Details

Autor(en) / Beteiligte

• Sartor, Jennifer B.
• Heirman, Wim
• Blackburn, Stephen M.
• Eeckhout, Lieven
• McKinley, Kathryn S.

Titel

Cooperative cache scrubbing

Ist Teil von

• 2014 23rd International Conference on Parallel Architecture and Compilation Techniques (PACT), 2014, p.15-26

Ort / Verlag

New York, NY, USA: ACM

Erscheinungsjahr

2014

Link zum Volltext

Quelle

ACM Digital Library Complete

Beschreibungen/Notizen

• Managing the limited resources of power and memory bandwidth while improving performance on multicore hardware is challenging. In particular, more cores demand more memory bandwidth, and multi-threaded applications increasingly stress memory systems, leading to more energy consumption. However, we demonstrate that not all memory traffic is necessary. For modern Java programs, 10 to 60% of DRAM writes are useless, because the data on these lines are dead - the program is guaranteed to never read them again. Furthermore, reading memory only to immediately zero initialize it wastes bandwidth. We propose a software/hardware cooperative solution: the memory manager communicates dead and zero lines with cache scrubbing instructions. We show how scrubbing instructions satisfy MESI cache coherence protocol invariants and demonstrate them in a Java Virtual Machine and multicore simulator. Scrubbing reduces average DRAM traffic by 59%, total DRAM energy by 14%, and dynamic DRAM energy by 57% on a range of configurations. Cooperative software/hardware cache scrubbing reduces memory bandwidth and improves energy efficiency, two critical problems in modern systems.