Lab: Tracing NGAP latency with bpftrace

Lab Scenario: AMF NGAP Latency

In this lab you will write a bpftrace script that measures the latency of a specific function in a running Open5GS AMF, without modifying or restarting the AMF. The target function is ogs_amf_ngap_handle_initial_ue_message — the entry point for handling NGAP InitialUEMessage from the gNB. The goal is to produce a latency histogram showing the distribution of how long this function takes to execute, broken down by approximate percentile. This is a realistic 5GC production-debugging scenario: an operator notices registration latency anomalies and wants to localize where the time is going.