From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262446AbTLBRk4 (ORCPT ); Tue, 2 Dec 2003 12:40:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262603AbTLBRk4 (ORCPT ); Tue, 2 Dec 2003 12:40:56 -0500 Received: from adsl-63-194-239-202.dsl.lsan03.pacbell.net ([63.194.239.202]:39179 "EHLO mmp-linux.matchmail.com") by vger.kernel.org with ESMTP id S262446AbTLBRky (ORCPT ); Tue, 2 Dec 2003 12:40:54 -0500 Date: Tue, 2 Dec 2003 09:40:48 -0800 From: Mike Fedyk To: Greg Stark Cc: Erik Steffl , linux-kernel@vger.kernel.org Subject: Re: libata in 2.4.24? Message-ID: <20031202174048.GQ1566@mis-mike-wstn.matchmail.com> Mail-Followup-To: Greg Stark , Erik Steffl , linux-kernel@vger.kernel.org References: <3FCB8312.3050703@rackable.com> <87fzg4ckej.fsf@stark.dyndns.tv> <3FCBB15F.7050505@rackable.com> <3FCBB9F1.2080300@bigfoot.com> <87n0abbx2k.fsf@stark.dyndns.tv> <20031202055336.GO1566@mis-mike-wstn.matchmail.com> <20031202055852.GP1566@mis-mike-wstn.matchmail.com> <87zneb9o5q.fsf@stark.dyndns.tv> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87zneb9o5q.fsf@stark.dyndns.tv> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 02, 2003 at 11:31:45AM -0500, Greg Stark wrote: > > Mike Fedyk writes: > > > > Libata, uses the scsi system instead of the existing ide layer because many > > > new sata controllers are using an interface that is very similair to scsi > > > (much like atapi). > > Now I have a different question. Does the scsi-like SATA interface include tcq? > > Because one of the long-standing issues with IDE drives and Postgres is the > fact that even after issuing an fsync the data may be sitting in the drive's > buffer. This doesn't happen with SCSI because the drives aren't forced to lie > about the data being on disk in order to handle subsequent requests. Turning > off write-caching on IDE drives absolutely destroys performance. There are PATA drives that do TCQ too, but you have to look for that feature specifically. IDE TCQ is in 2.6, but is still experemental. I think Jens Axboe was the one working on it IIRC. He would have more details. > > Do the new SATA drives and controllers provide a solution to this? It's not SATA specific, and I'm not sure if any ide controller can support TCQ or if only a specific list are compatible. Mike