 13:14:08 +0000 (UTC)
Received: from ds4.des.no (des.no [84.49.246.2])
	by smtp.des.no (Postfix) with ESMTP id 665C66D41B;
	Wed, 16 Dec 2009 13:14:07 +0000 (UTC)
Received: by ds4.des.no (Postfix, from userid 1001)
	id F0613844F3; Wed, 16 Dec 2009 14:14:06 +0100 (CET)
From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To: Wes Peters <barnaclewes@gmail.com>
References: <20091119004651.7432a6e4.nork@FreeBSD.org>
	<f83770800912150136u1fbabd2ak7b0cd15f85c0099f@mail.gmail.com>
Date: Wed, 16 Dec 2009 14:14:06 +0100
In-Reply-To: <f83770800912150136u1fbabd2ak7b0cd15f85c0099f@mail.gmail.com>
	(Wes Peters's message of "Tue, 15 Dec 2009 01:36:27 -0800")
Message-ID: <86zl5jjc2p.fsf@ds4.des.no>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.95 (berkeley-unix)
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Cc: Alexander Motin <mav@freebsd.org>, freebsd-current@freebsd.org,
	Norikatsu Shigemura <nork@freebsd.org>
Subject: Re: How do I use NCQ of Intel X25-E(SSD) on ahci(4)?
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
	<mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
	<mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 16 Dec 2009 13:14:08 -0000

Wes Peters <barnaclewes@gmail.com> writes:
> How useful is NCQ on an SSD?

*extremely* useful.  The X25 is old (as SSDs go), yet it still blows the
competition out of the water on real-world (non-sequential) workloads,
precisely because it supports NCQ and most of its competitors don't.

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no