Systemtap supports a number of built-in events. The library of scripts that comes with systemtap, each called a "tapset", may define additional ones defined in terms of the built-in family. See the stapprobes man page for details. All these events are named using a unified syntax that looks like dot-separated parameterized identifiers:

We will use as a demonstration case that you would like to trace all function entries and exits in a source file, for example net/socket.c in the kernel. The kernel.function probe point lets you express that easily, since systemtap examines the kernel's debugging information to relate object code to source code. It works like a debugger: if you can name or place it, you can probe it. Use kernel.function("*@net/socket.c") for the function entries, and kernel.function("*@net/socket.c").return for the exits. Note the use of wildcards in the function name part, and the subsequent @FILENAME part. You can also put wildcards into the file name, and even add a colon (:) and a line number, if you want to restrict the search that precisely. Since systemtap will put a separate probe in every place that matches a probe point, a few wildcards can expand to hundreds or thousands of probes, so be careful what you ask for.

Once you identify the probe points, the skeleton of the systemtap script appears. The probe keyword introduces a probe point, or a comma-separated list of them. The following { and } braces enclose the handler for all listed probe points.

You can run this script as is, though with empty handlers there will be no output. Put the two lines into a new file. Run stap -v FILE. Terminate it any time with ^C. (The -v option tells systemtap to print more verbose messages during its processing. Try the -h option to see more options.)