The block-based trace cache

Abstract

The trace cache is a recently proposed solution to achieving high instruction fetch bandwidth by buffering and reusing dynamic instruction traces. This work presents a new block-based trace cache implementation that can achieve higher IPC performance with more efficient storage of traces. Instead of explicitly storing instructions of a trace, pointers to blocks constituting a trace are stored in a much smaller trace table. The block-based trace cache renames fetch addresses at the basic block level and stores aligned blocks in a block cache. Traces are constructed by accessing the replicated block cache using block pointers from the trace table. Performance potential of the blockbased trace cache is quantified and compared with perfect branch prediction and perfect fetch schemes. Comparing to the conventional trace cache, the block-based design can achieve higher IPC, with less impact on cycle time.