UKUUG DTrace Talk

After their 2004 AGM UKUUG arranged for Jon Haslam, a Software Engineer at Sun Microsystems, to give a presentation on DTrace. While I missed the first thirty minutes of slides I did get to see the ninety minutes of practical demonstrations.

The official DTrace spiel, “Dynamic Tracing (DTrace) is one of the hot, new technologies in the next revision of Sun’s Operating System, Solaris 10. DTrace provides the ability to generate concise answers to almost arbitrary questions about the behaviour of your systems, from the top of the application through to the bottom of the kernel.” sounds quite impressive. What surprised me is that it seemed to work perfectly.

Jon Haslam stood in front of the audience and wrote small four to ten line scripts, while keeping everyone amused with anecdotes, that drilled down on information such as what thread (or process) was writing to which disk blocks (which you can’t do in Linux at all), what was actually causing the most interrupts (which top doesn’t actually catch as it’s granularity is too large) and other similar feats. For a full example of how simple the tool is to use have a look at TCP by process