Specifying where to send the output

Because the circular linked list of buffers can't hope to store a complete log of event activity for any significant amount of time, the tracebuffer must be handed off to a data-capture program. Normally the data-capture program pipes the information to either an output device or a file.

By default, the tracelogger utility saves the output in the binary file /dev/shmem/tracebuffer.kev, but you can use the -f option to specify a different path. The .kev extension is short for “kernel events”; you can use a different extension, but the IDE recognizes .kev and automatically uses the System Profiler to open such files.

You can also map the file in shared memory (-M), but you must then also specify the maximum size for the file (-S).