built latest kernel source from hikey branch, debootstrap ubuntu wily rootfs on hikey. Did a rough write performance testing on both internal emmc and external sdcard, which is a class 4 card.
result as following:
Internal eMMC:
root@linaro-developer:~# dd if=/dev/zero of=/root/testfile bs=512M count=1 oflag=direct
1+0 records in
1+0 records out
536870912 bytes (537 MB) copied, 46.6476 s, 11.5 MB/s
External SDcard:
root@linaro-developer:~# dd if=/dev/zero of=/root/testfile bs=512M count=1 oflag=direct
1+0 records in
1+0 records out
536870912 bytes (537 MB) copied, 60.9094 s, 8.8 MB/s
What sort of SD card are you using?
This is what I consistently see on a MicroSD UHC-I:
[root@96 ~]$ dd if=/dev/zero of=mnt/testfile bs=512M count=1 oflag=direct
1+0 records in
1+0 records out
536870912 bytes (537 MB) copied, 41.6291 s, 12.9 MB/s
Is yours a class-10 SD card? mine is class-4.
yes, class 10.
