Heap Tracing

The Collector records tracing data for calls to the memory allocation and deallocation functions malloc, realloc, memalign, and free by interposing on these functions. If your program bypasses these functions to allocate memory, tracing data is not recorded. Tracing data is not recorded for Java memory management, which uses a different mechanism.

The functions that are traced could be loaded from any of a number of libraries. The data that you see in the Performance Analyzer might depend on the library from which a given function is loaded.

If a program makes a large number of calls to the traced functions in a short space of time, the time taken to execute the program can be significantly lengthened. The extra time is used in recording the tracing data.