LinuxQuestions.org - zynq7020 usb2.0 in mass storage device mode with emmc,and it's speed is too slow

version of kernel: 4.4.0-xilinx

Hi guys,
I have followed https://xilinx-wiki.atlassian.net/wi...+Device+Driver to config zynq7020 usb2.0 as mass storage device,it worked.

The problem is:

If i use SDRAM as storage media(which means i use dd if=/dev/zero of=/tmp/mydev count=200 bs=1M),the speed of PC send file to zynq is about 27MB/s.

But if i use emmc as storage media(which means i use dd if=/dev/zero of=/home/root/mydev count=200 bs=1M),the speed of PC send file to zynq is only about 500KB/s.

What have i tried:
I used iozone to test emmc's read and write performance,below it's result(write speed is about 9MB/s,read speed is about 20MB/s):

Quote:

./iozone -a -n 512M -g 1G -i 0 -i 1 -i 5 -f /mnt/data/iozone -Rb ./iozone.xls

The top row is records sizes, the left column is file sizes
Writer Report
4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384
524288 0 0 0 0 9695 9508 9758 9546 9365 9651 9770 9511 9299
1048576 0 0 0 0 9132 9054 9110 9035 8826 9206 8903 9261 8837
Re-writer Report
4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384
524288 0 0 0 0 9729 9863 9820 9766 9697 9614 9906 9661 9541
1048576 0 0 0 0 9263 9054 9131 8997 8933 9315 8986 9166 9058
Reader Report
4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384
524288 0 0 0 0 19682 19809 19871 19824 19534 19915 19983 19781 20078
1048576 0 0 0 0 19662 19954 19775 19982 19823 19845 20067 20129 20270
Re-reader Report
4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384
524288 0 0 0 0 20102 20110 20128 20112 20121 20198 20219 20353 20704
1048576 0 0 0 0 20140 20132 20135 20137 20155 20169 20204 20277 20441
Stride Read Report
4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384
524288 0 0 0 0 25346 31185 32514 33926 34923 34402 33168 30944 31275
1048576 0 0 0 0 18271 18272 20404 21027 21280 21323 21223 21556 21400

so the emmc's driver is correct.

Is usb's driver something wrong?I'm not family with linux usb's framework.How can i fix this issue?

Thanks.