Comparing Mostly-Copying and Mark-Sweep Conservative Collection

Many high-level language compilers generate C code and then invoke a C compiler for code generation. To date, most of these compilers link the resulting code against a conservative mark-sweep garbage collector in order to reclaim unused memory. We introduce a new collector, MCC, based on an extension of mostly-copying collection. We analyze the various design decisions made in MCC and provide a performance comparisn to the most widely used conservative mark-sweep collector (the Boehm-DemersWeiser collector). Our results show that a good mostlycopying collector can outperform a mature highly-optimized mark-sweep collector when physical memory is large relative to the live data. A surprising result of our analysis is that cache behavior can have a greater impact on overall performance than either collector time or allocation time.