Short-term hp2any plans

I haven’t written for a while, because I was distracted by other activities for a few days. I have no code or pretty pictures to show this time, just a few words on what I intend to do next.

This week’s milestone is a working network protocol for the grapher that can also be used by other tools, e.g. to monitor the heap of a remote application. Next week will be mainly about improving this feature and implementing some more functionality in the grapher that will hopefully make it a more useful tool. The rest of July shall be dedicated to the history manager.

You can draw your own graphs now!

Sorry, no pictures this time, there’s nothing new to show. However, you can play with the grapher now, so go grab the source from the repository. The details of the update are in the commits. First I wanted to polish the grapher a bit more before this release, but I got held down by more duties than I had expected, and I figured it’s only for everyone’s benefit to start exercising the code as early as possible. It also gives you something to provide feedback on.

There are two main features I’ll add to this grapher: zooming-panning and a socket based remote control interface that allows other programs to use it as a display. It might even become a generic grapher that’s attached to the profiler output through some minimal glue code that also uses the remote interface. The same glue code could actually be used to make profiling output available over the network to anyone interested, sharing the protocol of the grapher.

It’s also time to start thinking about the history manager (I’m reluctant to call it a framework, however fancy it would sound ;). At this point, the most important question is which windowing toolkit to use. I have already collected some vague ideas on the project wiki, and I’d need some advice on this.

More colourful graphs

In order to make it easier to compare cost centres, I added a cumulative view that works the same way as hp2ps. Generating appropriate colours is tricky when you don’t know the data in advance, but the result is at least satisfactory for the time being. Hovering over an area causes the name of the respective cost centre to be displayed in the top left corner, as illustrated by the following screenshots:



The vertical magnification of the graph depends on the last 50 samples, so a huge spike will squeeze the diagram only for a limited amount of time, as you can see on the screenshots too.

Of course, the line graphs are also available, but the two can’t be toggled during a single run yet, so here’s a picture from another one (the lines are broken at places, because the Gnome screenshotter can’t seem to keep up with the animation):



What’s next? The first thing to do is to optimise graphing, because everything is recalculated for each frame in the current snapshot, and it doesn’t take long for the visualiser to stress the CPU more than the program we’re profiling... Pushing everything into display lists should take care of that. The next step is to add the means to stop the animation and look around in the graph, and also the option to display only the last portion while animating the graph.

When the grapher works fine as a standalone application, I’ll start extending it with remote control capabilities as outlined on the project wiki.

The first graphs

Well, after a few days of other distractions I got back to hp2any and implemented a simplistic graphing utility on top of the core library. Here is the first test run featuring a little game I’m working on in my similarly little spare time:



Oops, of course I forgot about the evils of laziness right away... I removed some debug text, but still calculate the values that would be displayed, which are therefore never evaluated and hold on to various big structures from every past frame. The situation is much better after adding an exclamation mark at the right spot:



There’s no public code yet, but I hope to get it in a much better shape in a few days.