Investigating a SoftCache via Dynamic Rewriting

... embedded devices to have the benefits of a memory hierarchy without the hardware costs. A software cache replaces the hardware cache/MMU mechanisms of the embedded system with software management of on-chip RAM using a network server as the backing store. The bulk of the software complexity is placed on the server so that the embedded system contains only the application's current working set and a small runtime system invoked on cache misses. We present a design and implementation of instruction caching using an ARM-based embedded system and a separate server and detail the issues discovered. We show that the software cache succeeds at discovering the small working set of several test applications for a reduction of 7 to 14X of the original application code. Further, we show that our software overhead remains small for typical functions in embedded applications. Finally, we discuss the implications of software caching for dynamic optimization, for power savings and for hardware design