On 2015/12/28 17:31, Ulf Hansson wrote:
On 18 December 2015 at 04:05, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> 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 <alcooperx@xxxxxxxxx> wrote:
On Wed, Dec 16, 2015 at 4:07 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx>
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
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Best Regards
Shawn Lin
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