The Measured Cost of Conservative Garbage Collection University of Colorado at Boulder 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-speciic 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 diierent dynamic storage management algorithms, including domain-speciic allocators; widely-used general-purpose allocators; and a publicly available conservative garbage collection algorithm. Surprisingly, I nd that programmer enhancements often have little eeect on program performance. I also nd that the true cost of conservative garbage collection is not the CPU overhead, but the memory system overhead of the algorithm. I conclude that conservative garbage collection is a promising alternative to explicit storage management and that the performance of conservative collection is likely to be improved in the future. C programmers should now seriously consider using conservative garbage collection instead of malloc/free in programs they write.