Are Mallocs Free of Fragmentation? (NOT KNOWN IF TALK GIVEN)

Malloc(3) is considered to be a robust building block. However, we found that many malloc implementations suffer from excessive heap fragmentation when used with Hummingbird, a long-running application which stores a large number of fixed-sized and variable-sized objects in dynamic memory. This paper characterizes the dynamic memory activity pattern of Hummingbird and compares the behavior of nine different mallocs when used with Hummingbird. We found that the best malloc caused 9.6% fragmentation (increased heap size above the amount of active memory), while the worst malloc caused a heap overflow.