POSTER: pmAddr - a Persistent Memory Centric Computing Architecture

Traditional Processor-centric computing architectures do not scale-out well, because servers do not share their local main memories. To bypass this architectural limitation, programmers place their shared state on shared storage. But since Storage is slow (many hundreds of microseconds), they speed performance by duplicating the shared state to the compute nodes and have a complex coherent protocols to try keep all copies in sync. In recent years, Memory-centric architectures were proposed as an alternative. In memory-centric architectures the shared state is placed on a shared memory pool that can be accessed with extreme low latency. Good memory-centric architectures should also be elastic, reliable, load balanced, cheaper than DRAM, thinly provisioned and support multi-tenancy. We present an industrial shared memory solution with all these features. As shown in Figure 1, it is comprised of: 1) a scale-out persistent memory (PM) pool, 2) random-access client-side libraries, 3) a control plane and 4) RDMA fabric. Scale-out application owners use a library called pmAddr, to allocate or connect to a shared logical address space. The client library hides most of the complexity. It communicates with the relevant Data Server (DS) using RDMA and only communicates with the control plane when it does not know which DS holds the relevant memory region, or when its speculative destination turned out to be incorrect.