IEICE Transactions on Information and Systems
Online ISSN : 1745-1361
Print ISSN : 0916-8532
Special Section on Parallel and Distributed Computing and Networking
A Lightweight Method to Evaluate Effect of Approximate Memory with Hardware Performance Monitors
Soramichi AKIYAMA
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2019 Volume E102.D Issue 12 Pages 2354-2365


The latency and the energy consumption of DRAM are serious concerns because (1) the latency has not improved much for decades and (2) recent machines have huge capacity of main memory. Device-level studies reduce them by shortening the wait time of DRAM internal operations so that they finish fast and consume less energy. Applying these techniques aggressively to achieve approximate memory is a promising direction to further reduce the overhead, given that many data-center applications today are to some extent robust to bit-flips. To advance research on approximate memory, it is required to evaluate its effect to applications so that both researchers and potential users of approximate memory can investigate how it affects realistic applications. However, hardware simulators are too slow to run workloads repeatedly with different parameters. To this end, we propose a lightweight method to evaluate effect of approximate memory. The idea is to count the number of DRAM internal operations that occur to approximate data of applications and calculate the probability of bit-flips based on it, instead of using heavy-weight simulators. The evaluation shows that our system is 3 orders of magnitude faster than cycle accurate simulators, and we also give case studies of evaluating effect of approximate memory to some realistic applications.

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© 2019 The Institute of Electronics, Information and Communication Engineers
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