Hi Arnd,
Thank you for your quick reply and guidance.
I don't think there are any cards with an erase block size of 7 MB, so I don't know what's going on here.
However, this is the same size that I have seen on one of the best cards ever a Samsung 32GB class 10 microsdhc, so I would assume that this one is very similar.
Are you referring to the "essential" microSDHC 32GB (MB-MSBGA) that you mentioned in some previous post in the mailing list?
What should be the the erase block size then? 1.5 MiB or some multiple?
Can you copy the exact writing on the backside (serial number, made-in korea, ...) here so we can compare those?
Indeed it was made in Korea! Here is what is written on its backside:
MMBTR32GUBCA - AB S N3TVDD9I 203 Made in KOREA
It's definitely interesting that you see big differences between the three card readers but in the end that is not the most interesting result, so any one would do.
I'm continuing with the phone then...
What I'd like to see is the result of this test:
sudo ./flashbench --open-au --open-au-nr=1 --erasesize=$[512 * 1024] \ --blocksize=1024 /dev/mmcblk0 --offset=$[24*1024*1024] sudo ./flashbench --open-au --open-au-nr=30 --erasesize=$[512 * 1024] \ --blocksize=1024 /dev/mmcblk0 --offset=$[24*1024*1024] sudo ./flashbench --open-au --open-au-nr=31 --erasesize=$[512 * 1024] \ --blocksize=1024 /dev/mmcblk0 --offset=$[24*1024*1024]
The similar card that I have can handle 30 erase blocks being written concurrently, it would be good to know if the same is true for your card.
While doing the first series of tests I noticed a change in the speeds for the bigger blocks that became faster so did a second series for which those speeds seem more consistent. I also included the time that 2nd one. Note that after I did 2 additional tests with the --open-au-nr=1 and it seems that what I observed in the first series looks to be some singularity since I continued having consistency in the speeds in continuation with the 2nd series with values staying at around 8M/s for the 64KiB one and 9M/s or even more for the bigger ones.
The test with 31 open erase blocks seems to show a neat degradation, doesn't it? (slower speed for the small blocks and more than 4 minutes to complete)
Could we conclude that the indeed it can handle 30 concurrent open erase blocks even though it took more than 1 minute and a half?
# # First series #
# ./flashbench --open-au --open-au-nr=1 --erasesize=`dc 512 1024 mul p` \ --blocksize=1024 /dev/block/mmcblk1 --offset=`dc 24 1024 1024 mul mul p`
512KiB 706K/s 256KiB 3.57M/s 128KiB 3.48M/s 64KiB 3.41M/s 32KiB 3.27M/s 16KiB 894K/s 8KiB 456K/s 4KiB 226K/s 2KiB 363K/s 1KiB 335K/s
# ./flashbench --open-au --open-au-nr=30 --erasesize=`dc 512 1024 mul p` \ --blocksize=1024 /dev/block/mmcblk1 --offset=`dc 24 1024 1024 mul mul p`
512KiB 1.2M/s 256KiB 4.38M/s 128KiB 10.8M/s 64KiB 9.44M/s 32KiB 8.44M/s 16KiB 3.48M/s 8KiB 2.44M/s 4KiB 1.54M/s 2KiB 414K/s 1KiB 342K/s
# ./flashbench --open-au --open-au-nr=31 --erasesize=`dc 512 1024 mul p` \ --blocksize=1024 /dev/block/mmcblk1 --offset=`dc 24 1024 1024 mul mul p`
512KiB 8.53M/s 256KiB 7.68M/s 128KiB 6.91M/s 64KiB 5.51M/s 32KiB 3.7M/s 16KiB 2.22M/s 8KiB 993K/s 4KiB 523K/s 2KiB 263K/s ^C ## I interrupted it since it was taking too long time...
# # Second series with time #
# time ./flashbench --open-au --open-au-nr=1 --erasesize=`dc 512 1024 mul p` \ --blocksize=1024 /dev/block/mmcblk1 --offset=`dc 24 1024 1024 mul mul p`
512KiB 9.39M/s 256KiB 9.21M/s 128KiB 9.6M/s 64KiB 8.01M/s 32KiB 6.3M/s 16KiB 4.58M/s 8KiB 2.68M/s 4KiB 1.32M/s 2KiB 544K/s 1KiB 321K/s
real 0m 5.68s user 0m 0.47s sys 0m 1.06s
# time ./flashbench --open-au --open-au-nr=30 --erasesize=`dc 512 1024 mul p` \ --blocksize=1024 /dev/block/mmcblk1 --offset=`dc 24 1024 1024 mul mul p`
512KiB 8.89M/s 256KiB 8.54M/s 128KiB 9.37M/s 64KiB 8.07M/s 32KiB 6.01M/s 16KiB 5.23M/s 8KiB 3.14M/s 4KiB 1.49M/s 2KiB 723K/s 1KiB 344K/s
real 1m 39.40s user 0m 0.63s sys 0m 1.87s
# time ./flashbench --open-au --open-au-nr=31 --erasesize=`dc 512 1024 mul p` \ --blocksize=1024 /dev/block/mmcblk1 --offset=`dc 24 1024 1024 mul mul p`
512KiB 8.78M/s 256KiB 8.76M/s 128KiB 7.46M/s 64KiB 5.47M/s 32KiB 3.74M/s 16KiB 2.24M/s 8KiB 999K/s 4KiB 519K/s 2KiB 264K/s 1KiB 133K/s
real 4m 15.09s user 0m 1.12s sys 0m 2.02s
Thanks,
Victor