如何使用堆转储来计算堆碎片化统计信息

Question

有谁知道是否有任何工具可以使用堆转储来计算堆碎片？

Answer 1

I have a tool to visualize the heap (http://bobah.net/d4d/tools/cpp-heapmap) but it consumes the list of {op;address;size} triplets, not a raw heap dump. You can use it to visually estimate how bad the heap is. In some cases it's just enough. It's malloc interceptor would obviously not fit for Java app, but the UI does not care where numbers come from and would display ones from any source.

But let's assume we are able build a heap map from the dump (I'm sure someone will answer here how exactly). The main part of the problem is to calculate fragmentation curve F(s), s - target allocation size. F(s) - the ratio of (total_free_space/s), to number of blocks of size s which can actually be allocated considering particular heap layout.

Once the F(s) is built, one can integrate it in the interval from 1 to S (total heap size) to have a single number representing the heap fragmentation or usage efficiency.

Answer 2

IBM垃圾收集和内存分析器非常适合此类情况，并且是免费的。