Guaranteeing instruction fetch behavior with a lookahead instruction fetch engine (LIFE)

Instruction fetch behavior has been shown to be very regular and predictable, even for diverse application areas. In this work, we propose the Lookahead Instruction Fetch Engine (LIFE), which is designed to exploit the regularity present in instruction fetch. The nucleus of LIFE is the Tagless Hit Instruction Cache (TH-IC), a small cache that assists the instruction fetch pipeline stage as it efficiently captures information about both sequential and non-sequential transitions between instructions. TH-IC provides a considerable savings in fetch energy without incurring the performance penalty normally associated with small filter instruction caches. LIFE extends TH-IC by making use of advanced control flow metadata to further improve utilization of fetch-associated structures such as the branch predictor, branch target buffer, and return address stack. These structures are selectively disabled by LIFE when it can be determined that they are unnecessary for the following instruction...

• Type: Conference
• Year: 2009
• Where: LCTRTS
• Authors: Stephen Roderick Hines, Yuval Peress, Peter Gavin, David B. Whalley, Gary S. Tyson
• Keywords: Instruction Fetch, Instruction Fetch Engine, LCTRTS 2009, Lookahead Instruction Fetch, Software Engineering