Open Source Summit + AI_dev Japan 2024

trace-cmd is a front end tool to the tracefs infrastructure as well as ftrace (the mechanism that supplies function tracing). But like all tools, it's limited in what it can provide by the interface it has. Luckily, the guts of trace-cmd is being extracted into libraries. The libtracefs library is an interface to facilitate any application to access the tracefs kernel interface. This makes it easy for applications enable tracing of various events with various filters. Then there's the libtracecmd library that can be used for creating and reading the trace.dat file (the file that trace-cmd creates). By using this library, you can enable tracing on a system and then do offline analysis. Finally, there's a new library called libtraceeval that is used to help keep track of the interactions of various trace events. This talk will show some simple tools that utilize these libraries (for example, a tool that shows how much tasks are sleeping, blocked, running, and preempted). And also show i bit of the interface of the libraries to demonstrate how simple they really are.