[Nouveau] [Intel-gfx] [PATCH 0/7] Per client engine busyness

[arabek]

> Well if it becomes a problem fixing the debugfs "clients" file and
> making it sysfs shouldn't be much of a problem later on.

Why not to try using something in terms of perf / opensnoop or bpf
to do the work. Should be optimal enough.

ie.
http://www.brendangregg.com/blog/2014-07-25/opensnoop-for-linux.html
https://man7.org/linux/man-pages/man2/bpf.2.html