Cray Logo

blog  facebook  twitter  linkedin  google plus  youtube
HomeSupportCustom EngineeringIndustry SolutionsProgramsAbout Cray
ComputingStorageBig Data
Request Quotespacer
graphic Computing


Software for the Cray XK7 System

Scalable Programming Capabilities

The Cray XK7 supercomputer supports a full range of powerful scalar tools, libraries, compilers, operating system and third-party software.

Programming Environment

Each Cray XK7 system includes a fully integrated Cray programming environment with tools designed to maximize programmer productivity and application scalability and performance. This feature-rich, flexible programming environment facilitates the development of scalable applications. For example, the Cray XK7 supercomputer can use a variety of high performance Fortran, C and C++ compilers and libraries for both x86 and GPU workloads. Available compilers include GPU-enabled PGI, CAPS, PathScale and the Cray Compiler Environment for x86 with support for the ISO Fortran standard (2008) including parallel programming using coarrays, C/C++ and UPC. Available high performance-optimized math libraries include BLAS, FFTs, LAPACK, ScaLAPACK, SuperLU and Cray Scientific and Math Libraries.

Programming Models

Supported parallel programming models include MPI, CUDA, Cray SHMEM™, UPC, Coarray Fortran, OpenMP and OpenACC (for directives-based accelerator programming). The MPI implementation is compliant with the MPI 2.0 standard and is optimized to take advantage of the Gemini interconnect. Cray’s performance and analysis toolkit CrayPat™ allows users to analyze resource utilization throughout their code at scale and eliminate bottleneck and load imbalance issues.

In addition to supporting MPI over the standard programming languages of C, C++ and Fortran, the Gemini interconnect has direct hardware support for partitioned global address space (PGAS) programming models including Unified Parallel C (UPC), Co-Array Fortran and Chapel. Gemini allows remote references to be pipelined in these programming models which can result in orders-of-magnitude performance improvement over library-based message passing models. This feature brings highly scalable performance to communication-intensive, irregular algorithms.

Scalable Software

Cray Linux Environment (CLE)The Cray XK7 system ships with the latest Cray Linux Environment™ (CLE), a suite of high performance software including a SUSE™ Linux-based operating system designed to scale efficiently and run large, complex applications. With highly scalable applications, Compute Node Linux (CNL) runs in Extreme Scalability Mode (ESM), ensuring operating system services do not interfere with application scalability. Real-world applications have proven this optimized design scales to 250,000 cores.

Additionally, the Cray XK7 system provides for tightly integrated, industry-standard batch schedulers, compilers and debuggers. Supported workload managers include Altair PBS Professional®, Moab Adaptive Computing Suite™ and Platform LSF®. Supported compilers include PGI, PathScale, CAPS and Cray. Supported debuggers include TotalView Technologies and Allinea as well as many open source programming tools.


Cray is a joint founding member the OpenACC organization, driving a new directives-based open parallel programming standard enabling scientific and technical programmers to more easily leverage the performance optimization capabilities of hybrid CPU/GPU computing systems. Learn more by visiting

OpenACC V2.0 Reference Guide

The OpenACC® API 2.0



Is OpenACC right for your Code?

What Parts of My Code Are Right for Accelerators?

Case Study – COSMO Atmospheric Model with OpenACC

COSMO Dynamics and Physics Modules Are Accelerated as a Part of HP2C Initiative Using OpenACC

Case Study Applying OpenACC to the CloverLeaf Hydrodynamics Mini-App

Applying OpenACC to the CloverLeaf Hydrodynamics Mini-App