On Fri, Jun 15, 2012, at 07:44 PM, Arnd Bergmann wrote:
This resuls might be clearer in --random mode for this, but 24 MB of special area seems reasonable for a large USB device, especially if it was formatted with a small cluster size.
Sorry, forgot to include the --random test in yesterday's email.
[andrew@mythdvr flashbench]$ sudo ./flashbench /dev/sdb --findfat --erasesize=$[3*1024*1024] --blocksize=$[12*1024] --fat-nr=10 --random 3MiB 32.4M/s 32.7M/s 31.5M/s 32.7M/s 32.9M/s 31.3M/s 32.7M/s 32.9M/s 31.3M/s 32.9M/s 1.5MiB 33.7M/s 34.9M/s 33.8M/s 33.5M/s 35.4M/s 34.7M/s 34M/s 34.5M/s 7.83M/s 4.51M/s 768KiB 4.01M/s 3.35M/s 32.4M/s 4.97M/s 33.7M/s 34.3M/s 34.1M/s 13.6M/s 2.54M/s 3.56M/s 384KiB 4.04M/s 32.2M/s 32.8M/s 33.5M/s 33.1M/s 31.9M/s 32.4M/s 4.65M/s 4.8M/s 6.19M/s 192KiB 12.9M/s 30.2M/s 6.58M/s 30.3M/s 31.1M/s 4.62M/s 29.9M/s 7.52M/s 30.9M/s 5.62M/s 96KiB 11.6M/s 7.42M/s 25.1M/s 5.21M/s 11.1M/s 4.96M/s 24.9M/s 6.38M/s 3.84M/s 6.91M/s 48KiB 9M/s 16.8M/s 4.33M/s 4.3M/s 3.97M/s 8M/s 5.28M/s 7.93M/s 5.56M/s 5.23M/s 24KiB 4.12M/s 3.1M/s 5.21M/s 3.97M/s 3.69M/s 5.17M/s 3.78M/s 4.85M/s 3.94M/s 3.78M/s 12KiB 3.12M/s 1.85M/s 2.14M/s 2.03M/s 2.48M/s 2.05M/s 2.78M/s 1.38M/s 2.03M/s 2.56M/s
I'm not quite sure how to interpret that...
As a sanity check:
[andrew@mythdvr flashbench]$ sudo ./flashbench /dev/sdb --findfat --erasesize=$[3*1024*1024] --blocksize=$[12*1024] --fat-nr=10 3MiB 33.1M/s 33.6M/s 32.1M/s 33.3M/s 33.7M/s 31.9M/s 33.4M/s 33.7M/s 32M/s 33.4M/s 1.5MiB 33.2M/s 33.4M/s 31.9M/s 33.3M/s 33.5M/s 31.9M/s 33.3M/s 33.5M/s 32.9M/s 34.9M/s 768KiB 32.5M/s 33.3M/s 31.8M/s 33.3M/s 33.4M/s 32M/s 33.3M/s 33.6M/s 31.9M/s 33.5M/s 384KiB 30.9M/s 31.7M/s 30.7M/s 31.7M/s 31.8M/s 30.2M/s 31.7M/s 31.9M/s 31.9M/s 33.9M/s 192KiB 32.3M/s 32.9M/s 31.7M/s 32.8M/s 33M/s 31.5M/s 33M/s 33.2M/s 31.6M/s 33M/s 96KiB 32.6M/s 33.5M/s 32.3M/s 33.5M/s 33.7M/s 32M/s 33.7M/s 33.9M/s 31M/s 33.2M/s 48KiB 29.9M/s 30.1M/s 28.9M/s 30.2M/s 30.2M/s 29M/s 30.1M/s 30.2M/s 29M/s 30.1M/s 24KiB 24.1M/s 24.6M/s 23.8M/s 24.6M/s 24.6M/s 23.3M/s 24.6M/s 24.6M/s 23.2M/s 23.6M/s 12KiB 18.8M/s 18.8M/s 19.3M/s 19.1M/s 18.9M/s 10.4M/s 7.17M/s 10.2M/s 3.45M/s 9.16M/s
Now, that's looking like 15MiB of special area... It seems that every time I run --findfat I think something different. At least the first 5 to 8 3MiB erase blocks are probably special area for the FAT.
[andrew@mythdvr flashbench]$ sudo ./flashbench /dev/sdb --findfat --erasesize=$[8*1024*1024] --blocksize=$[16*1024] --fat-nr=6 8MiB 22.5M/s 33.1M/s 33.1M/s 32.9M/s 32.8M/s 32.8M/s 4MiB 32.9M/s 32.7M/s 32.8M/s 32.8M/s 32.8M/s 32.7M/s 2MiB 32.7M/s 32.5M/s 32.7M/s 32.8M/s 32.7M/s 32.7M/s 1MiB 33.3M/s 33.2M/s 33.4M/s 33.3M/s 33.3M/s 33.1M/s 512KiB 32.4M/s 30.3M/s 32.3M/s 32.2M/s 32.3M/s 32.3M/s 256KiB 30.9M/s 30.7M/s 30.7M/s 30.8M/s 30.7M/s 30.9M/s 128KiB 29.5M/s 29.4M/s 29.5M/s 29.4M/s 29.4M/s 29.3M/s 64KiB 30.8M/s 30.6M/s 30.5M/s 30.4M/s 30.5M/s 30.5M/s 32KiB 26.1M/s 26.2M/s 26.2M/s 26.3M/s 26.2M/s 26.4M/s 16KiB 19.5M/s 19.5M/s 19.4M/s 14M/s 11.8M/s 14.7M/s [andrew@mythdvr flashbench]$ sudo ./flashbench /dev/sdb --findfat --erasesize=$[8*1024*1024] --blocksize=$[16*1024] --fat-nr=6 --random 8MiB 33.1M/s 16.3M/s 33.2M/s 32.8M/s 33M/s 32.8M/s 4MiB 33.9M/s 33.8M/s 34.1M/s 34.1M/s 34.7M/s 21.6M/s 2MiB 12.6M/s 12.7M/s 10.6M/s 16.1M/s 10.4M/s 10.5M/s 1MiB 6.87M/s 8.91M/s 8.9M/s 11.4M/s 11.5M/s 12.7M/s 512KiB 10.4M/s 11.3M/s 11.2M/s 7.86M/s 9.09M/s 13.1M/s 256KiB 8.83M/s 12.4M/s 12.4M/s 12.1M/s 9.96M/s 9.96M/s 128KiB 9.47M/s 6.13M/s 9.05M/s 8.93M/s 7.73M/s 8.95M/s 64KiB 8.07M/s 7.66M/s 7.59M/s 7.59M/s 7.58M/s 7.58M/s 32KiB 4.11M/s 6.08M/s 6.1M/s 6.07M/s 6.09M/s 6.08M/s 16KiB 2.67M/s 1.96M/s 2.42M/s 1.98M/s 2.46M/s 1.97M/s
With 8MiB erase blocks, --findfat and --random don't seem to show much... Just regular --findfat seems to show the first 3 eraseblocks as special.
Thanks, Andrew