Toward Large-Scale Shared Memory Multiprocessing
Toward Large-Scale Shared Memory Multiprocessing
复制标题
迈向大规模共享内存多处理
DOI：
10.1007/978-1-4615-3604-8_15
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
W. Zwaenepoel
中科院分区：
文献类型：
--
作者：
J. Bennett;J. Carter;W. Zwaenepoel
我们目前正在研究两种不同的可伸缩共享内存方法：Munin，一个完全由软件实现的分布式共享内存(DSM)系统；以及Willow，一个真正的共享内存多处理器，具有广泛的硬件可伸缩性支持。Munin允许为共享内存多处理器编写的并行程序在分布式内存多处理器上高效执行。与只提供单一存储器一致性机制的现有DSM系统不同，Munin提供多个一致性协议，基于对该对象的预期访问模式将协议与数据对象匹配。我们称这种方法为特定类型的连贯。Munin还采用了一种宽松的一致性模型来屏蔽网络延迟，并最大限度地减少保持内存一致性所需的消息数量。Willow的目标是成为真正的共享内存多处理器，提供能够支持一千多个商业微处理器的内存容量和性能。这些处理器以集群方式排列，具有多级缓存、I/O、同步和内存层次结构。Willow与其他共享内存多处理器的不同之处在于分层的内存组织，它显著降低了闭包对缓存层次结构的影响，并利用了局部梯度。Willow还提供了对自适应缓存一致性的支持，这是一种类似于Munin的特定类型一致性的方法，通过该方法，基于对存储在该行中的数据的预期或观察访问行为来选择用于管理每个缓存行的一致性协议。Munin的实施正在进行中；我们仍在设计Willow。
We are currently investigating two different approaches to scalable shared memory: Munin, a distributed shared memory (DSM) system implemented entirely in software, and Willow, a true shared memory multiprocessor with extensive hardware support for scalability. Munin allows parallel programs written for shared memory multiprocessors to be executed efficiently on distributed memory multiprocessors. Unlike existing DSM systems, which only provide a single mechanism for memory consistency, Munin provides multiple consistency protocols, matching protocol to data object based on the expected pattern of accesses to that object. We call this approachtype-specific coherence. Munin also employs a relaxed consistency model to mask network latency and to minimize the number of messages required for keeping memory consistent. Willow is intended to be a true shared memory multiprocessor, providing memory capacity and performance capable of supporting over a thousand commercial microprocessors. These processors are arranged in cluster fashion, with a multi-level cache, I/O, synchronization, and memory hierarchy. Willow is distinguished from other shared memory multiprocessors by a layered memory organization that significantly reduces the impact ofinclusionon the cache hierarchy and that exploits locality gradients. Willow also provides support foradaptive cache coherence, an approach similar to Munin’s type-specific coherence, whereby the consistency protocol used to manage each cache line is selected based on the expected or observed access behavior for the data stored in that line. Implementation of Munin is in progress; we are still designing Willow.