Overview

The distributed tracing system like the perf in for process, the distributed tracing trace the RPC but perf trace the function calling.

Basic concepts

1. Trace, a whole RPC chain tracing, consist by spans (DAG structured)
2. Span, a once RPC tracing
3. Tow relationship inter span, ChildOf, FollowOf

Inter-Process

To tracing inter process, we must record the relationship inter span. So the one method is to propagating the context of span with RPC calling as below:

A --SpanA_context-> B
 |--SpanA_context-> C --SpanC_context-> D
                    | --SpanC_context-> E

Transfer:
context --inject-> Writer/Reader --Extract-> context

The context maybe consists by TraceId, SpanId and ParentId etc.

Reference