QNX Momentics IDE User's Guide
QNX Software Development Platform
- Quickstart Guide
- System Architecture
  The System Architecture guide accompanies the QNX OS and is intended for both application developers and end-users.
- OS Components
  - Boot Optimization Guide
    The Boot Optimization Guide describes techniques you can use to reduce the time from your board's initial power on until you have a fully functional QNX system running on the board.
  - Building Embedded Systems
    The Building Embedded Systems guide is intended for developers who are developing or building BSPs for QNX OS embedded systems.
  - Customizing a BSP
    While QNX provides Board Support Packages (BSPs) for many common platforms and their individual variants, in some cases, you need a BSP for a board that QNX does not provide. If this is the case, you can modify a QNX BSP or develop your own.
  - High Availability Framework Developer's Guide
  - High-Performance Networking Stack (io-sock) User's Guide
    This guide contains instructions for implementing and using the QNX OS High-Performance Networking Stack and its manager, io-sock.
  - PCI Server User's Guide
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SMMUMAN User's Guide
  - SPI Framework Technote
  - System Analysis Toolkit (SAT) User's Guide
    - Introduction to the System Analysis Toolkit (SAT)
    - Events and the Kernel
    - Kernel Buffer Management
      As the instrumented kernel intercepts events, it stores them in a ring of buffers.
    - Capturing Trace Data
      - Using tracelogger to control tracing
      - Using TraceEvent() to control tracing
    - Filtering
    - Interpreting Trace Data
      Once the data has been captured, you may process it, either in real time or offline.
    - Tutorials: Controlling event tracing
    - Sample Programs
    - Current Trace Events and Data
  - Technotes
  - User's Guide
    The QNX OS User's Guide is intended for all users of a QNX OS system, from system administrators to end users.
- Graphics
- Programming
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX OS system and developers who want to create a QNX OS resource manager free from vulnerabilities.
- Utilities & Libraries
- Migrating to QNX OS 8.0
QNX Software in the Cloud
QNX Toolkit for Visual Studio Code
This User's Guide describes the QNX Toolkit for Visual Studio Code. The guide introduces you to the QNX Toolkit by explaining the QNX development environment and how to build, run, and debug your QNX OS applications and systems.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation and explains how to obtain technical support.

Capturing Trace Data

QNX SDP8.0System Analysis Toolkit (SAT) User's GuideUser

The program that captures data is the messenger between the instrumented kernel and the filesystem.

Data capture — Figure 1. Possible data capture configurations.

The main function of the data-capture program is to send the buffers given to it by the instrumented kernel to an output device (which may be a file or something else). To accomplish this function, the program must also:

interface with the instrumented kernel
specify data-filtering requirements the kernel will use

You must configure the instrumented kernel before logging. The kernel configuration settings include:

buffer allocations (size)
which events and classes of events to log (filtering)
whether to log the events in wide mode or fast mode

Note: The instrumented kernel retains the settings, and multiple programs access a single kernel configuration. Changing the settings in one process supercedes the settings made in another.

We've provided tracelogger as the default data-capture utility. Although you can write your own utility, there's little need to.

You can control the capture of data via qconn (under the control of the Integrated Development Environment, or IDE), tracelogger (from the command line), or directly from your application. All three approaches use the TraceEvent() function to control the kernel:

Trace control — Figure 2. Controlling the capture of trace data.

For information about controlling the trace from the IDE, see the Analyzing System Behavior chapter of the IDE User's Guide.

Let's look first at using tracelogger, and then we'll describe how you can use TraceEvent() to control tracing from your application.

CAUTION:

Don't run more than one instance of tracelogger at a time. Similarly, don't run tracelogger and trace events under control of the IDE at the same time.
The hardware underlying ClockCycles() must be synchronized across all processors on an SMP system. If the clocks aren't synchronized, then tracelogger produces data with inconsistent timestamps, and the IDE won't be able to load the trace file. The IDE attempts to properly order the events in the trace file, and this can go awry if the timestamp data is incorrect.
The traceprinter utility doesn't have any issues with such traces because it doesn't attempt to reorder and then interpret the data; it simply dumps the contents of each event.

Page updated: May 17, 2024