f2fs 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=3527: Sun Dec  6 23:53:50 2020
  write: IOPS=4878, BW=19.1MiB/s (19.0MB/s)(2779MiB/145822msec); 0 zone resets
    slat (nsec): min=2400, max=244160, avg=4173.32, stdev=504.66
    clat (nsec): min=400, max=295272k, avg=78644.13, stdev=3399292.96
     lat (usec): min=12, max=295277, avg=83.02, stdev=3399.29
    clat percentiles (usec):
     |  1.00th=[    12],  5.00th=[    13], 10.00th=[    13], 20.00th=[    13],
     | 30.00th=[    14], 40.00th=[    14], 50.00th=[    14], 60.00th=[    14],
     | 70.00th=[    14], 80.00th=[    14], 90.00th=[    15], 95.00th=[    16],
     | 99.00th=[    19], 99.50th=[    21], 99.90th=[    24], 99.95th=[    35],
     | 99.99th=[187696]
   bw (  KiB/s): min= 3872, max=211120, per=100.00%, avg=47426.20, stdev=60778.30, samples=120
   iops        : min=  968, max=52780, avg=11856.57, stdev=15194.58, samples=120
  lat (nsec)   : 500=0.01%, 750=0.01%, 1000=0.01%
  lat (usec)   : 2=0.01%, 10=0.01%, 20=99.48%, 50=0.46%, 100=0.01%
  lat (usec)   : 250=0.01%, 500=0.01%
  lat (msec)   : 100=0.01%, 250=0.04%, 500=0.01%
  cpu          : usr=1.67%, sys=3.47%, ctx=711427, majf=0, minf=32
  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=0,711395,0,0 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=19.1MiB/s (19.0MB/s), 19.1MiB/s-19.1MiB/s (19.0MB/s-19.0MB/s), io=2779MiB (2914MB), run=145822-145822msec

Disk stats (read/write):
  mmcblk1: ios=0/5559, merge=0/0, ticks=0/8376671, in_queue=8376671, util=96.17%