Crash Dump Analysis Patterns (Part 243)

In case of parallel memory leak for process heap and .NET heap (or generally with several dynamic memory allocators) we are interested in relative growth to see whether they are interdependent, i.e. managed heap objects have pointers to process heap entries. When we have a set of consecutive memory dumps we can construct a table of heap sizes and plot the graph where the axes represents memory snapshot numbers and total heap size in bytes:

Unfortunately, the relative growth sizes can be disproportionate as the picture above shows. To overcome this, we can normalize size by the lowest corresponding heap size, i.e. Sn/S1:

Still this doesn’t show the absence of correlation if there is no such. We can plot the relative growth, i.e. Sn/Sn-1, n > 1:

The graph shows that there is no obvious correlation between Relative Heap Leaks. Similar graphs can be constructed for relative object distributions.

- Dmitry Vostokov @ + -

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