The usual approach to analyzing the CPU usage of Linux-based Qt applications is running them through valgrind, using the "callgrind" tool. This works well for Desktop applications and provides very accurate statistics on how an application spends its CPU time. However, for embedded devices with limited resources valgrind is not the best choice. Also, such statistics do not show the
interaction between different threads or distinguish between idle and busy periods during the run time of an application.
QtCreator 3.4 has a new CPU Usage Analyzer, specially targeted for Device Creation. It will be enabled with Boot2Qt 5.5 and it allows you to get a detailed picture of the functions where your application spends its time.
The CPU Usage Analyzer provides a zoomable timeline view like the QML Profiler, so that you can see what functions are running in what threads at any given time. In future releases a statistics view will be added. The data is collected with the Linux perf tool, which is less accurate but much faster than valgrind. This way meaningful data can be collected even on resource-constrained devices.
The talk will showcase the new functionality in a live demo.
IUlf Hermann, The Qt Company
Ulf Hermann has a degree in computer science from the Humboldt University in Berlin and has been working at Digia and The Qt Company since November 2013. His main focus are Tools for analyzing performance bottlenecks, such as the QML profiler and the CPU Usage Analyzer for Device Creation.
Speaker: Ulf Herman, The Qt Company
Session type: Qt application development and device creation
Date: Wednesday, October 7, 2015 - From 10:40 to 11:11