From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Bolkhovitin Subject: Re: [sqlite] light weight write barriers Date: Mon, 12 Nov 2012 22:42:25 -0500 Message-ID: <50A1C1A1.7060200@vlnb.net> References: <5086F5A7.9090406@vlnb.net> <20121025051445.GA9860@thunk.org> <508B3EED.2080003@vlnb.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Theodore Ts'o , General Discussion of SQLite Database , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Richard Hipp To: =?UTF-8?B?5p2o6IuP56uLIFlhbmcgU3UgTGk=?= Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org =E6=9D=A8=E8=8B=8F=E7=AB=8B Yang Su Li, on 11/10/2012 11:25 PM wrote: >> SATA's Native Command >>> Queuing (NCQ) is not equivalent; this allows the drive to reorder >>> requests (in particular read requests) so they can be serviced more >>> efficiently, but it does *not* allow the OS to specify a partial, >>> relative ordering of requests. >>> >> >> And so? If SATA can't do it, does it mean that nobody else can't do = it >> too? I know a plenty of non-SATA devices, which can do the ordering >> requirements you need. >> > > I would be very much interested in what kind of device support this k= ind of > "topological order", and in what settings they are typically used. > > Does modern flash/SSD (esp. which are used on smartphones) support th= is? > > If you could point me to some information about this, that would be v= ery > much appreciated. I don't think storage in smartphone can support such advanced functiona= lity,=20 because it tends to be the cheapest, hence the simplest. But many modern Enterprise SAS drives can do it, because for those cust= omers=20 performance is the key requirement. Unfortunately, I'm not sure I can n= ame exact=20 brands and models, because I had my knowledge from NDA'ed docs, so this= info can=20 be also NDA'ed. Vlad