XK7 is a

supercomputing A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second (FLOPS) instead of million instructions ...

platform, produced by

Cray Cray Inc., a subsidiary of Hewlett Packard Enterprise, is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed ...

, launched on October 29, 2012. XK7 is the second platform from Cray to use a combination of

central processing unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

s ("CPUs") and

graphical processing unit A graphics processing unit (GPU) is a specialized electronic circuit designed to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobil ...

s ("GPUs") for computing; the hybrid architecture requires a different approach to programming to that of CPU-only supercomputers. Laboratories that host XK7 machines host workshops to train researchers in the new programming languages needed for XK7 machines. The platform is used in Titan, the world's second fastest supercomputer in the November 2013 list as ranked by the

TOP500 The TOP500 project ranks and details the 500 most powerful non-distributed computing, distributed computer systems in the world. The project was started in 1993 and publishes an updated list of the supercomputers twice a year. The first of these ...

organization. Other customers include the

Swiss National Supercomputing Centre Swiss may refer to: * the adjectival form of Switzerland *Swiss people Places *Swiss, Missouri *Swiss, North Carolina *Swiss, West Virginia *Swiss, Wisconsin Other uses *Swiss-system tournament, in various games and sports *Swiss International A ...

which has a 272 node machine and

Blue Waters Blue Waters was a petascale supercomputer operated by the National Center for Supercomputing Applications (NCSA) at the University of Illinois at Urbana-Champaign. On August 8, 2007, the National Science Board approved a resolution which authori ...

has a machine that has

Cray XE6 The Cray XE6 (codename during development: ''Baker)'' made by Cray is an enhanced version of the Cray XT6 supercomputer, officially announced on 25 May 2010. The XE6 uses the same computer blade found in the XT6, with eight- or 12-core Opteron 61 ...

and XK7 nodes that performs at approximately 1 petaFLOPS (10¹⁵

floating-point operations per second In computing, floating point operations per second (FLOPS, flops or flop/s) is a measure of computer performance, useful in fields of scientific computations that require floating-point calculations. For such cases, it is a more accurate mea ...

Overview

XK7 is scalable up to 500 cabinets, each contains 24

blades A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are to be used on. Historic ...

and each blade contains 4 nodes (1 CPU and 1 GPU per node). The CPUs available are of the 16-core AMD Opteron 6200 ''Interlagos'' series and the GPUs are of the Nvidia Tesla K20 ''Kepler'' series. Each CPU can be paired with either 16 or 32 GB of

error-correcting code memory Error correction code memory (ECC memory) is a type of computer data storage that uses an error correction code (ECC) to detect and correct n-bit data corruption which occurs in memory. ECC memory is used in most computers where data corruption c ...

(ECC) while the GPUs have either 5 or 6 GB of ECC memory depending on the model of GPU used. The nodes communicate with each other via the Gemini Interconnect; each Gemini chip services 2 nodes with a capacity of 160 GB/s. Depending on the components used, a full cabinet will consume between 45 and 54.1 kW of electricity which is converted into heat; thus the cabinets need cooling, either by air or water. XK7 based machines run the Cray Linux Environment which incorporates

SUSE Linux Enterprise Server SUSE Linux Enterprise (often abbreviated to SLE) is a Linux-based operating system developed by SUSE. It is available in two editions, suffixed with Server (SLES) for servers and mainframes, and Desktop (SLED) for workstations and desktop compu ...

. Code to run on an XK7 machine can be written in a range of programming languages. The hybrid architecture requires different programming to conventional CPU-only supercomputers;

Oak Ridge National Laboratory Oak Ridge National Laboratory (ORNL) is a U.S. multiprogram science and technology national laboratory sponsored by the U.S. Department of Energy (DOE) and administered, managed, and operated by UT–Battelle as a federally funded research and ...

and the

hold workshops to educate researchers on the new programming approach.

Usage

The XK7 platform was announced on October 29, 2012 to coincide with the completion of Titan at Oak Ridge National Laboratory (ORNL). Titan has 18,688 XK7 nodes, each containing an Opteron 6274 CPU with 32 GB of memory and a K20X GPU with 6 GB. The computer has a theoretical peak performance of 27.1 petaFLOPS but in the LINPACK benchmark used by the TOP500 organisation to rank supercomputers it performed at 17.59 petaFLOPS, enough to take first place on the November 2012 list. Titan uses 8.2 MW of electricity and is third on the

Green500 The Green500 is a biannual An anniversary is the date on which an event took place or an institution was founded in a previous year, and may also refer to the commemoration or celebration of that event. The word was first used for Catholic f ...

list which ranks supercomputers by their energy efficiency. The

National Center for Supercomputing Applications The National Center for Supercomputing Applications (NCSA) is a state-federal partnership to develop and deploy national-scale computer infrastructure that advances research, science and engineering based in the United States. NCSA operates as a ...

(NCSA) in Illinois has a machine,

, using a combination of

and XK7 nodes. The machine has 3072 XK7 nodes and 22,752 XE6 nodes. Each XE6 node has two Opteron 6276 and 32 GB of memory per CPU. The XK7 nodes also have Opteron 6276 CPUs with 32 GB of memory and a K20X GPU with 6 GB. Blue Waters has performed at over 1 petaFLOPS in benchmarks; however, the project managers do not believe in the relevance of the LINPACK benchmark used by the TOP500 organisation and therefore did not submit a benchmark test for ranking. The Swiss National Supercomputing Centre (CSCS) machine named Todi was upgraded to XK7 on October 22, 2012. Todi has 272 nodes with Opteron 6272 CPUs with 32 GB of memory and a K20X GPU with 6 GB. Todi has a theoretical peak performance of 393 teraFLOPS and performed at 274 teraFLOPS in the November 2012 TOP500 list taking 91st place. Todi consumes 122 kW and is ranked fourth, one behind Titan, on the November 2012 Green500 list.

References

{{Cray computers XK7 X86 supercomputers