ext4 on sd

root@macchiatobin:/tmp/sd# fio --name=random-write --ioengine=io_uring --rw=randwrite --bs=4k --numjobs=1 --size=4g --iodepth=1 --runtime=60 --time_based --end_fsync=1
random-write: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=io_uring, iodepth=1
fio-3.21
Starting 1 process
random-write: Laying out IO file (1 file / 4096MiB)
Jobs: 1 (f=1): [F(1)][100.0%][eta 00m:00s]
random-write: (groupid=0, jobs=1): err= 0: pid=3195: Sun Dec  6 21:32:36 2020
  write: IOPS=1625, BW=6501KiB/s (6657kB/s)(2905MiB/457579msec); 0 zone resets
    slat (nsec): min=2200, max=174000, avg=3675.65, stdev=563.41
    clat (nsec): min=440, max=38851k, avg=75243.01, stdev=1226018.97
     lat (usec): min=11, max=38854, avg=79.15, stdev=1226.02
    clat percentiles (usec):
     |  1.00th=[   12],  5.00th=[   12], 10.00th=[   12], 20.00th=[   13],
     | 30.00th=[   13], 40.00th=[   13], 50.00th=[   13], 60.00th=[   14],
     | 70.00th=[   14], 80.00th=[   15], 90.00th=[   15], 95.00th=[   16],
     | 99.00th=[   21], 99.50th=[   23], 99.90th=[26608], 99.95th=[28705],
     | 99.99th=[28967]
   bw (  KiB/s): min= 6400, max=229856, per=100.00%, avg=49930.55, stdev=76741.82, samples=119
   iops        : min= 1600, max=57464, avg=12482.66, stdev=19185.49, samples=119
  lat (nsec)   : 500=0.01%, 750=0.01%
  lat (usec)   : 10=0.07%, 20=98.79%, 50=0.87%, 100=0.01%, 250=0.01%
  lat (usec)   : 500=0.01%
  lat (msec)   : 4=0.01%, 20=0.13%, 50=0.13%
  cpu          : usr=0.68%, sys=0.92%, ctx=743783, majf=0, minf=31
  IO depths    : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     issued rwts: total=0,743711,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=1

Run status group 0 (all jobs):
  WRITE: bw=6501KiB/s (6657kB/s), 6501KiB/s-6501KiB/s (6657kB/s-6657kB/s), io=2905MiB (3046MB), run=457579-457579msec

Disk stats (read/write):
  mmcblk1: ios=0/169756, merge=0/3448, ticks=0/27236982, in_queue=27236983, util=98.81%