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: Mon, 28 Dec 2015 17:44:48 +0800 Message-ID: <56810490.5020507@rock-chips.com> References: <1448982916-21485-1-git-send-email-ulf.hansson@linaro.org> <5670A0BA.8090402@samsung.com> <5673612C.9050808@samsung.com> <567377F3.2060906@rock-chips.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]:37387 "EHLO lucky1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750763AbbL1JpR (ORCPT ); Mon, 28 Dec 2015 04:45:17 -0500 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson Cc: shawn.lin@rock-chips.com, Jaehoon Chung , Alan Cooper , linux-mmc On 2015/12/28 17:31, Ulf Hansson wrote: > On 18 December 2015 at 04:05, Shawn Lin wrote: >> 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 Shawn, > > Thanks for helping out testing. > >> 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) > > How much time you *gain* comparing to the original behaviour for each > card, depends on the ->probe() order of your mmc hosts. > > I would guess that the host that holds the eMMC is the one being > probed first, right? > In general eMMC is quite fast to initialize, comparing to SD-cards and > that's probably the reason to why you don't see that much > improvements. > yes, my emmc is the first order to be probed. And sdio gain nearly 80ms with your patch. No any problems found yet. So I think this patch is good :) > Although, for your SDIO card you should see a greater improvement as > this don't need to wait for your SD and eMMC to be initialized. > >> >> 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. :) >> > > Great! > > As you haven't reported any problems, I suppose the tests went well!? > > 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 > > > -- Best Regards Shawn Lin