[Flashbench] Sandisk Netbook Edition 8 GB SDHC Class 2

Arnd Bergmann arnd at arndb.de
Fri Mar 18 13:40:17 UTC 2011

I wanted to find out if the Sandisk Netbook Edition does anything
particularly well for Netbooks. Apparently this is not the case,
it's a standard Sandisk Algorithm for older cards. Well, 20€ wasted ;-)

This card can write random access to 6 2MB allocation units, but does
not store a lookup table, so it always needs to garbage-collect the
allocation unit when it does this, making random access relatively

Minimum size for random-access writes is 64 KB, anything smaller
seems to do 64 KB copy-on-write.

As a twist, it can do random access to 4 segments, but linear
access to 6 segments.

$ head /sys/block/mmcblk0/device/{cid,csd,scr,*rev,*id,name,serial}
==> /sys/block/mmcblk0/device/cid <==
==> /sys/block/mmcblk0/device/csd <==
==> /sys/block/mmcblk0/device/scr <==
==> /sys/block/mmcblk0/device/fwrev <==
==> /sys/block/mmcblk0/device/hwrev <==
==> /sys/block/mmcblk0/device/cid <==
==> /sys/block/mmcblk0/device/manfid <==
==> /sys/block/mmcblk0/device/oemid <==
==> /sys/block/mmcblk0/device/name <==
==> /sys/block/mmcblk0/device/serial <==

$ sudo ./flashbench --open-au --open-au-nr=1  /dev/mmcblk0 --blocksize=8192 \
	--erasesize=$[2* 1024 * 1024]  --random
2MiB    5.34M/s 
1MiB    3.01M/s 
512KiB  2.39M/s 
256KiB  2.34M/s 
128KiB  2.37M/s 
64KiB   2.31M/s 
32KiB   1.69M/s 
16KiB   1.69M/s 
8KiB    861K/s  

$ sudo ./flashbench --open-au --open-au-nr=4  /dev/mmcblk0 --blocksize=8192 
	\--erasesize=$[2* 1024 * 1024]  --random
2MiB    4.08M/s 
1MiB    4.96M/s 
512KiB  3.05M/s 
256KiB  2.36M/s 
128KiB  2.33M/s 
64KiB   2.3M/s  
32KiB   1.91M/s 
16KiB   1.61M/s 
8KiB    835K/s  

$ sudo ./flashbench --open-au --open-au-nr=5  /dev/mmcblk0 --blocksize=8192 \
	--erasesize=$[2* 1024 * 1024]  --random
2MiB    3.32M/s 
1MiB    4.5M/s  
512KiB  3.11M/s 
256KiB  2.27M/s 
128KiB  2.14M/s 
64KiB   1.38M/s 
32KiB   715K/s  
16KiB   395K/s  
8KiB    193K/s  

$ sudo ./flashbench --open-au --open-au-nr=6  /dev/mmcblk0 --blocksize=1024 \
	--erasesize=$[2* 1024 * 1024]  
2MiB    5.36M/s 
1MiB    5.38M/s 
512KiB  5.38M/s 
256KiB  5.38M/s 
128KiB  5.38M/s 
64KiB   5.38M/s 
32KiB   4.54M/s 
16KiB   3.46M/s 
8KiB    2.59M/s 
4KiB    1.35M/s 
2KiB    631K/s  
1KiB    308K/s  

$ sudo ./flashbench --open-au --open-au-nr=7  /dev/mmcblk0 --blocksize=1024 --erasesize=$[2* 1024 * 1024]  
2MiB    5.42M/s 
1MiB    4.19M/s 
512KiB  2.15M/s 
256KiB  1.12M/s 
128KiB  583K/s  
64KiB   299K/s  
32KiB   152K/s  

$ sudo ./flashbench --findfat --fat-nr=10 /dev/mmcblk0 --blocksize=1024 --erasesize=$[2* 1024 * 1024]   --random
2MiB    5.29M/s  5.37M/s  5.38M/s  3.34M/s  3.33M/s  3.35M/s  3.35M/s  3.37M/s  5.33M/s  5.37M/s  
1MiB    4.3M/s   4.36M/s  4.37M/s  3.26M/s  4.36M/s  2.24M/s  3.65M/s  3.49M/s  3.67M/s  3.69M/s  
512KiB  3.32M/s  3.36M/s  3.36M/s  3.19M/s  3.34M/s  3.36M/s  3.35M/s  3.35M/s  3.36M/s  3.34M/s  
256KiB  3.94M/s  3.95M/s  3.91M/s  3.86M/s  3.93M/s  3.94M/s  3.8M/s   3.93M/s  3.94M/s  3.92M/s  
128KiB  4.35M/s  4.35M/s  4.34M/s  4.19M/s  4.34M/s  4.35M/s  4.35M/s  4.23M/s  4.35M/s  4.35M/s  
64KiB   4.47M/s  4.58M/s  4.58M/s  4.46M/s  4.56M/s  4.57M/s  4.57M/s  4.48M/s  4.56M/s  4.55M/s  
32KiB   3.67M/s  3.77M/s  3.73M/s  3.7M/s   3.76M/s  3.72M/s  3.76M/s  3.72M/s  3.74M/s  3.72M/s  
16KiB   2.63M/s  2.64M/s  2.65M/s  2.62M/s  2.56M/s  2.61M/s  2.62M/s  2.62M/s  2.6M/s   2.61M/s  
8KiB    1.45M/s  1.47M/s  1.48M/s  1.46M/s  1.45M/s  1.46M/s  1.46M/s  1.44M/s  1.47M/s  1.47M/s  
4KiB    647K/s   645K/s   643K/s   644K/s   642K/s   642K/s   638K/s   637K/s   638K/s   637K/s   

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