tracepoints

Tracepoints are instrumentation sites embedded in software where a trace event is emitted as execution reaches the point. They are used to collect structured data about program behavior, performance, and state without requiring full logging or stopping execution. Tracepoints are provided by tracing frameworks and can exist in both kernel and user-space code, enabling observability with minimal intrusion.

When a tracepoint is active, it records an event that typically includes a timestamp, process and thread identifiers, and contextual data such as the function name and selected arguments. The emitted data is consumed by a tracing backend or viewer, which can assemble it into timelines, call graphs, histograms, or flame graphs. If tracing is disabled or the event is filtered out, the overhead is kept low, though enabling tracing can incur performance costs depending on data volume and frequency.

Tracepoints can be static, built into code and compiled in, or dynamic, registered at runtime by the tracing framework. In operating systems and runtimes, tracepoints are part of a broader tracing ecosystem that may include kernel subsystems (such as Linux ftrace) and user-space tools like DTrace, SystemTap, LTTng, perf, or eBPF-based tracers. These systems define providers and probes with first-class data schemas, enabling consistent collection and analysis across components.

The primary advantages of tracepoints are low observational overhead when disabled, modular instrumentation separate from business logic, and the ability to generate rich, queryable diagnostics post hoc. Challenges include potential performance impact when heavily instrumented, complexity in managing traces and data volumes, and concerns about privacy and security when sensitive data is captured. Examples of usage span kernel tracing, application profiling, and distributed systems observability.