From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] speed up SATA Date: Sun, 28 Mar 2004 12:54:21 -0500 Sender: linux-ide-owner@vger.kernel.org Message-ID: <4067114D.7050606@pobox.com> References: <4066021A.20308@pobox.com> <40661049.1050004@yahoo.com.au> <406611CA.3050804@pobox.com> <406616EE.80301@pobox.com> <4066191E.4040702@yahoo.com.au> <40662108.40705@pobox.com> <20040328135124.GA32597@mail.shareable.org> <40670A36.3000005@pobox.com> <20040328173623.GA1087@mail.shareable.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:27861 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262130AbUC1Rye (ORCPT ); Sun, 28 Mar 2004 12:54:34 -0500 In-Reply-To: <20040328173623.GA1087@mail.shareable.org> List-Id: linux-ide@vger.kernel.org To: Jamie Lokier Cc: Nick Piggin , linux-ide@vger.kernel.org, Linux Kernel , Andrew Morton Jamie Lokier wrote: > This is what I mean: turn off write cacheing, and performance on PATA > drops because of the serialisation and lost inter-command time. > > With TCQ-on-write, you can turn off write cacheing and in theory > performance doesn't have to drop, is that right? hmmm, that's a good point. I honestly don't know. Something to be tested, I suppose... My premature guess would be that you would need a queue depth larger than 2 or 4 before performance starts to not-suck. Jeff