Tuesday, July 29, 2008

Space profiler needs profiling

I struggled and failed against the Allegro CL 8 space profiler yesterday. I tried capturing a space profile for some of our software running on Windows. With only five seconds worth of data Allegro CL would chew up 300MB of heap in producing the profile. Needless to say there was nothing meaningful to be had there.

What I really want is to get visibility into which heap data allocated makes it to oldspace. I want to see what's making the image size grow. I'm not getting useful data from the space profiler, and I don't think I possibly could. Time profilers are much more useful in optimization, space profilers can't separate temporary allocations from those that get tenured.