So, I finally tried the BFQ scheduler as Carsten suggested. I tested it eg. using youtube-dl to download a big video from Vimeo (it creates/remove quickly a lot of temp files that baloo indexes every time causing a lot of IO), while Qbittorrent was downloading several big files... So 100% disk activity going on (monitored with iotop). Overloading the disk queue this way, with BFQ enabled, the result was that the video playback of a 1080p movie by VLC was smooth and didn't hang/freeze at all. I can assume BFQ was able to handle better all the stuff going on. So thanks Carsten for the suggestion :) This fixed (or at least worked around) the problem. It remains to understand why on Debian and derivs. this issue doesn't exist. Maybe the CONFIG_PREEMPT_VOLUNTARY=y set by default on kernel's config or some other block device related configs I don't have the skill (and the time) to inspect now. Cheers -- fp
