MMC/SD Card and USB Throughput¶

Testing was performed on a 3354-HX-X38-RC module in a devkit rev. 3A, running the filesystem from the mitysom-335x-devkit-MDK-2017-03-06.sh Yocto based MDK.
The real speeds were calculated by dividing the amount of data transferred by the real time taken for the transfer as reported by the time command.
Conclusions:
Write Speed

Memory Device	Data Transferred	Real Time Taken	Real Speed = Real Time / Data Transferred
Card 1	671 MB	98.751 s	6.79 MB/s
Card 2	671 MB	233.585 s	2.87 MB/s
Card 3	671 MB	530.657 s	1.26 MB/s
USB 1	671 MB	146.429 s	4.58 MB/s
USB 2	671 MB	78.453 s	8.55 MB/s

Read Speed

Memory Device	Data Transferred	Real Time Taken	Real Speed = Real Time / Data Transferred
Card 1	671 MB	34.039 s	19.68 MB/s
Card 2	671 MB	37.137 s	18.07 MB/s
Card 3	671 MB	51.866 s	12.94 MB/s
USB 1	671 MB	119.528 s	5.61 MB/s
USB 2	671 MB	113.329 s	5.92 MB/s

This test evaluated writing to, and reading from, a file in an 'ext3' partition of a SD card. The USB drives used were formatted in FAT32. The following memory devices were used for the test:

• Card 1 -- Class 10 Sandisk micro SD card in a Kingston Adapter
• Card 2 -- Class 4 Verbatim full size SD card
• Card 3 -- Class 4 Kingston micro SD card in a Kingston Adapter
• USB 1 -- Verbatim 4GB flash drive
• USB 2 -- Patriot Memory 8GB flash drive

Note that the use of the command "dd if=/dev/zero of=/run/media/mmcblk0p3/outfile bs=64k count=10240 conv=fdatasync" was considered, however it was determined that the output of this command was equivalent to the amount of data transferred (671 MB) divided by the real time taken for the transfer as reported by the time command. T
h4. Write Speed Tests

Card 1

root@mitysom-335x:~# time sh -c "dd if=/dev/zero of=/run/media/mmcblk0p3/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 95.5386 s, 7.0 MB/s

real    1m38.751s
user    0m0.130s
sys     0m14.290s

Card 2

root@mitysom-335x:~# time sh -c "dd if=/dev/zero of=/run/media/mmcblk0p3/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 219.389 s, 3.1 MB/s

real    3m53.585s
user    0m0.040s
sys     0m13.820s

Card 3

root@mitysom-335x:~# time sh -c "dd if=/dev/zero of=/run/media/mmcblk0p3/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 494.305 s, 1.4 MB/s

real    8m50.657s
user    0m0.080s
sys     0m14.650s

USB 1 -- Using Card 1 as the boot device

root@mitysom-335x:~# time sh -c "dd if=/dev/zero of=/run/media/sda1/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 124.768 s, 5.4 MB/s

real    2m26.429s
user    0m0.110s
sys     0m18.400s

USB 2 -- Using Card 1 as the boot device

root@mitysom-335x:~# time sh -c "dd if=/dev/zero of=/run/media/sda1/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 67.6266 s, 9.9 MB/s

real    1m18.453s
user    0m0.170s
sys     0m20.010s

Read Speed Tests¶

Card 1

root@mitysom-335x:~# time sh -c "dd of=/dev/null if=/run/media/mmcblk0p3/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 33.9662 s, 19.8 MB/s

real    0m34.039s
user    0m0.120s
sys     0m8.180s

Card 2

root@mitysom-335x:~# time sh -c "dd of=/dev/null if=/run/media/mmcblk0p3/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 37.0589 s, 18.1 MB/s

real    0m37.137s
user    0m0.200s
sys     0m7.880s

Card 3

root@mitysom-335x:~# time sh -c "dd of=/dev/null if=/run/media/mmcblk0p3/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 48.0956 s, 14.0 MB/s

real    0m51.886s
user    0m0.130s
sys     0m7.910s

USB 1 -- Using Card 1 as the boot device

root@mitysom-335x:~# time sh -c "dd of=/dev/null if=/run/media/sda1/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 119.45 s, 5.6 MB/s

real    1m59.528s
user    0m0.100s
sys     0m7.400s

USB 2 -- Using Card 1 as the boot device

root@mitysom-335x:~# time sh -c "dd of=/dev/null if=/run/media/sda1/outfile bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 113.25 s, 5.9 MB/s

real    1m53.329s
user    0m0.090s
sys     0m7.420s

Other¶

Throughput testing was performed to determine loading speeds from both the MMC/SD to RAM.

MMC/SD Card to RAM - UBoot
9588 KBytes/sec Average

ERASE RAM: mw.b 0x82000000 0xff 0x5000000
MMC LOAD: fatload mmc 0:1 82000000 root.jffs2

MMC/SD Card to RAM - Linux
TBD