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List:       linaro-flashbench-results
Subject:    [Flashbench] Kingston 8GB Datatraveler DT101 G2
From:       arnd () arndb ! de (Arnd Bergmann)
Date:       2011-07-28 13:30:44
Message-ID: 201107281530.44593.arnd () arndb ! de
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On Thursday 28 July 2011, Ajax Criterion wrote:

> --> aligned to 4MB blocks.  FAT 32 in the front, EXT4 in the back
> again (I'll likely destroy this again with the --findfat test, but
> what the hell...  FS in the back will get changed around a lot while I
> benchmark multiple filesystems).

The --open-au test also destroys the data, you just might be able
to run a little bit longer. There is generally no reason to even
create a partition table in order to run flashbench, just boot from
a different drive than the one you want to test.
 
> bash-4.1# flashbench -O --open-au-nr=10 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096
> 4MiB    11.8M/s
> 2MiB    13.2M/s
> 1MiB    13.6M/s
> 512KiB  13.6M/s
> 256KiB  13.5M/s
> 128KiB  11.2M/s
> 64KiB   15.2M/s
> ^C
> ^C
> bash-4.1# flashbench -O --open-au-nr=13 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096
> 4MiB    6.54M/s
> 2MiB    5.55M/s
> 1MiB    5.95M/s
> 512KiB  3.15M/s
> 256KiB  2.51M/s
> 128KiB  894K/s
> 64KiB   467K/s
> ^C
> bash-4.1# flashbench -O --open-au-nr=12 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096
> 4MiB    6.07M/s
> 2MiB    5.83M/s
> 1MiB    5.9M/s
> 512KiB  5.95M/s
> 256KiB  5.45M/s
> 128KiB  4.91M/s
> 64KiB   4.82M/s
> 32KiB   4.44M/s
> 16KiB   2.86M/s
> 8KiB    772K/s
> ^C
> bash-4.1#
> 
> ---> There seems to be a clear breakdown after 12 AU's ...

Yes, that is pretty clear from your numbers.

> why am I
> bouncing around between 5-6 and 11-13 M/s??

I'm not sure, but what I can imagine is happening is that
the drive can switch each erase block between linear optimized
more (13 MB/s) and random access mode (6 MB/s). When you do
something that has a random pattern, including going beyond
12 erase blocks, it will go into the random mode, in order to
cope at all. After writing linearly a few times, the controller
decides to get back into linear optimized mode. This is
a very smart thing to do for the controller.

> bash-4.1# flashbench -O --open-au-nr=12 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096 --random
> 4MiB    11.2M/s
> 2MiB    8.51M/s
> 1MiB    5.8M/s
> 512KiB  3.6M/s
> 256KiB  5M/s
> 128KiB  3.86M/s
> 64KiB   3.12M/s
> 32KiB   3.23M/s
> 16KiB   1.89M/s
> ^C
> bash-4.1# flashbench -O --open-au-nr=13 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096 --random
> 4MiB    8.89M/s
> 2MiB    7.31M/s
> 1MiB    5.55M/s
> 512KiB  3.7M/s
> 256KiB  4.99M/s
> 128KiB  3.74M/s
> 64KiB   3.11M/s
> 32KiB   3.25M/s
> ^C
> bash-4.1# flashbench -O --open-au-nr=15 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096 --random
> 4MiB    9.85M/s
> 2MiB    7.47M/s
> 1MiB    4.7M/s
> 512KiB  2.54M/s
> 256KiB  995K/s
> ^C
> bash-4.1# flashbench -O --open-au-nr=14 /dev/sdc
> --erasesize=$[4*1024*1024] --blocksize=4096 --random
> 4MiB    7.13M/s
> 2MiB    5.82M/s
> 1MiB    4.01M/s
> 512KiB  3.67M/s
> 256KiB  4.94M/s
> 128KiB  3.23M/s
> 64KiB   3.43M/s
> 32KiB   3.37M/s
> 16KiB   1.79M/s
> ^C
> 
> --looks to be 14 open AU's for random.

Yes.

> bash-4.1# mkdir /mnt/sdc1
> bash-4.1# mount /dev/sdc1 /mnt/sdc1
> bash-4.1# umount /dev/sdc1
> 
> ---> mounts fine.

Just lucky that you didn't overwrite any actual data. flashbench does
not write into the first 16 MB on the --open-au test in order to avoid
the FAT optimized blocks, so if all your important data is there, you
won't notice the damage.

> bash-4.1# flashbench --findfat --fat-nr=8 --erasesize=$[4*1024*1024]
> --random --blocksize=512 /dev/sdc
> 4MiB    4.96M/s  13.4M/s  13.3M/s  13.4M/s  13.3M/s  13.4M/s  13.3M/s  13.3M/s
> 2MiB    5.16M/s  9.27M/s  9.28M/s  9.22M/s  9.19M/s  9.39M/s  9.16M/s  9.43M/s
> 1MiB    5.24M/s  5.86M/s  5.86M/s  5.84M/s  5.85M/s  5.9M/s   5.87M/s  5.92M/s
> 512KiB  5.29M/s  3.77M/s  3.77M/s  3.77M/s  3.77M/s  3.77M/s  3.77M/s  3.77M/s
> 256KiB  2.92M/s  5.5M/s   5.49M/s  5.51M/s  5.48M/s  5.49M/s  5.5M/s   5.46M/s
> 128KiB  4.54M/s  4.61M/s  4.61M/s  4.61M/s  4.6M/s   4.62M/s  4.6M/s   4.61M/s
> 64KiB   4.16M/s  3.58M/s  3.6M/s   3.6M/s   3.6M/s   3.59M/s  3.59M/s  3.6M/s
> 32KiB   5.61M/s  4.17M/s  4.17M/s  4.18M/s  4.19M/s  4.19M/s  4.18M/s  4.18M/s
> 16KiB   4.1M/s   2.83M/s  2.83M/s  2.83M/s  2.82M/s  2.82M/s  2.83M/s  2.82M/s
> 8KiB    1.35M/s  1.33M/s  1.33M/s  1.33M/s  1.33M/s  1.33M/s  1.33M/s  1.33M/s
> 4KiB    743K/s   839K/s   837K/s   838K/s   838K/s   838K/s   838K/s   838K/s
> ^C

I think there is nothing to see here.

> For some reason, when I run a scatter plot, I get a very long straight
> line...I'm trying to sort that out to get a better read, to verify the
> 4MB eraseblock...

It's quite possible that that's all you can get out of this drive.

	Arnd


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