Introduction to Hotspot: The Linux Performance Analysis GUI
Hotspot is a user-friendly graphical interface designed to aid in the analysis of performance data on Linux systems. This open-source project is spearheaded by KDAB, a respected software consultancy. It was created with the goal of providing a GUI similar to KCachegrind for Linux's perf tool, which is a powerful but complex tool for profiling and analyzing performance.
Key Features
Visualizing Data
Hotspot's main function is to visually interpret data from perf.data, a file generated by the perf tool. Users can view summaries, FlameGraphs, and off-CPU analysis, among other things, through an intuitive interface. This visualization makes it easier to pinpoint performance bottlenecks in software applications.
Time Line
Hotspot offers a timeline feature that allows users to filter performance data by time, process, or thread. This dynamic capability ensures that the most relevant information is visible, helping users to zero in on specific issues that affect performance during particular time frames.
Record Data
By integrating with perf, Hotspot can be used to profile both newly launched applications and running processes. This feature is instrumental for developers trying to understand how applications are performing in real time.
Obtaining Hotspot
Hotspot can be accessed on various Linux distributions, including ArchLinux, Debian, Ubuntu, Gentoo, and Fedora. For other distributions, users can use the AppImage format, which provides an easy way to get the latest version of Hotspot without depending on specific package managers.
Building Hotspot
Although pre-built versions are available, users who want the latest updates or wish to contribute to the development may opt to compile Hotspot from source. This route requires ensuring all dependencies are in place and potentially facilitates more customization.
Using Hotspot
To begin using Hotspot, performance data needs to be recorded using perf. Once you have the data, you can launch Hotspot, which will automatically open the perf.data file, ready for analysis. There are several options available from command line arguments to fine-tune how Hotspot runs, making it versatile for many use cases.
Specialized Applications
- Off-CPU Profiling: Hotspot excels in performing off-CPU analysis, determining when a thread was not actively running on the CPU.
- Embedded Systems: For users working with embedded systems, Hotspot allows for performance data from those systems to be analyzed on more powerful host machines.
- Import/Export: Hotspot supports exporting analyzed data for easier sharing and collaboration, though current export formats may not be compatible with all other tools.
Known Issues and Limitations
As with any complex tool, there are known issues that users might encounter, such as broken backtraces if certain files are missing or debug information is incomplete. Also, there are some advanced features available in perf that are not yet supported in Hotspot.
Integration with Qt Creator
While Hotspot is a standalone application, the project draws from the perfparser utility, a tool also used by The Qt Company for performance analysis in the Qt Creator IDE.
Licensing
Hotspot is available under the GPL v2+ license, allowing it to be freely used and modified in compliance with the license terms.
In summary, Hotspot offers a powerful yet accessible way for developers to visualize and analyze performance data on Linux systems, greatly simplifying the task of identifying bottlenecks and optimizing applications.