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: Mon, 23 May 2011 14:33:00 -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> <4DDA55B6.3040708@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from exprod5og116.obsmtp.com ([64.18.0.147]:42520 "EHLO exprod5og116.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933483Ab1EWTdD (ORCPT ); Mon, 23 May 2011 15:33:03 -0400 Received: from DE01MGRG01.AM.MOT-MOBILITY.COM ([10.22.94.168]) by DE01MGRG01.AM.MOT-MOBILITY.COM (8.14.3/8.14.3) with ESMTP id p4NJXX8w024026 for ; Mon, 23 May 2011 15:33:34 -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 p4NJSeak022257 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=OK) for ; Mon, 23 May 2011 15:33:33 -0400 (EDT) Received: by mail-ww0-f46.google.com with SMTP id 28so6383773wwb.3 for ; Mon, 23 May 2011 12:33:01 -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 Mon, May 23, 2011 at 2:25 PM, Andrei Warkentin wrote: > On Mon, May 23, 2011 at 7:40 AM, Jaehoon Chung wrote: >> Hi A.. >> >> I tested your patch..(using CMD23) >> my environment is the below. >> eMMC card : Sandisk SEM8G (eMMC 4.3+) >> buswidth : 4bit (SDR) >> AP : C110 >> benchmark : IOzone >> >> I want to know how do you think about this result? >> (i can't see your results) >> > > I think that you should use my tool to measure I/O performance. > Because I want to see the mins, maxes, average and > std dev. Iozone adds way too much noise to the data. You can run it 5 > times in a row and get completely different numbers. Please use > https://github.com/andreiw/superalign. > > For a more realistic test you can try performing 20000 sqlite inserts > or something of the sort and timing that. > > A > Additionally, be careful how you do your testing. I don't want to sound obvious, but, to ensure you can actually compare the collected data against each other - 1) Disable all power/frequency scaling/management/gating, suspend/resume, etc. 2) Make sure nothing else uses the eMMC. No root mounted fs, nothing. 3) Make sure you are avoiding block cache and file system. You want direct block I/O. 4) For extra extra extra reliable results - Make sure you are not rebooting across testing. You will need to add a flag so you can disable CMD23 on the fly via debugfs. For sqlite testing some other helpful hints - 1) Unmount partition containing files on which the SQLite test operates. 2) Perform BLKDISCARD over the partition. 3) Format with desired file system. 4) Mount. 6) Sync && echo 3 > /proc/sys/vm/drop_caches 7) Perform test. 8) Umount. 9) Repeat from (1) A