The Measured Cost of Conservative Garbage Collection

Because dynamic memory management is an important part of a large class of computer programs, high-performance algorithms for dynamic memory management have been, and will continue to be, of considerable interest. Experience indicates that for many programs, dynamic storage allocation is so important that programmers feel compelled to write and use their own domain-specific allocators to avoid the overhead of system libraries. Conservative garbage collection has been suggested as an important algorithm for dynamic storage management in C programs. In this paper, I evaluate the costs of different dynamic storage management algorithms, including domain-specific allocators; widely-used general-purpose allocators; and a publicly available conservative garbage collection algorithm. Surprisingly, I find that programmer enhancements often have little effect on program performance. I also find that the true cost of conservative garbage collection is not the CPU overhead, but the memory system ..