FYI, tracing supports arbitrary spans at whatever level of granularity you want. However, out of the box auto-tracing is not going to do this, it depends on the language but usually the spans are at the RPC layer of abstraction, so any fine grained spans would be fully custom code.

We did this a while back for some critical functions in our rails monolith where we wanted to confirm that an expensive bit of code was behaving as expected. It’s not bad when the service is already set up with tracing libraries and the rest of the plumbing.