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EETE APR 2014

Ray tracing to replace physical prototypes Nvidia has launched a GPU rendering appliance that dramatically accelerates ray tracing, enabling professional designers to interact with computer models that can replace physical prototypes. The Iray Visual Computing Appliance (VCA) combines hardware and software to greatly accelerate the work of the Iray photorealistic renderer integrated into leading design tools like Dassault Systèmes’ CATIA and Autodesks 3ds Max. Because the appliance is scalable, multiple units can be linked, speeding up by hundreds of times or more the simulation of light bouncing off surfaces in the real world. As a result, car designs and other complex systems can be viewed seamlessly at high visual fidelity from all angles. “Iray VCA lets designers do what they’ve always wanted, to interact with their ideas as if they were already real”, said Jeff Brown, vice president and general manager of Professional Visualisation and Design at Nvidia. “It removes the time-consuming step of building prototypes or rendering out movies, enabling designs to be explored, tweaked and confirmed in real time. Months, even years and enormous cost can be saved in bringing products to market.” Iray VCA uses eight of Nvidia’s most powerful GPUs, each with 12GB of graphics memory, which together deliver 23,040 cores. It has both 10GigE and InfiniBand connections so that rendering clusters of multiple Iray VCAs can be easily built up over time. The Iray cluster-management software dynamically allocates Iray VCAs to meet the workload demands and can be located in an IT center and serve their rendering power on demand, while requiring little or no technical support. The $50,000 Iray VCA systems will be available starting in summer through a global VAR network of certified system integrators. A graphics card turns your PC into a supercomputer for $3000 Nvidia’s latest graphics card provides double precision processing through two Kepler GPUS and 12GB of dedicated frame buffer memory for next-generation 5K and multi-monitor systems. The two K100 chips provide a total of 5,760 processing cores that are tuned to run at the same speed with dynamic power balancing so neither is the performance bottleneck for the 8TFLOPS of processing power. “If you’re in desperate need of a supercomputer that you can fit under your desk, we have just the card for you”, said Jen- Hsun Huang, CEO of Nvidia. NVLink takes on PCI Express Nvidia’s new NVLInk interconnect is directly challenging PCI Express in the data center. PCI Express has been the de facto interconnect for CPUs for a decade, but Nvidia has worked with IBM to use NVLink to provide higher bandwidth links between POWER processors and Nvidia’s Pascal graphics processor in 2016. This will allow systems to scale to exascale (1000 PFLOPS) performance for high performance computing, data analytics and machine learning, says the company. Today’s GPUs are connected to x86-based CPUs through the PCI Express (PCIe) interface, which limits the GPU’s ability to access the CPU memory system and is four- to five-times slower than typical CPU memory systems. PCIe is an even greater bottleneck between the GPU and IBM POWER CPUs, which have more bandwidth than x86 CPUs. The NVLink interface will match the bandwidth of typical CPU memory systems to allow GPUs to access CPU memory at its full bandwidth, operating at data rates 5 to 12 times that of the 8Gbytes/s of the current x16 lane PCIe 3.0. NVLink will provide between 80 and 200 GB/s of bandwidth. The basic building block is an 8-lane differential, dual simplex bidirectional link. The Pascal GPUs will support a number of these links, providing configuration flexibility. The links can be ganged together to form a single GPU to-CPU connection or used individually to create a network of GPU to CPU and GPU to CPU connections. This higher speed will also allow lower energy transfers for the same data rate, reducing the power consumption and heat dissipation in the data center. Nvidia has designed a module to house GPUs based on the Pascal architecture with NVLink that is 30% the size of the standard PCIe boards used for GPUs today. Connectors at the bottom of the Pascal module enable it to be plugged into the motherboard, improving system design and signal integrity. Because of memory system differences – GPUs have fast but small memories, and CPUs have large but slow memories – accelerated computing applications typically move data from the network or disk storage to CPU memory, and then copy the data to GPU memory before it can be crunched by the GPU. With NVLink, the data moves between the CPU memory and GPU memory at much faster speeds, making GPU-accelerated applications run much faster. Nvidia sees this as unlocking the potential of unified memory so that programmers can treat the CPU and GPU memories as one block of memory and not worry whether the data sits in the CPU’s or GPU’s memory. Although Nvidia says future GPUs will continue to support PCIe (as above), NVLink will be used to link CPUs and networks of GPUs. As an industry standard, PCI Express has also been off many challengers over the years. PCIe 4.0 proposes a 16Gtransfers/s bit rate, double today’s PCIe 3.0 specification, while preserving compatibility with software and mechanical interfaces and power envelope. One of the main factors in the wide adoption of the PCIe architecture is its sensitivity to high-volume manufacturing capabilities and materials such as FR4 boards and low-cost connectors, which will be key for PC, tablet and embedded designs that are not the target for NVLink, although it is expected to be used in Intel’s SkyLake and Knight’s Landing server chips with DDR4 memory in late 2015. The final PCIe 4.0 specifications, including form factor specification updates, are expected to be available in late 2015 says the PCI special interest group. 14 Electronic Engineering Times Europe April 2014 www.electronics-eetimes.com


EETE APR 2014
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