From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCH] mmc: core: Optimize boot time by detecting cards simultaneously Date: Fri, 18 Dec 2015 10:28:12 +0900 Message-ID: <5673612C.9050808@samsung.com> References: <1448982916-21485-1-git-send-email-ulf.hansson@linaro.org> <5670A0BA.8090402@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout2.samsung.com ([203.254.224.25]:51494 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965035AbbLRB2S (ORCPT ); Thu, 17 Dec 2015 20:28:18 -0500 Received: from epcpsbgr4.samsung.com (u144.gpu120.samsung.co.kr [203.254.230.144]) by mailout2.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NZJ00I895F4S480@mailout2.samsung.com> for linux-mmc@vger.kernel.org; Fri, 18 Dec 2015 10:28:16 +0900 (KST) In-reply-to: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson , Alan Cooper Cc: linux-mmc 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. >> >> 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 > >