ChargeCache: Reducing DRAM Latency by Exploiting Row Access LocalityProceedings of the 22nd International Symposium on High-Performance Computer Architecture (HPCA), Barcelona, Spain, March 2016.
Hasan Hassan†*, Gennady Pekhimenko†, Nandita Vijaykumar† Vivek Seshadri†, Donghyuk Lee†, Oguz Ergin*, Onur Mutlu†
†Carnegie Mellon University
* TOBB University of Economics & Technology
DRAM latency continues to be a critical bottleneck for system performance. In this work, we develop a low-cost mechanism, called ChargeCache, that enables faster access to recentlyaccessed rows in DRAM, with no modifications to DRAM chips. Our mechanism is based on the key observation that a recently-accessed row has more charge and thus the following access to the same row can be performed faster. To exploit this observation, we propose to track the addresses of recently-accessed rows in a table in the memory controller. If a later DRAM request hits in that table, the memory controller uses lower timing parameters, leading to reduced DRAM latency. Row addresses are removed from the table after a specified duration to ensure rows that have leaked too much charge are not accessed with lower latency. We evaluate ChargeCache on a wide variety of workloads and show that it provides significant performance and energy benefits for both single-core and multi-core systems.
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