一句话：提出基于 Shapley 值的写入归因与写预算分配方法，实现合并闪存缓存中多工作负载的性能公平。
多工作负载共享同一闪存设备时，如何公平划分设备资源并让各负载对设备磨损的贡献（包括垃圾回收产生的隐藏写入）被公平归因，是一个新问题；当闪存用作缓存/缓冲区时，这直接影响各负载可获得的服务流量与性能。本文首先说明写入归因问题为何非平凡，继而受合作博弈论中 Shapley 值启发提出写入归因技术，并验证其准确、公平且可行。随后将设备在给定时间段内的总允许写入量视为一等资源，提出写预算分配技术，并将上述机制组合成动态寿命管理框架。在真实工作负载上的实验表明，该分配与归因方法能提升合并负载间的性能公平性。
Consolidating multiple workloads on a single flash-based storage device is now a common practice. We identify a new problem related to lifetime management in such settings: how should one partition device resources among consolidated workloads such that their allowed contributions to the device's wear (resulting from their writes including hidden writes due to garbage collection) may be deemed fairly assigned? When flash is used as a cache/buffer, such fairness is important because it impacts what and how much traffic from various workloads may be serviced using flash which in turn affects their performance. We first clarify why the write attribution problem (i.e., which workload contributed how many writes) is non-trivial. We then present a technique for it inspired by the Shapley value, a classical concept from cooperative game theory, and demonstrate that it is accurate, fair, and feasible. We next consider how to treat an overall "write budget" (i.e., total allowable writes during a given time period) for the device as a first-class resource worthy of explicit management. Towards this, we propose a novel write budget allocation technique. Finally, we construct a dynamic lifetime management framework for consolidated devices by putting the above elements together. Our experiments using real-world workloads demonstrate that our write allocation and attribution techniques lead to performance fairness across consolidated workloads.
@inproceedings{paperbot5418,
title = {Fair Write Attribution and Allocation for Consolidated Flash Cache},
author = {Wonil Choi and Bhuvan Urgaonkar and Mahmut Kandemir and Myoungsoo Jung and David Evans},
booktitle = {ASPLOS},
year = {2020},
doi = {10.1145/3373376.3378502}
}