Samsung 32GB Class 10 SD-Card - Flashbench-results

14 Mar 2013


      Hi,
I have following cheaply bought SD-Card from Ebay:
Samsung 32 GB
MB-SSBGA
MBSSBGVEOBGA-SH
D 13CG5000 1 3 6
$:/sys/block/mmcblk0/device# head
/sys/block/mmcblk0/device/{c*,scr,*rev,*id,serial,*size}
==> /sys/block/mmcblk0/device/cid <==
1b534d3030303030107677b02300c100
==> /sys/block/mmcblk0/device/csd <==
400e00325b590000e9e57f800a404000
==> /sys/block/mmcblk0/device/scr <==
02b5800200000000
==> /sys/block/mmcblk0/device/fwrev <==
0x0
==> /sys/block/mmcblk0/device/hwrev <==
0x1
==> /sys/block/mmcblk0/device/cid <==
1b534d3030303030107677b02300c100
==> /sys/block/mmcblk0/device/manfid <==
0x00001b
==> /sys/block/mmcblk0/device/oemid <==
0x534d
==> /sys/block/mmcblk0/device/serial <==
0x7677b023
==> /sys/block/mmcblk0/device/erase_size <==
512
==> /sys/block/mmcblk0/device/preferred_erase_size <==
4194304
and here is the first Benchmark which is for me hard to interprete:
root@ThinkPad-T400:~/flashbench/flashbench# ./flashbench -a /dev/mmcblk0
--blocksize 1024 --count=100
align 8589934592 pre 208µs on 221µs post 206µs diff 14.3µs
align 4294967296 pre 207µs on 223µs post 208µs diff 15.1µs
align 2147483648 pre 205µs on 219µs post 207µs diff 13µs
align 1073741824 pre 257µs on 305µs post 241µs diff 56.7µs
align 536870912 pre 225µs on 261µs post 225µs diff 36µs
align 268435456 pre 294µs on 387µs post 281µs diff 100µs
align 134217728 pre 239µs on 285µs post 234µs diff 48.1µs
align 67108864 pre 222µs on 267µs post 220µs diff 46.6µs
align 33554432 pre 211µs on 257µs post 218µs diff 41.8µs
align 16777216 pre 231µs on 296µs post 237µs diff 61.8µs
align 8388608 pre 224µs on 260µs post 225µs diff 36.2µs
align 4194304 pre 222µs on 259µs post 227µs diff 34.4µs
align 2097152 pre 230µs on 260µs post 213µs diff 38.6µs
align 1048576 pre 218µs on 254µs post 223µs diff 33.8µs
align 524288 pre 234µs on 266µs post 216µs diff 40.7µs
align 262144 pre 224µs on 258µs post 224µs diff 33.3µs
align 131072 pre 228µs on 257µs post 210µs diff 37.8µs
align 65536 pre 212µs on 248µs post 216µs diff 33.8µs
align 32768 pre 223µs on 253µs post 205µs diff 38.3µs
align 16384 pre 239µs on 258µs post 234µs diff 21.3µs
align 8192 pre 233µs on 233µs post 233µs diff 424ns
align 4096 pre 234µs on 240µs post 234µs diff 5.88µs
align 2048 pre 233µs on 234µs post 234µs diff 584ns
in other outputs there are more or less only two steps (at eraseblock size
and blocksize) and they are differently ordered. The Debug FS says erase
block should be 4 MB but from this Benchmark I would suggest something like
2GB?!? Or is it 128MB ? Blocksize is 16KB i would suggest but I could be
wrong ... could you help me ? I will give the other results if the block
sizes are more clear to me...