Looks just like the SanDisk mobile Ultra 4GB microSDHC class 6 card I tested before [1].

[1]:http://lists.linaro.org/pipermail/flashbench-results/2012-February/000256.ht...

andrew@brick:~/git/flashbench$ sudo fdisk -l /dev/mmcblk0 | grep Disk Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes Disk identifier: 0x00000000 andrew@brick:~/git/flashbench$ factor $[3965190144/1024] 3872256: 2 2 2 2 2 2 2 2 2 3 2521

andrew@brick:~/git/flashbench$ sudo ./flashbench -a /dev/mmcblk0 --blocksize=$[3*1024] align 805306368 pre 752µs on 780µs post 749µs diff 28.7µs align 402653184 pre 748µs on 779µs post 748µs diff 30.8µs align 201326592 pre 748µs on 777µs post 745µs diff 30.2µs align 100663296 pre 747µs on 805µs post 743µs diff 59.9µs align 50331648 pre 747µs on 805µs post 745µs diff 59.3µs align 25165824 pre 745µs on 747µs post 743µs diff 2.51µs align 12582912 pre 744µs on 774µs post 742µs diff 31.4µs align 6291456 pre 727µs on 773µs post 734µs diff 42.3µs align 3145728 pre 726µs on 726µs post 726µs diff 106ns align 1572864 pre 726µs on 754µs post 725µs diff 29.3µs align 786432 pre 726µs on 726µs post 726µs diff 523ns align 393216 pre 728µs on 728µs post 726µs diff 836ns align 196608 pre 725µs on 726µs post 726µs diff 662ns align 98304 pre 727µs on 727µs post 726µs diff -112ns align 49152 pre 725µs on 725µs post 726µs diff -553ns align 24576 pre 726µs on 726µs post 726µs diff -319ns align 12288 pre 726µs on 726µs post 726µs diff 207ns align 6144 pre 724µs on 723µs post 728µs diff -3419ns

andrew@brick:~/git/flashbench$ sudo ./flashbench -a /dev/mmcblk0 --blocksize=$[3*1024] --count=100 align 805306368 pre 746µs on 775µs post 744µs diff 30.2µs align 402653184 pre 747µs on 777µs post 745µs diff 30.7µs align 201326592 pre 746µs on 775µs post 743µs diff 30.2µs align 100663296 pre 746µs on 804µs post 743µs diff 59.9µs align 50331648 pre 746µs on 804µs post 743µs diff 59.7µs align 25165824 pre 744µs on 744µs post 742µs diff 920ns align 12582912 pre 743µs on 773µs post 740µs diff 31.1µs align 6291456 pre 726µs on 771µs post 732µs diff 42.6µs align 3145728 pre 725µs on 724µs post 725µs diff -843ns align 1572864 pre 726µs on 754µs post 723µs diff 29.6µs align 786432 pre 725µs on 725µs post 725µs diff 573ns align 393216 pre 725µs on 724µs post 724µs diff -111ns align 196608 pre 724µs on 724µs post 724µs diff 28ns align 98304 pre 724µs on 725µs post 724µs diff 410ns align 49152 pre 724µs on 724µs post 724µs diff 151ns align 24576 pre 724µs on 725µs post 725µs diff 253ns align 12288 pre 724µs on 725µs post 725µs diff 492ns align 6144 pre 721µs on 721µs post 722µs diff -146ns

## Confusion about erase block size. Either 1.5, 2, or 6 MiB.

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[24*1024] --erasesize=$[6*1024*1024] --offset=$[24*1024*1024] --open-au-nr=1 6MiB 10.5M/s 3MiB 10.4M/s 1.5MiB 8.95M/s 768KiB 8.89M/s 384KiB 10.4M/s 192KiB 10.2M/s 96KiB 9.8M/s 48KiB 9.68M/s 24KiB 7.28M/s

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[24*1024] --erasesize=$[6*1024*1024] --offset=$[24*1024*1024] --open-au-nr=2 6MiB 10.4M/s 3MiB 10.4M/s 1.5MiB 10.4M/s 768KiB 10.4M/s 384KiB 10.1M/s 192KiB 10.2M/s 96KiB 9.61M/s 48KiB 9.23M/s 24KiB 6.35M/s

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[24*1024] --erasesize=$[6*1024*1024] --offset=$[24*1024*1024] --open-au-nr=9 6MiB 10.4M/s 3MiB 10.4M/s 1.5MiB 10.4M/s 768KiB 10.4M/s 384KiB 10.3M/s 192KiB 10.2M/s 96KiB 9.55M/s 48KiB 9.12M/s 24KiB 6.31M/s

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[24*1024] --erasesize=$[6*1024*1024] --offset=$[24*1024*1024] --open-au-nr=10 6MiB 10.4M/s 3MiB 9.36M/s 1.5MiB 6.94M/s 768KiB 5.06M/s 384KiB 3.12M/s

## 9 linear open-au.

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[24*1024] --erasesize=$[6*1024*1024] --offset=$[24*1024*1024] --random --open-au-nr=1 6MiB 10.4M/s 3MiB 9.75M/s 1.5MiB 7.51M/s 768KiB 4.83M/s 384KiB 4.04M/s 192KiB 2.5M/s 96KiB 1.51M/s 48KiB 1.32M/s 24KiB 2.94M/s

## Poor random.

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[64*1024] --erasesize=$[2*1024*1024] --offset=$[23*1024*1024] --open-au-nr=7 2MiB 7.14M/s 1MiB 7.39M/s 512KiB 7.04M/s 256KiB 6.99M/s 128KiB 6.93M/s 64KiB 6.72M/s andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[64*1024] --erasesize=$[2*1024*1024] --offset=$[24*1024*1024] --open-au-nr=7 2MiB 10.4M/s 1MiB 10.2M/s 512KiB 10.3M/s 256KiB 10.2M/s 128KiB 10M/s 64KiB 9.75M/s andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[64*1024] --erasesize=$[2*1024*1024] --offset=$[25*1024*1024] --open-au-nr=7 2MiB 8.39M/s 1MiB 7.6M/s 512KiB 7.04M/s 256KiB 7M/s 128KiB 6.92M/s 64KiB 6.72M/s

## 24MiB is erase block bound.

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[48*1024] --erasesize=$[1*1024*1024+512*1024] --offset=$[24*1024*1024+512*1024] --open-au-nr=7 1.5MiB 10.4M/s 768KiB 10.3M/s 384KiB 10.1M/s 192KiB 10.2M/s 96KiB 9.59M/s 48KiB 9.27M/s andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[48*1024] --erasesize=$[1*1024*1024+512*1024] --offset=$[24*1024*1024-512*1024] --open-au-nr=7 1.5MiB 7.19M/s 768KiB 5.1M/s 384KiB 5.63M/s 192KiB 5.78M/s 96KiB 5.57M/s 48KiB 5.5M/s andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 --open-au --blocksize=$[48*1024] --erasesize=$[1*1024*1024+512*1024] --offset=$[25*1024*1024] --open-au-nr=7 1.5MiB 7.74M/s 768KiB 5.65M/s 384KiB 4.6M/s 192KiB 4.29M/s 96KiB 4.16M/s 48KiB 5.39M/s

## Looks more like 2 MiB erase block.

andrew@brick:~/git/flashbench$ sudo ./flashbench /dev/mmcblk0 -f --erasesize=$[512*1024] --blocksize=$[32*1024] --fat-nr=30 512KiB 10.3M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.6M/s 10.5M/s 10.5M/s 10.6M/s 10.5M/s 10.5M/s 10.5M/s 10.3M/s 10.5M/s 9.84M/s 8.48M/s 10.3M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.6M/s 10.5M/s 10.6M/s 10.5M/s 10.6M/s 10.5M/s 10.4M/s 256KiB 7.71M/s 10.4M/s 10.4M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.4M/s 10.5M/s 10.5M/s 10.4M/s 5.22M/s 10.5M/s 9.8M/s 9.65M/s 10.2M/s 10.6M/s 10.5M/s 10.5M/s 10.4M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.6M/s 10.4M/s 128KiB 8.77M/s 10.3M/s 10.3M/s 10.3M/s 10.3M/s 10.4M/s 10.5M/s 10.5M/s 10.4M/s 10.5M/s 10.4M/s 10.4M/s 10.3M/s 10.3M/s 4.77M/s 9.67M/s 10.1M/s 10.4M/s 10.5M/s 10.5M/s 10.5M/s 10.5M/s 10.4M/s 10.4M/s 10.4M/s 10.4M/s 10.3M/s 10.3M/s 10.4M/s 10.4M/s 64KiB 10.1M/s 10.2M/s 10.4M/s 10.3M/s 10.4M/s 10.3M/s 10.3M/s 10.3M/s 10.3M/s 10.3M/s 10.3M/s 10.4M/s 10.1M/s 10.3M/s 4.64M/s 9.47M/s 9.98M/s 10.2M/s 10.2M/s 10.2M/s 10.3M/s 10.4M/s 10.4M/s 10.5M/s 10.3M/s 10.4M/s 10.5M/s 10.3M/s 10.4M/s 10.4M/s 32KiB 8.8M/s 9.16M/s 9.14M/s 9.25M/s 8.89M/s 9.1M/s 9.1M/s 9.17M/s 9.1M/s 9.2M/s 9.28M/s 9.27M/s 8.93M/s 9.06M/s 4.3M/s 7.92M/s 8.89M/s 9.27M/s 9.26M/s 9.35M/s 9.07M/s 9.35M/s 9.27M/s 9.18M/s 9.12M/s 9.29M/s 9.34M/s 9.28M/s 9.13M/s 9.14M/s

## 15th 512kiB erase block is slow. Interesting...

-Andrew