From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrei Warkentin Subject: Re: [[v4] 2/5] MMC: Use CMD23 for multiblock transfers when we can. Date: Fri, 20 May 2011 01:54:26 -0500 Message-ID: References: <1302950458-1969-1-git-send-email-andreiw@motorola.com> <1303870235-29041-1-git-send-email-andreiw@motorola.com> <1303870235-29041-2-git-send-email-andreiw@motorola.com> <1303870235-29041-3-git-send-email-andreiw@motorola.com> <4DD48273.4060402@samsung.com> <4DD5F045.90001@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from exprod5og111.obsmtp.com ([64.18.0.22]:43079 "EHLO exprod5og111.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933731Ab1ETGy2 (ORCPT ); Fri, 20 May 2011 02:54:28 -0400 Received: from DE01MGRG01.AM.MOT-MOBILITY.COM ([10.176.130.20]) by DE01MGRG01.AM.MOT-MOBILITY.COM (8.14.3/8.14.3) with ESMTP id p4K6swPK011708 for ; Fri, 20 May 2011 02:54:58 -0400 (EDT) Received: from mail-ww0-f46.google.com (mail-ww0-f46.google.com [74.125.82.46]) by DE01MGRG01.AM.MOT-MOBILITY.COM (8.14.3/8.14.3) with ESMTP id p4K6sXDC011598 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=OK) for ; Fri, 20 May 2011 02:54:58 -0400 (EDT) Received: by mail-ww0-f46.google.com with SMTP id 28so3591719wwb.3 for ; Thu, 19 May 2011 23:54:26 -0700 (PDT) In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Jaehoon Chung Cc: linux-mmc@vger.kernel.org, arindam.nath@amd.com, cjb@laptop.org, arnd@arndb.de, Kyungmin Park , "Gao, Yunpeng" On Fri, May 20, 2011 at 1:49 AM, Andrei Warkentin wrote: > On Thu, May 19, 2011 at 11:38 PM, Jaehoon Chung wrote: >> Hi Andrei, >> >> Andrei Warkentin wrote: >>> On Wed, May 18, 2011 at 9:37 PM, Jaehoon Chung wrote: >>>> Hi Andrei >>>> >>>> Andrei Warkentin wrote: >>>>> CMD23-prefixed instead of open-ended multiblock transfers >>>>> have a performance advantage on some MMC cards. >>>>> >>>> you mentioned about "some MMC cards". >>>> Conversely, that means the some card didn't have a performance advantage? >>>> >>>> Did you find the performance advantage? >>>> if you found the advantage and you can tell me, >>>> i want to know what do you have the some MMC cards.. >>>> >>> >>> I've tested this on a Sandisk eMMC where I saw as good as >>> a 50% improvement on writes (30% real-life use cases). This was a >>> SEM32G 4.3+ part. >> >> Can you tell me your environment? buswidth, AP information, benchmark etc.. >> And if you have the performance result's data, can you share them? >> > > This was on an SDHCI controller (hence the patch...) on a Tegra > 2-based system. I was measuring > throughput on reads and writes (obviously without block cache, > filesystem, etc) to an eMMC card, 8 bits. > > Tested both with my tool (https://github.com/andreiw/superalign) and > an sqllite-based test. > > I'm attaching the data I have. > > A > Additionally, CMD23 use is a requirement for SDXC cards (Arindam can comment on that), as well as for MMC reliable writes and eMMC 4.5-spec features (Yunpeng Gao can comment on that). These patches allow CMD23 use. They do involve a some changes to host controller because of interaction with CMD12, as well as Auto-CMD12 and Auto-CMD23 features. I can definitely consult you if you need help implementing CMD23 support for whatever controller you develop for. A