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IMX6 uSDHC controller performance

Question asked by edison xu on Dec 31, 2015
Latest reply on Feb 13, 2016 by Martin Ma

HI Community,

     I'm testing the uSDHC controller performance on IMX6S demo board

Kernel: 3.10.17

SD card: Transcent 16GB UHS-I 600X TF (max read/write speed 90MB/s)

SD card reader: support USB 3.0

 

1 Using uSDHC controller

dd if=/dev/mmcblk1 of=/dev/null bs=4096k count=100

100+0 records in

100+0 records out

419430400 bytes (400.0MB) copied, 20.196583 seconds, 19.8MB/s

     The performance is very poor, even lower than 20MB/s, it is far from the speed on the reference manual - Up to 104MB/s

 

2 Using USB card reader

dd if=/dev/sda of=/dev/null bs=4096k count=100

100+0 records in

100+0 records out

419430400 bytes (400.0MB) copied, 15.732688 seconds, 25.4MB/s

     The IMX6S only support USB2.0 host, so it cannot get the maximum speed, however, the performance is better than uSDHC controller.

     Can IMX expert give explanation on this difference? How to get the best performance of uSDHC controller?         

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