Technical data

2
Technical Overview
This chapter provides a brief technical overview of CTF.
Section 2.1 describes what tracepoints are, and describes the contents of trace
records.
Section 2.2 describes the various ways in which CTF can collect trace records
from tracepoints.
Section 2.3 describes the components of CTF that collect, store, and display trace
records.
Section 2.4 lists the files that CTF uses.
Section 2.5 provides an example of the trace output provided by CTF.
2.1 Tracepoints and Trace Records
Each networking software product that supports CTF has a number of named
tracepoints built into the software. A tracepoint usually records network protocol
data as it passes from one protocol layer to another.
When a tracepoint is reached during execution, the networking software
generates a trace record that contains:
• A trace event code, which indicates the type of event (for example, receive or
transmit) that caused the trace record to be generated. Each tracepoint has
a defined set of events that can cause a trace record to be generated at that
tracepoint.
• The size of the trace record
• The time at which the trace record was generated
• The name of the tracepoint at which the trace record was generated
• Tracepoint-specific context information
• The network protocol data itself, consisting of the protocol-specific header and
user data.
Figure 2–1 illustrates the structure of a trace record.
Technical Overview 2–1