Bad read performance on x86_64 Linux (Arch Linux)

[raven2cz]

It seems that there is not just write performance problem, but the read problems with fuse too.
I'm trying to play movie from cloud by mpv and checking the state of mpv cache.
There is visible that the cache has problem with filling, there is cca 1-2s / 5-20MB download speed, which is very poor, it is not possible to play anything.
But sometimes it "JUMPS" and there is big download for example 60s / 150MB. This is not problem of mpv, but the reading speed or some buffer lengths problems. But it seems that this is a bug, because this jump between slow and fast reading is very visible in the cache processing!