Friday, December 18, 2009

Diver's going to Spain!

A paper based on some of the innovations in Diver has been accepted to the 2010 European Conference on Software Maintenance and Reengineering. I will be presenting the paper in Madrid in March.

A lot of technical and technological innovation does come from academia. You don't always see it directly in the commercial products right away, but I do believe that it has influence. Especially as software engineering and computer science graduates move into industry, bringing their research expertise with them. A lot of the things that we take for granted in our IDEs were first written up in academic conferences or journals. Take the interactive debugger that we all use all the time as an example [Isoda, 87]. I think that industry and academia really benefit from good research relationships.

Anyway, it turns out that the way that Diver reduces the size of trace visualizations (in the sequence diagram) by cross-linking the trace with the source code is actually a new idea. So, the nice people at CSMR decided to let me write about it and give a presentation.

The paper is called "Utilizing Debug Information to Compact Loops in Large Program Traces." (Sounds exciting doesn't it? ;-) ). Everyone knows that most of the execution of any program is really caused by an enormous amount of repetitive calls to a subset of the methods/functions/subs/whatever that are written in the code. Most of these calls occur within loops structures. That causes a big problem for visualizing traces. Most standard programs will will have millions of calls in the span of a few seconds (Hello World in Java has upwards of 100 000 calls or something rediculous like that!). That's far too big for any standard visualization.

So, what Diver does that is unique is it recognizes that most of the repetitive calls will occur within loops that can be found in the source code of your program. So, it searches your source code (or the source code attached to your jars in Eclipse), and looks for where calls originate from. If they occur in a loop, then only one iteration of the loop is shown at a time.

I ran some experiments on several traced programs, including Eclipse, and found that you can get upwards of an 85% reduction in the size of your visualization (depending on the program that you tracing, and on the visualization--it's particularly good for sequence diagrams) just by compacting loops in this way. That's a pretty significant reduction. The Eclipse JDK was a huge help for this, by the way. It has awesome Java indexing, and a great Java parser that made my work a lot easier.

So, anyway, if you are in the vicinity of Madrid around March 15-18 2010, come by CSMR and say hello.


  1. Was it the JDK or the JDT that was a huge help?

  2. You are right, Ian: that should have said JDT. I think that I may have said "JDK" because I spent a couple of days fighting with the Sun JDK, actually :-).