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eMMC on iMX6 high latency

Question asked by Einar Bjorgvinsson on Sep 22, 2015
Latest reply on Sep 24, 2015 by Einar Bjorgvinsson

I have a MTFC8GLDDQ-4M eMMC NAND flash from Micron and a custom made board with iMX6Q on it.

My system setup is as following:

 

kernel: 3.10.17 (RT patched) minor boot customization for our board

uboot: 2014

rootfs: in-house (hard compiled) 

toolchain: Linaro gcc 4.7.2

 

The system is working fine except the high latency in disk I/O, running the command sync can sometime take 4-5 seconds.

I have tried to backport the mmc driver from kernel 4.2 without any success.

I have also tried various RT settings for the mmc/jbd kernel threads and played around with the dirty_ratio and other settings in /proc/sys/vm without any major difference.

 

Before I go and dive into the driver I liked to ask if this is a known problem or not ?

 

kind regards

Einar

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