Analyzing the Impact of Useless Write-Backs on the Endurance and Energy Consumption of PCM Main Memory
Phase Change Memory (PCM) is an emerging technology that has been recently considered as a cost-effective and energy-efficient alternative to traditional DRAM main memory. Due to the high energy consumption of writes and limited number of write cycles, reducing the number of writes to PCM can result in considerable energy savings and endurance improvement. In this paper, the authors introduce the concept of useless write-backs, which occur when a dirty cache line that belongs to a dead memory region is evicted from the cache (a dead region is a memory location that is not used again by a program). Since the evicted data is not used again, the write-back can be safely avoided to improve endurance and energy consumption.