From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Ball Subject: Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5 Date: Tue, 10 Jul 2012 03:33:55 -0400 Message-ID: <87mx38qdcs.fsf@octavius.laptop.org> References: <006801cd55b0$314960f0$93dc22d0$%jun@samsung.com> <87y5msqhxy.fsf@octavius.laptop.org> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from void.printf.net ([89.145.121.20]:50054 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751174Ab2GJHeD (ORCPT ); Tue, 10 Jul 2012 03:34:03 -0400 In-Reply-To: (merez@codeaurora.org's message of "Mon, 9 Jul 2012 23:23:52 -0700 (PDT)") Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: merez@codeaurora.org Cc: Seungwon Jeon , linux-mmc@vger.kernel.org, 'Subhash Jadavani' , "'S, Venkatraman'" , 'Saugata Das' , 'Namjae Jeon' Hi, On Tue, Jul 10 2012, merez@codeaurora.org wrote: >> Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN >> a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was? > > No, it's not. Excellent, thanks. I've pushed both v8 patches to mmc-next. Before pushing it up to Linus, I'd like to get a better idea of the variety of performances differences seen using packed writes -- has it been tried on devices from multiple eMMC vendors, and multiple host controller vendors? Can we try to build up a quick table of results, with a standard test like iozone, to check that we've got decent test coverage? Seungwon suggests using: iozone -az -i0 -I -s 10m -f /target/test -e I'm also worried about how much code this is adding, but I agree that it's worth it if the performance benefits are as described. Thanks, - Chris. -- Chris Ball One Laptop Per Child