Hi Arnd, As you asked for flashbench results, here's some:
Transcend µSDcard 2GB : flashbench -a /dev/mmcblk1 align 536870912 pre 3.24ms on 3.8ms post 2.67ms diff 845µs align 268435456 pre 3.05ms on 3.6ms post 2.53ms diff 814µs align 134217728 pre 3.11ms on 3.65ms post 2.56ms diff 814µs align 67108864 pre 3.07ms on 3.65ms post 2.52ms diff 854µs align 33554432 pre 3.08ms on 3.63ms post 2.49ms diff 851µs align 16777216 pre 3.09ms on 3.59ms post 2.58ms diff 756µs align 8388608 pre 3.25ms on 3.82ms post 2.68ms diff 850µs align 4194304 pre 2.93ms on 3.5ms post 2.52ms diff 772µs align 2097152 pre 2.96ms on 3.51ms post 2.49ms diff 788µs align 1048576 pre 2.45ms on 2.5ms post 2.47ms diff 37.6µs align 524288 pre 2.46ms on 2.47ms post 2.5ms diff -7440ns align 262144 pre 2.45ms on 2.47ms post 2.51ms diff -13815n align 131072 pre 2.45ms on 2.47ms post 2.49ms diff 2.15µs align 65536 pre 2.45ms on 2.47ms post 2.49ms diff -1188ns align 32768 pre 2.45ms on 2.46ms post 2.5ms diff -15476n Seems to be a 2MiB eraseblock
Kingston µSD-HC card 4GB: flashbench -a /dev/mmcblk1 align 1073741824 pre 1.76ms on 2.09ms post 1.86ms diff 280µs align 536870912 pre 1.75ms on 2.09ms post 1.88ms diff 274µs align 268435456 pre 1.76ms on 2.1ms post 1.88ms diff 279µs align 134217728 pre 1.75ms on 2.1ms post 1.89ms diff 275µs align 67108864 pre 1.75ms on 2.11ms post 1.9ms diff 282µs align 33554432 pre 1.74ms on 2.09ms post 1.91ms diff 269µs align 16777216 pre 1.92ms on 2.26ms post 1.88ms diff 362µs align 8388608 pre 1.76ms on 2.1ms post 1.87ms diff 280µs align 4194304 pre 1.75ms on 2.09ms post 1.88ms diff 268µs align 2097152 pre 1.72ms on 1.91ms post 1.88ms diff 110µs align 1048576 pre 1.85ms on 2.02ms post 1.85ms diff 171µs align 524288 pre 1.72ms on 1.88ms post 1.85ms diff 98.5µs align 262144 pre 1.72ms on 1.91ms post 1.88ms diff 108µs align 131072 pre 1.73ms on 1.9ms post 1.87ms diff 96.3µs align 65536 pre 1.72ms on 1.9ms post 1.86ms diff 105µs align 32768 pre 1.72ms on 1.88ms post 1.85ms diff 89.5µs Seems to be a standard 4MiB eraseblock.
Emmc 32GB: ./flashbench -a /dev/mmcblk0 align 8589934592 pre 467µs on 470µs post 470µs diff 1.25µs align 4294967296 pre 470µs on 469µs post 466µs diff 976ns align 2147483648 pre 472µs on 473µs post 476µs diff -1154ns align 1073741824 pre 479µs on 487µs post 483µs diff 5.83µs align 536870912 pre 474µs on 480µs post 481µs diff 2.9µs align 268435456 pre 490µs on 497µs post 486µs diff 8.85µs align 134217728 pre 485µs on 485µs post 486µs diff -145ns align 67108864 pre 491µs on 493µs post 480µs diff 7.05µs align 33554432 pre 495µs on 490µs post 495µs diff -4414ns align 16777216 pre 491µs on 496µs post 495µs diff 2.32µs align 8388608 pre 500µs on 504µs post 491µs diff 8.27µs align 4194304 pre 475µs on 492µs post 497µs diff 6.63µs align 2097152 pre 478µs on 477µs post 481µs diff -1896ns align 1048576 pre 481µs on 488µs post 488µs diff 3.58µs align 524288 pre 489µs on 489µs post 484µs diff 2.3µs align 262144 pre 487µs on 485µs post 479µs diff 1.92µs align 131072 pre 477µs on 477µs post 486µs diff -4437ns align 65536 pre 484µs on 487µs post 481µs diff 4.52µs align 32768 pre 485µs on 478µs post 484µs diff -6095ns I didn't see a pattern on this one.
regards, Richard