Yeah, I wonder how much of an improvement it will be on small, cheap, low I/O devices, any insight if you can prioritize some I/O over other I/O (like user interactive stuff vs Nautilus or cp duplicating a file)?
Here's the page on the BFQ I/O scheduler: http://algo.ing.unimo.it/people/paolo/disk_sched/
Here's a list of precompiled kernels that have been patched with BFQ (and often some more desktop-use tuning): https://liquorix.net/#install for ubuntu and debian
https://www.archlinux.org/packages/extra/x86_64/linux-zen/ for archlinux
http://download.opensuse.org/repositories/home:/tiwai:/bfq/ for opensuse, BFQ as a kernel module
If you're wary of installing things outside of official repositories or compiling your own kernel, then archlinux is the only distro with a kernel option that has BFQ.
You've answered yourself there: for desktop use. Desktop is a very low priority in the Linux world, as proven by the long history of ignoring desktop-friendly schedulers over and over.
BFQ hasn't been mainlined because it is written for the legacy block layer in the Linux kernel, which will be replaced entirely with the new block multiqueue implementation. It doesn't make much sense to replace CFQ or add a brand new scheduler only to rip it out in a few releases. Linux 4.11 will have support for I/O scheduling for blk-mq. BFQ is currently being ported to blk-mq; that work is the first big hurdle to getting it merged.
From the page you linked:
> BFQ is the default I/O scheduler in Manjaro, Mageia, OpenMandriva, Sabayon, Arch Linux ARM (for Marvell Kirkwood) and ROSA ...