From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konstantin Dorfman Subject: Re: [RFC PATCH 00/11] [FS, MM, block, MMC]: eMMC High Priority Interrupt Feature Date: Wed, 09 Jan 2013 10:15:39 +0200 Message-ID: <50ED272B.4000004@codeaurora.org> References: <1334730332-22244-1-git-send-email-svenkatr@ti.com> <3a028a6583c7fac372c8711930fc1874.squirrel@www.codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from wolverine02.qualcomm.com ([199.106.114.251]:64337 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756051Ab3AIIPn (ORCPT ); Wed, 9 Jan 2013 03:15:43 -0500 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Sergey Priporov Cc: linux-mmc@vger.kernel.org, Maya Erez Hello Sergey, I'm working on the same flow - to reduce read latency hit (as a result=20 of big aggregated writes). I plan to send all relevant patches to the=20 mailing list soon and it will be great if you can test them on your sys= tem. There are requirements for this flow is: - eMMC 4.5 supported by card (this means HPI) - host controller shoud implement stop request api (that is be able=20 correctly stop DMA & all internal state and be ready for next read=20 transaction. Right now, please look at this patches as reference: 1. [RFC/PATCH 0/2] Handling urgent and new request notifications. 2. [RFC/PATCH 1/2] mmc: Urgent data request flow. This is old changes, just for the solution overview. Thanks, > Hi Venkat, > > I was looking for some explanations of eMMC behavior in products we = are > developing now and found your comments around eMMC here. Our observat= ion > shows > that that eMMC performance vary significantly and depends on volume o= f > data to > write during time slot and temperature. After a heavy write test was = run > for > some time for a good performance eMMC (showing 10-12MB/s of the write > performance on big blocks) its write performance degraded to the 4-5M= B/s. > We even observed performance lowest level as 65KB/s! > There are a lot of Write type of operations necessary into dedicated = eMMC > partition by requirements. > The side effect is that long write operations block Application UI t= o > redraw > the views because it requires Read operations. > Visually we see =C3=A2=C2=80=C2=9CBlank Dark Screen=C3=A2=C2=80=C2=9D= for few seconds and even ANRs. So > HMI may > help us. > > Question: Did you finish research with HPI to try ? Which type of e= MMC > did > you use? > > P.S. We use TI BSP for OMAP3630 for Android > > > -- > 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 >