The Parallel Persistent Memory Model
The Parallel Persistent Memory Model
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DOI：
10.1145/3210377.3210381
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发表时间：
2018-05
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影响因子：
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通讯作者：
G. Blelloch;Phillip B. Gibbons;Yan Gu;Charles McGuffey;Julian Shun
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作者：
G. Blelloch;Phillip B. Gibbons;Yan Gu;Charles McGuffey;Julian Shun
我们考虑一个并行的计算模型，由P处理器组成的并行持久存储器模型，每个模型都具有有限大小的局部替代内存，并共享一个较大的持久存储器。概率），并且可能重新启动。它们可以在缓存线的粒度上访问，并且具有生存功率的能力，这进一步观察到，在大型平行系统中，处理器的失败及其caches并不罕见。使用将计算分解为胶囊的方法，每个处理器可以安全地运行单程版本。预期的因素开销。多处理器版本，我们描述了如何在模型中实现工作偷窃调度程序，以便使用处理器重新启动，并在处理器中处理两个软性故障，并为任何多读福克斯（MultineReaded Fork）处理。 - 加入无种族的计算，免费读取冲突，并且在没有故障的情况下具有W工作，D的深度和C最大胶囊工作，调度程序可以保证在$ołefft的型号上限制的时间（\ fracw p_a + \ fracdp p_a left只$是在模型中成功的持久内存访问之间的处理器故障，并且使用提出的方法，我们为并行前缀总和，合并，分类和矩阵乘，开发了有效的算法。
We consider a parallel computational model, the Parallel Persistent Memory model, comprised of P processors, each with a fast local ephemeral memory of limited size, and sharing a large persistent memory. The model allows for each processor to fault at any time (with bounded probability), and possibly restart. When a processor faults, all of its state and local ephemeral memory is lost, but the persistent memory remains. This model is motivated by upcoming non-volatile memories that are nearly as fast as existing random access memory, are accessible at the granularity of cache lines, and have the capability of surviving power outages. It is further motivated by the observation that in large parallel systems, failure of processors and their caches is not unusual. We present several results for the model, using an approach that breaks a computation into capsules, each of which can be safely run multiple times. For the single-processor version we describe how to simulate any program in the RAM, the external memory model, or the ideal-cache model with an expected constant factor overhead. For the multiprocessor version we describe how to efficiently implement a work-stealing scheduler within the model such that it handles both soft faults, with a processor restarting, and hard faults, with a processor permanently failing. For any multithreaded fork-join computation that is race free, write-after-read conflict free and has W work, D depth, and C maximum capsule work in the absence of faults, the scheduler guarantees a time bound on the model of $Ołeft(\fracW P_A + \fracDP P_A łeftłceilłog_1/(C\f) W\right\rceil\right)$ in expectation, where P is the maximum number of processors, $P_A$ is the average number, and $\faultprob łeq 1/(2C)$ is the probability a processor faults between successive persistent memory accesses. Within the model, and using the proposed methods, we develop efficient algorithms for parallel prefix sums, merging, sorting, and matrix multiply.