From owner-freebsd-current@FreeBSD.ORG Tue Dec 15 09:36:28 2009 Return-Path: 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 3A68D106566B; Tue, 15 Dec 2009 09:36:28 +0000 (UTC) (envelope-from barnaclewes@gmail.com) Received: from mail-qy0-f176.google.com (mail-qy0-f176.google.com [209.85.221.176]) by mx1.freebsd.org (Postfix) with ESMTP id C403B8FC13; Tue, 15 Dec 2009 09:36:27 +0000 (UTC) Received: by qyk6 with SMTP id 6so1918398qyk.3 for ; Tue, 15 Dec 2009 01:36:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=VRQ5hyA4Mei9xR4n/Ro5APA/rjty8s96Wudr4XlfkJM=; b=vldV7kt0eFJ4YNGoCPtUzNVcOJNpU2neGaRZhIwrdg0EcsHJai90O//i3SP8C7TKTF M2dwg8tRfjZoeOPF373+kQoa+Mt8UXIuowwEAviYUDXWs/lJ5cTO32MhoaWOk76kqmki DcdnDvrrqBV3he9R0C3Jpm1ge11b26qDK2qPc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=j+mjw6JTf1NZro6TGxvteJEIfZ91ZShxHuHefaIDRWU1JUBaGCiCrbLxYS15wZP/Co ipC+SURCpa6RqTCKPl00CKvCZNOxVX2krswC0OiISPT5SztiHi/NsZ4V9X0JsnQp1kit D+HunXbKkxiodGEvW8lraLZb32n/a5ZkLEbmk= MIME-Version: 1.0 Received: by 10.224.112.5 with SMTP id u5mr3718422qap.362.1260869787033; Tue, 15 Dec 2009 01:36:27 -0800 (PST) In-Reply-To: <20091119004651.7432a6e4.nork@FreeBSD.org> References: <20091119004651.7432a6e4.nork@FreeBSD.org> Date: Tue, 15 Dec 2009 01:36:27 -0800 Message-ID: From: Wes Peters To: Norikatsu Shigemura Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Alexander Motin , freebsd-current@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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Dec 2009 09:36:28 -0000 On Wed, Nov 18, 2009 at 7:46 AM, Norikatsu Shigemura wro= te: > Hi Alexander! > > =A0 =A0 =A0 =A0I have a Intel 64GB SSD(X25-E) and a Western Digital Cavia= r Green > =A0 =A0 =A0 =A01TB HDD (WD10EADS), and use them on ahci(4). =A0ahci(4) ca= n use NCQ > =A0 =A0 =A0 =A0of WD10EADS, but doesn't use NCQ of X25-E. How useful is NCQ on an SSD? Isn't the primary thrust of NCQ to allow the disk to reorder writes to optimize the seek pattern? --=20 Against stupidity the very gods Themselves contend in vain. Friedrich Schiller