From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Lin Subject: Re: [PATCH] mmc: core: Optimize boot time by detecting cards simultaneously Date: Fri, 18 Dec 2015 11:05:23 +0800 Message-ID: <567377F3.2060906@rock-chips.com> References: <1448982916-21485-1-git-send-email-ulf.hansson@linaro.org> <5670A0BA.8090402@samsung.com> <5673612C.9050808@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from lucky1.263xmail.com ([211.157.147.132]:59500 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932906AbbLRDFo (ORCPT ); Thu, 17 Dec 2015 22:05:44 -0500 In-Reply-To: <5673612C.9050808@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Jaehoon Chung , Ulf Hansson , Alan Cooper Cc: shawn.lin@rock-chips.com, linux-mmc On 2015/12/18 9:28, Jaehoon Chung wrote: > Hi, > > On 12/18/2015 06:49 AM, Ulf Hansson wrote: >> On 17 December 2015 at 20:47, Alan Cooper wrote: >>> On Wed, Dec 16, 2015 at 4:07 AM, Ulf Hansson wrote: >>>> To find the improved card detection times, I just used the kernel boot >>>> log and checked the time stamps for when the cards get detected. I ran >>>> the tests ~10 times and picked up some average values. >>>> >>>> To notice the improvement you need at least two cards to be inserted >>>> during boot. Perhaps you have a platform with one eMMC and one SD card >>>> slot, you can test. >>> >>> I tested the patch on one of our ARM bases SoC's. The SoC has an SD >>> card slot on the first controller and an eMMC device on the second >>> controller. I found ~100ms improvement on the time it took for the >>> rootfs on the eMMC device to be ready for use. Interestingly, I did >>> see the SD/eMMC order swap once in 20 tries. This is not an issue for >>> us as we already have to use UUID for the eMMC rootfs in case an SD >>> card is installed. >>> hi Ulf, I'm interested in this patch since I also spent a little time optimzing the boot time and sequence for my local branch based on kernel 3.1x. With you patch, it seems, the tablet only achieves very small improvement for the SD controller(less than 20ms). My test environment: Kernel: 3.14 Slot: 1 emmc(1st) + 1 SD card(2nd) + 1 sdio card(3rd) I happen to run massive reboot test for my stable kernel branch this weekend, so I will apply this patch to see if any problem occurs. :) >>> Al >> >> Al, thanks for your effort in testing. I assume I can apply a >> tested-by tag for that! >> >> BTW, if you want to see an even better improvement, just find a >> crappier SD card as I guess you have a quite good one. :-) > > I didn't test with this yet..actually, i have tested with only one board(Exynos4412). > There is no the changing index. (Not too much for testing) > but in my experiment, our platform(Tizen) should be produced the problem in SD-card case. > I need to check with SystemFW guys. I will check this..ASAP. > > Best Regards, > Jaehoon Chung > >> >> Kind regards >> Uffe >> -- >> 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 >> >> > > -- > 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 > > > -- Best Regards Shawn Lin