Yeah, ftrace is great and the trace-cmd frontend too. Another swiss-army-knife type of a tool, like perf... and is also available in older kernels.

One thing that I had missed was function call argument tracing, but looks like ftrace will soon have it too:

https://lwn.net/Articles/1003386/

https://lpc.events/event/11/contributions/1106/attachments/7...