In this section, we record a session with trace-cmd(1); we use a few (of the many possible) option switches to trace-cmd record; as usual, the man pages on trace-cmd-foo(1) (substitute foo with check-events, hist, record, report, reset, and so on) are very useful for finding various option switches and usage details. A few of the useful option switches particularly for trace-cmd record are as follows:
- -o: Specifies the output filename (if not specified, it defaults to trace.dat).
- -p: The plugin to use, one of function, function_graph, preemptirqsoff, irqsoff, preemptoff, and wakeup; here, in our small demo, we use the function-graph plugin (several other plugins can be configured in the kernel as well).
- -F: The command (or app) to trace; this is very useful, allowing you to specify exactly which process (or thread) to exclusively trace (otherwise, tracing all threads can result in...
