Another quite good Samsung card.

root@localhost:~/flashbench# head /sys/block/mmcblk1/device/* 2>/dev/null | grep -v ^$ ==> /sys/block/mmcblk1/device/block <== ==> /sys/block/mmcblk1/device/cid <== 1b534d303030303010a46d02c100e127 ==> /sys/block/mmcblk1/device/csd <== 400e00325b590000773c7f800a40409b ==> /sys/block/mmcblk1/device/date <== 01/2014 ==> /sys/block/mmcblk1/device/driver <== ==> /sys/block/mmcblk1/device/erase_size <== 512 ==> /sys/block/mmcblk1/device/fwrev <== 0x0 ==> /sys/block/mmcblk1/device/hwrev <== 0x1 ==> /sys/block/mmcblk1/device/manfid <== 0x00001b ==> /sys/block/mmcblk1/device/name <== 00000 ==> /sys/block/mmcblk1/device/oemid <== 0x534d ==> /sys/block/mmcblk1/device/power <== ==> /sys/block/mmcblk1/device/preferred_erase_size <== 4194304 ==> /sys/block/mmcblk1/device/scr <== 02b5800200000000 ==> /sys/block/mmcblk1/device/serial <== 0xa46d02c1 ==> /sys/block/mmcblk1/device/subsystem <== ==> /sys/block/mmcblk1/device/type <== SD ==> /sys/block/mmcblk1/device/uevent <== DRIVER=mmcblk MMC_TYPE=SD MMC_NAME=00000 MODALIAS=mmc:block

root@localhost:~/flashbench# fdisk -l /dev/mmcblk1

Disk /dev/mmcblk1: 16.0 GB, 16003891200 bytes 255 heads, 63 sectors/track, 1945 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000

Device Boot Start End Blocks Id System /dev/mmcblk1p1 1 1946 15624704 c W95 FAT32 (LBA)

root@localhost:~/flashbench# factor 16003891200 16003891200: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 5 5 11 37

root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 -a --blocksize=1024 --count=100 align 4294967296 pre 350µs on 485µs post 350µs diff 135µs align 2147483648 pre 352µs on 486µs post 350µs diff 135µs align 1073741824 pre 354µs on 485µs post 348µs diff 135µs align 536870912 pre 351µs on 486µs post 349µs diff 136µs align 268435456 pre 353µs on 485µs post 353µs diff 132µs align 134217728 pre 352µs on 487µs post 350µs diff 136µs align 67108864 pre 351µs on 485µs post 352µs diff 133µs align 33554432 pre 351µs on 483µs post 349µs diff 133µs align 16777216 pre 350µs on 485µs post 349µs diff 136µs align 8388608 pre 347µs on 498µs post 361µs diff 144µs align 4194304 pre 377µs on 488µs post 363µs diff 118µs align 2097152 pre 378µs on 485µs post 360µs diff 116µs align 1048576 pre 352µs on 487µs post 361µs diff 130µs align 524288 pre 375µs on 487µs post 362µs diff 118µs align 262144 pre 378µs on 488µs post 363µs diff 117µs align 131072 pre 377µs on 476µs post 359µs diff 108µs align 65536 pre 376µs on 484µs post 360µs diff 117µs align 32768 pre 378µs on 489µs post 360µs diff 120µs align 16384 pre 350µs on 460µs post 351µs diff 110µs align 8192 pre 353µs on 356µs post 353µs diff 2.79µs align 4096 pre 358µs on 353µs post 353µs diff -2687ns align 2048 pre 358µs on 359µs post 358µs diff 771ns

Might be 8 MiB erase blocks.

root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 --open-au --blocksize=$[16*1024] --erasesize=$[8*1024*1024] --open-au-nr=1 8MiB 13.6M/s 4MiB 13.6M/s 2MiB 13.6M/s 1MiB 13.5M/s 512KiB 13.5M/s 256KiB 13.2M/s 128KiB 12.6M/s 64KiB 11.5M/s 32KiB 9.83M/s 16KiB 6.63M/s root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 --open-au --blocksize=$[16*1024] --erasesize=$[8*1024*1024] --open-au-nr=2 8MiB 13.6M/s 4MiB 13.7M/s 2MiB 13.6M/s 1MiB 13.6M/s 512KiB 13.4M/s 256KiB 13.2M/s 128KiB 12.6M/s 64KiB 11.4M/s 32KiB 9.87M/s 16KiB 6.66M/s root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 --open-au --blocksize=$[16*1024] --erasesize=$[8*1024*1024] --open-au-nr=7 8MiB 13.7M/s 4MiB 13.7M/s 2MiB 13.7M/s 1MiB 13.6M/s 512KiB 13.5M/s 256KiB 13.3M/s 128KiB 12.6M/s 64KiB 11.5M/s 32KiB 9.92M/s 16KiB 6.69M/s root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 --open-au --blocksize=$[16*1024] --erasesize=$[8*1024*1024] --open-au-nr=20 8MiB 13.7M/s 4MiB 13.7M/s 2MiB 13.7M/s 1MiB 13.6M/s 512KiB 13.5M/s 256KiB 13.3M/s 128KiB 12.6M/s 64KiB 11.5M/s 32KiB 9.99M/s 16KiB 6.72M/s

root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 --open-au --blocksize=$[16*1024] --erasesize=$[8*1024*1024] --random --open-au-nr=20 8MiB 13.7M/s 4MiB 13.7M/s 2MiB 13.7M/s 1MiB 13.6M/s 512KiB 13.5M/s 256KiB 13.3M/s 128KiB 12.6M/s 64KiB 11.5M/s 32KiB 9.96M/s 16KiB 4.15M/s

root@localhost:~/flashbench# ./flashbench /dev/mmcblk1 --find-fat 4MiB 13.3M/s 13.8M/s 13.7M/s 13.8M/s 13.6M/s 13.7M/s 2MiB 13.5M/s 13.6M/s 13.8M/s 13.8M/s 13.6M/s 13.8M/s 1MiB 13.7M/s 13.7M/s 13.7M/s 13.7M/s 13.6M/s 13.7M/s 512KiB 13.5M/s 13.5M/s 13.5M/s 13.6M/s 13.5M/s 13.6M/s 256KiB 13.3M/s 13.4M/s 13.1M/s 13.3M/s 13.3M/s 13.4M/s 128KiB 12.6M/s 12.6M/s 12.7M/s 12.7M/s 12.6M/s 12.7M/s 64KiB 11.5M/s 11.5M/s 11.5M/s 11.5M/s 11.5M/s 11.5M/s 32KiB 10M/s 9.92M/s 10.1M/s 9.93M/s 10M/s 10M/s 16KiB 6.74M/s 6.68M/s 6.76M/s 6.68M/s 6.73M/s 6.71M/s

-Andrew