Refresh dodging

Abstract

The emerging problem of 3-D stacked DRAM is hot spots over $85^\circ C$ which induces twice-frequent refresh called extended temperature mode deteriorating the performance and power consumption of DRAM. Proposed thermal spreading scheduler prevents the intensification of hot spots by granting priority to the requests whose influence on peak temperature are least critical. This scheduler spreads heat of hot spots and shortens the duration of extended temperature mode, thereby total refresh counts decreased dramatically without any change on DRAM. Experi-ment results show 27.1% reduction of extended temperature mode duration, 19.3% reduction of refresh power consumption without degradation of read/write latency.