Comment # 13 on bug 1186692 from Uwe Bonnes

> uname -a
Linux hertz 5.13.0-rc6-lp152.78-preempt_custom #4 SMP PREEMPT Thu Jun 17
13:46:19 CEST 2021 x86_64 x86_64 x86_64 GNU/Linux
> blackmagic -v3 -r /tmp/bla
...
Read/Verify succeeded for 65536 bytes,   49.091 kiB/s

This is noticable slower!

I will bisect between master and v5.8...