From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: Linux 2.6.29 Date: Tue, 31 Mar 2009 18:22:15 -0400 Message-ID: <49D29797.80200@garzik.org> References: <20090324093245.GA22483@elte.hu> <20090324101011.6555a0b9@lxorguk.ukuu.org.uk> <20090324103111.GA26691@elte.hu> <20090324132032.GK5814@mit.edu> <20090324184549.GE32307@mit.edu> <49C93AB0.6070300@garzik.org> <20090325093913.GJ27476@kernel.dk> <49CA86BD.6060205@garzik.org> <20090325194341.GB27476@kernel.dk> <49D281D8.8030203@garzik.org> <49D2930A.5030905@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:55603 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757562AbZCaWXM (ORCPT ); Tue, 31 Mar 2009 18:23:12 -0400 In-Reply-To: <49D2930A.5030905@redhat.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Ric Wheeler Cc: Jens Axboe , Linus Torvalds , Theodore Tso , Ingo Molnar , Alan Cox , Arjan van de Ven , Andrew Morton , Mark Lord , Linux Kernel Mailing List , Linux IDE mailing list Ric Wheeler wrote: > Jeff Garzik wrote: >> Jens Axboe wrote: >>> Another problem is that FLUSH_CACHE sucks. Really. And not just on >>> ext3/ordered, generally. Write a 50 byte file, fsync, flush cache and >>> wit for the world to finish. Pretty hard to teach people to use a nicer >>> fdatasync(), when the majority of the cost now becomes flushing the >>> cache of that 1TB drive you happen to have 8 partitions on. Good luck >>> with that. >> >> (responding to an email way back near the start of the thread) >> >> I emailed Microsoft about their proposal to add a WRITE BARRIER >> command to ATA, documented at >> http://www.t13.org/Documents/UploadedDocuments/docs2007/e07174r0-Write_Barrier_Command_Proposal.doc >> The MSFT engineer said they were definitely still pursuing this proposal. >> >> IMO we could look at this too, or perhaps come up with an alternate >> proposal like FLUSH CACHE RANGE(s). > I agree that it is worth getting better mechanisms in place - the cache > flush is really primitive. Now we just need a victim to sit in on > T13/T10 standards meetings :-) Heck, we could even do a prototype implementation with the help of Mark Lord's sata_mv target mode support... Jeff