Dynamic Capacity-Speed Tradeoffs in SMT Processor Caches

Caches are designed to provide the best tradeoff between access speed and capacity for a set of target applications. Unfortunately, different applications, and even different phases within the same application, may require a different capacity-speed tradeoff. This problem is exacerbated in a Simultaneous Multi-Threaded (SMT) processor where the optimal cache design may vary drastically with the number of running threads and their characteristics. We propose to make this capacity-speed cache tradeoff dynamic within an SMT core. We extend a previously proposed globally asynchronous, locally synchronous (GALS) processor core with multi-threaded support, and implement dynamically resizable instruction and data caches. As the number of threads and their characteristics change, these adaptive caches automatically adjust from small sizes with fast access times to higher capacity configurations. While the former is more performance-optimal when the core runs a single thread, or a dual-thread...

• Type: Conference
• Year: 2007
• Where: HIPEAC
• Authors: Sonia López, Steve Dropsho, David H. Albonesi, Oscar Garnica, Juan Lanchares
• Keywords: Cache, Capacity-speed Cache Tradeoff, HIPEAC 2007, Optimal Cache Design, System Software