Recent advances in software engineering, such as graphical user interfaces and object-oriented programming, have caused applications to become more memory intensive. These applications tend to allocate dynamic memory prolifically. Moreover, automatic dynamic memory reclamation (garbage collection, GC) has become a popular feature in modern programming languages such as Java. As a result, the time consumed by dynamic storage management can be up to one-third of the program execution time. The Dynamic Memory Management Unit (DMMU), a special-purpose hardware mechanism based on bitmaps and combinational logic can greatly diminish this overhead. The preliminary results show that the hit ratio for 2 Kbits and 8 Kbits buffer range from 84-99% and 95-99%, respectively. The hardware complexity of the proposed scheme is O(n), where n is the size of the bit-vector. For a design with 20K gates and 97% miss rate, the overall speedup can be as high as 1.41. This proposal calls for the integration of this hardware unit into SMP systems, which would allow concurrent garbage collection in multithreaded-multiprocessors environments. This can speed up the performance of server applications written in Object-oriented languages such as C++ and Java. Additionally, this proposal also calls for the study of garbage collection triggering points. The preliminary study indicates that time-based triggering point may yield higher garbage collection efficiency than the traditional space-based approach.
