Get Ready for Intel’s Knights Landing (KNL) – 3 papers

Automatic Vectorization with Intel AVX-512 Instructions in KNL

In this document, we focus on the new vector instruction set introduced in Knights Landing processors, Intel® Advanced Vector Extensions 512 (Intel® AVX-512). The discussion includes:

• Introduction to vector instructions in general,
• The structure and specifics of AVX-512, and
• Practical usage tips: checking if a processor has support for various features, compilation process and compiler arguments, pros and cons of explicit and automatic vectorization, using the Intel® C++ Compiler and the GNU Compiler Collection.

Clustering Modes in Knights Landing Processors

We start a discussion of what types of applications benefit from the clustering modes and why clustering modes help these applications. After that we cover the specifics of the available cluster modes: all-to-all, quadrant, hemisphere, SNC-4 and SNC-2. Finally, we discuss how to make the application NUMA-aware for use in SNC modes. In this context, we give recipes for nested OpenMP and hybrid MPI+OpenMP approaches combined with first-touch allocation policy, numactl tool and memkind library.

MCDRAM as High-Bandwidth Memory (HBM) in KNL Processors

In this document we discuss the on-package high-bandwidth memory (HBM) based on the multi-channel dynamic random access memory (MCDRAM) technology:

• Three configuration modes of HBM: Flat mode, Cache mode and Hybrid mode
• Utilization of the HBM as addressable memory using two methods: by setting affinity policy with the numactl tool and through the usage of special allocators in the memkind library
• Guidelines for determining the optimal usage model for applications running on bootable Knights Landing.