View source for Introspection for Jobs: in-job monitoring of performance

Several types of data are collected about performance while a job is running; ultimately, much of this winds up in portals and can be examined.  This data is also available to the job, while it runs, and can provide additional insight.  Here, we'll demonstrate scripts that can execute within the job context to, for instance, provide summaries of performance at the job's end, or within sections of the job.