I use profiling in trace mode in my app. I want to know whether I still need to manually add functions that start and stop spans, or whether the profiler starts and stops automatically.

No, you do not need to manually start and stop spans when you use profiling in trace mode. Enable automatic tracing instrumentation, as described in your SDK's profiling documentation. You can still add manual instrumentation if you need it.

In trace mode, the profiler runs while at least one span is active and stops when no spans are active.