From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759139Ab2CMArN (ORCPT ); Mon, 12 Mar 2012 20:47:13 -0400 Received: from mailout3.samsung.com ([203.254.224.33]:35535 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753711Ab2CMArI convert rfc822-to-8bit (ORCPT ); Mon, 12 Mar 2012 20:47:08 -0400 X-AuditID: cbfee61b-b7c62ae000000989-81-4f5e990ad625 From: Seungwon Jeon To: merez@codeaurora.org Cc: "'Namjae Jeon'" , linux-mmc@vger.kernel.org, "'Chris Ball'" , linux-kernel@vger.kernel.org References: <4934441a17d25c3249556f7bf281b1be.squirrel@www.codeaurora.org> <6669559e86c1d13b27e941ff2acf89d2.squirrel@www.codeaurora.org> <000001ccfbf7$ac3e7510$04bb5f30$%jun@samsung.com> In-reply-to: Subject: RE: [PATCH v5 2/2] mmc: core: Support packed command for eMMC4.5 device Date: Tue, 13 Mar 2012 09:47:05 +0900 Message-id: <000301cd00b2$d08a84d0$719f8e70$%jun@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=Windows-1252 Content-transfer-encoding: 8BIT X-Mailer: Microsoft Office Outlook 12.0 Thread-index: Acz/zxVxQ2M0Rg66SZ24XooUL6b1+QAESzUA Content-language: ko X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Maya Erez wrote: > > Maya Erez wrote: > >> > Hi. Merez. > >> > > >> > Thanks a lot about your performance measurement. > >> > > >> > I think that your measurement is enough and correct and the firmware > >> > of mmc vender should be optimized or change properly rather than > >> > modifying the current patch. > >> > > >> > And currently we can use only write packed cmd by my suggestion. > >> > > >> > I would like to add my reviewd-by tag in updated patches also. > >> > > >> > Reviewed-by: Namjae Jeon > >> > > >> > Thanks. > >> > >> I tend to disagree. Adding a massive amount of code that would be > >> disabled > >> can be risky. In case this code will not be in use it will not be > >> properly > >> tested and its reliability will be uncertain. > >> > > If you found something to be correct, please let me know that. > > It would be rightly appreciated. > > > > Best regards, > > Seungwon Jeon. > Hi Jeon, > > The write packing code looks good to me. > However, the separation of read and write packing to different patches is > very important to us. > As I specified before, we decided to enable only the write packing. We > plan to thoroughly test the write packing (edge cases and error handling) > and will not test the read packing. Therefore we would like to have the > ability to get only the write packing code. As Namjae Jeon mentioned, how about this? I think only MMC_CAP2_PACKED_WR can be set for enabling the write packing easily. In my case, tested eMMC device is not optimized for packed read. So I couldn't confirm that this patch is effective in packed read. I think packed read as well as packed write of this patch conformed with the eMMC4.5 spec though. I wonder that your eMMC device has the good ability in both operations. It is difficult to decide the performance with excluding the device. Soon I will test it with the improved sample for packed read. > In my previous comment I talked about the risk of mainlining a “dead” > code. Every feature that is integrated is considered to be fully tested > and in the future it might be enabled, assuming that is was already > tested. Right! It is desirable and I hope that. Do you think this patch have the potential problem? As I also ask you, if you have tested and find something is incorrect, we can discuss that. It was submitted for that purpose. > Can you please specify how you tested the read and write packing? Did you > perform edge cases and error handling tests? Do you have test code that > can be shared? Basically, It has been tested with several I/O benchmark tool. Some misvalued I/O timing and wrong argument for packed command was used for triggering the error case. Best regards, Seungwon Jeon. > > Thanks, > Maya Erez > Consultant for Qualcomm Innovation Center, Inc. > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html