ardupilot version: Copter-4.3.0
I followed the tutorial "Using Linux Trace Toolkit ng (LTTng) to Create Realtime ArduPilot Traces " in the way to modify the source code to enable LTTng for performance analysis. But I found that the code described in the tutorial cannot be compiled. The reason is that functions like perf_begin are not defined and declared accordingly in the source code.
hal.util->perf_begin(my_perf);
hal.util->perf_end(my_perf).
AP_HAL::Util::perf_counter_t my_perf = hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "my_perf");