Myself I've only built simple things, like tracing sched switch events for certain threads, and killing the process if they happen (specifically designed as a safety for pinned threads).
Same here, until now. I built the earlier xcapture v1 (also in the repo) about 5 years ago and it just samples various /proc/PID/task/TID pseudofiles regularly, it also allows you get pretty far with the thread-level activity measurement approach, especially when combined with always-on low frequency on-CPU sampling with perf.
