N. Papandreou, E. Bougioukou, A. Prodromakis, N. Toulgaridis, T. Antonakopoulos , U. Egger, H. Pozidis, E. Eleftheriou:

Phase Change Memory Access in OpenPOWER Systems using CAPI

The OpenPower Summit Europe 2016, Barcelona, Spain, October 2016.

Abstract: Novel forms of storage class memory (SCM), such as phase change memory (PCM), promise low latency and small granularity of read/write (R/W) access and at the same time they offer high endurance and storage density. These characteristics make them highly desirable for high capacity memory applications such as in-memory databases and in-memory processing. In this work we demonstrate a PCM-based memory sub-system attached to a POWER8 processor via CAPI. Our platform consists of various OpenPOWER servers (IBM S824L, Tyan Palmetto) equipped with CAPI enabled FPGA cards (Alpha-Data) and custom non-volatile DIMMs made of PCM chips (128Mb legacy Micron parts). By leveraging the small R/W access granularity of PCM technology and the efficiency of the CAPI protocol, we demonstrate 128 byte R/W operations at very low latency. In this talk, we will give a brief introduction to phase change memory as the top contender for realizing storage class memory. In addition, we will describe the architecture of our prototype system and present the basic FPGA architecture of our CAPI-based phase change memory controller. Moreover, we will demonstrate latency and performance measurements using our custom-made PCM DIMMs as well as custom HW logic that emulates future PCM technology.

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