From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [[v4] 2/5] MMC: Use CMD23 for multiblock transfers when we can. Date: Fri, 20 May 2011 18:05:41 +0900 Message-ID: <4DD62EE5.8040604@samsung.com> 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 Content-Transfer-Encoding: 7BIT Return-path: Received: from mailout2.samsung.com ([203.254.224.25]:15918 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934436Ab1ETJFr (ORCPT ); Fri, 20 May 2011 05:05:47 -0400 Received: from epcpsbgm2.samsung.com (mailout2.samsung.com [203.254.224.25]) by mailout2.samsung.com (Oracle Communications Messaging Exchange Server 7u4-19.01 64bit (built Sep 7 2010)) with ESMTP id <0LLH004OML98GCH0@mailout2.samsung.com> for linux-mmc@vger.kernel.org; Fri, 20 May 2011 18:05:45 +0900 (KST) Received: from TNRNDGASPAPP1.tn.corp.samsungelectronics.net ([165.213.149.150]) by mmp1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0LLH0042SL9KJB@mmp1.samsung.com> for linux-mmc@vger.kernel.org; Fri, 20 May 2011 18:05:44 +0900 (KST) In-reply-to: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Andrei Warkentin Cc: Jaehoon Chung , linux-mmc@vger.kernel.org, arindam.nath@amd.com, cjb@laptop.org, arnd@arndb.de, Kyungmin Park , "Gao, Yunpeng" Andrei Warkentin wrote: > 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. > I used two host-controller (sdhci and dw_mmc). you implemented them in sdhci. I applied your patch then tested CMD23...but i didn't applied auto-CMD23. I known that auto-CMD23 supported at SD3.0..right? My controller is supported SD2.0.. If you can consult me, too much helpful to me.. Regards, Jaehoon Chung