Introducing the heap profile manager

Well-well, it’s been almost two weeks since the last release, so I decided to show you the beginnings of the heap profile viewing application. After thinking about the alternatives I decided to follow in the steps of others who make core tools and use gtk2hs for the interface. Since I had a working grapher in OpenGL, it was also straightforward to keep it. I started out as a complete beginner in gtk2hs last week, and it proved to be one of the smoothest library learning experiences so far. Even getting several OpenGL drawing areas to work simultaneously went without a hitch. The UI started out as something more complex, but after some experimentation I arrived at the present design:

You can load several graphs in each column (note that multiple selection is enabled in the file open dialog), and move them left and right between columns as you wish. Columns can also be created and destroyed at will. This initial version doesn’t have any more interaction, e.g. you cannot zoom in on areas you’re interested in. Consequently, graphs with an occasional high spike can be unpleasant to look at, as illustrated by the example on the right.

The next step is obviously to add the features that make comparison easier, like displaying scales, displaying identical cost centres with identical colours, adding zooming and panning, comparing a given cost centre from separate runs on the same graph and so on. Also, the profile loader could be probably speeded up a bit by not building a map from times to samples if we convert it into a list anyway.

If all this works okay, I can also add some export plugins (e.g. ps and svg) to finally retire hp2ps.

Oh, the button next to the left arrow doesn’t do anything yet.