the Engineers' Guide to VME, VPX & VXS 2013 - Subscribe

More documents

Recommendations

Info

SPECIAL FEATURE Bringing HPC Technology to Mil-Aero, Embedded Deployment Embedded HPEC systems are following the commercial HPC trend towards Intel x86 architectures running Linux, but deployed on VITA’s rugged OpenVPX form factor with RapidIO interconnect fabrics. By Eran Strod, System Architect, Curtiss-Wright Controls Defense Solutions The five hundred of the fastest computers in the world, based on the Linpack benchmark, are featured on a website called top500.org. Recently, 91% of the commercial high-performance computing (HPC) systems on the list were running Linux, nearly half (44%) were using Ethernet and over 80% were using an x86 architecture CPU. These systems are used in scientific, complex simulation, and many other computationally intensive applications. It’s a fair bet that these would be the architectures that sensor systems like high-end radar, SIGINT and other sensor integrators would be using if their applications requirements were not SWaP- and cost-constrained. In contrast to these “big iron” systems, for many years embedded vendors and system integrators built large, distributed systems around niche-oriented architectures such as PowerPC, real-time operating systems, and the not-yet-mainstream RapidIO serial fabric. Sensor modes developed for one platform could not be used on any other. Software was platform-specific and was difficult to port and maintain. This constrained innovation. Different platforms could not talk to each other so data sharing was difficult, resulting in lost opportunities to take advantage of actionable information. But Intel’s investment in AVX changed that. Advanced Vector Extensions (AVX) is an extension to the x86 instruction set architecture that makes the Single Instruction Multiple Data (SIMD) x86 engine suitable for floating point-intensive calculations in multimedia, scientific and financial applications. In short: Intel-based CPUs are more than suitable for high-speed, floating point intensive calculations. As well, the OpenFabrics Alliance has created open source software that, along with development by Curtiss-Wright, allows interfacing RDMA-based Ethernet layers to the very common Figure 1: RapidIO enables a cross-platform ecosystem composed of various CPU/GPU vendors, software, and sensors. RapidIO-based embedded boards deployed in many SWaP-constrained sensor platforms. HPEC is Embedded HPC With this new-found performance, the large node parallel computing systems that are specifically oriented to sensor computing are moving away from PowerPC to Intel. This gives the application developer access to a broad software ecosystem and opens up a whole new set of possibilities for open architecture development. The shift to Intel CPUs allows sensor computing architectures to more easily use Linux. While it’s true that Linux practically runs on every processor architecture known (and probably some unknown), the marriage of Intel and Linux provides the most seamless path to adopting software components developed for HPC. The vast majority of HPC systems run Linux and Intel, and the majority of open source projects also focus on this architecture. With Linux/Intel as the basis of the OpenVPX computing standard, back-end sensor processing that needs to be able to scale to many nodes can take advantage of commercial HPC’s software ecosystem (Figure 1). 24 Engineers’ Guide to VME, VPX & VXS 2013
The process of adapting HPC technologies to the embedded space has recently been described as high-performance embedded computing (HPEC). Several vendors in COTS computing, including Curtiss- Wright, use the term HPEC to mean embedded HPC. Just as HPC is synonymous with the historical term “supercomputing,” HPEC systems are the SWaP-constrained variant of supercomputers. In the defense computing market, the highest performing OpenVPX systems, from vendors like Curtiss-Wright, fit 28 Intel CPUs (112 cores) in a 16-slot chassis, interconnected with a 224 GB/sec dualstar system fabric (Figure 2). But it’s not only about CPUs, buses and interconnects. HPEC is about being able to run the same software that is used in HPC. Fabric Discontinuity – Software Continuity HPC is dominated by Ethernet and InfiniBand, while HPEC 6U OpenVPX computing has been and continues to be dominated by RapidIO. This apparent discontinuity has been one of the major roadblocks to bringing HPC technologies to the HPEC world as the fabric has traditionally had a major impact on software architecture. The first thing to consider is why stick with RapidIO in the face of other reasonably good options? The answer is simple: RapidIO dominates telecommunications DSP computing which faces many of the same constraints as military DSP. Even better, RapidIO is backed by a volume commercial market. IDT, the leading RapidIO switch vendor, just announced that they have shipped 2.5 million RapidIO switches. RapidIO has a dominant position in the DSP processing that is essential to 4G and 3G wireless base stations. RapidIO has captured virtually 100% of the 3G market in China, the fastest growing telecom market. To put it another way, when you talk on your cell phone, there is something like a 90% chance that the bits that represent your voice are at some point transmitted between two DSP processors over a RapidIO link. There are a number of reasons why RapidIO makes sense in the context of HPEC OpenVPX computing: saving SWaP and cost. performance choice in HPC, it is a point technology in OpenVPX HPEC. Unlike Figure 2: Curtiss-Wright showcasing 224GB/s dual-star fabric with 28 Intel CPUs (112 cores) in a mere 16-slot chassis. SPECIAL FEATURE alternatives such as Ethernet and RapidIO, InfiniBand is not anticipated (per simulation) to run reliably at 10 GHz over existing OpenVPX technology. It will require a connector change which is a fairly involved and slow-moving process for an organization like VITA. There were two major challenges in getting RapidIO working in the Intel environment. The first was a classic interconnect problem. PowerPC processors supported RapidIO natively, but Intel did not, so a bridge was needed. The IDT Tsi721 provided this critical piece of technology. The Tsi721 converts from PCIe to RapidIO and vice versa and provides full line rate bridging at 20 Gbaud. Using the Tsi721 designers can develop heterogeneous systems that leverage the peer to peer networking performance of RapidIO while at the same time using multiprocessor clusters that may only be PCIe enabled. Using the Tsi721, applications that require large amounts of data transferred efficiently without processor involvement can be executed using the full line rate block DMA+Messaging engines of the Tsi721. The second major challenge related to RapidIO was software. RapidIO isn’t used in HPC so it doesn’t run the same software as those large cluster-based systems in the top500 that use fabrics like Ethernet and InfiniBand. InfiniBand vendors encountered these same market constraints while trying to grow beyond their niche. It’s hard to “fight” Ethernet. However, Ethernet wasn’t appropriate for the highest performance HPC systems because of the CPU and/or silicon overhead associated with TCP offload. The answer came in the form of new protocols and new software. Open Fabric Alliance The OpenFabrics Alliance (OFA) was formed to promote Remote Direct Memory Acess (RDMA) functionality that allows Ethernet silicon to move packets from the memory of one compute node to the memory of another with very little CPU intervention. There are competing protocols to do this, but wisely, the OFA created a unified software layer called OFED which is supported by Intel, Chelseo, Mellanox and the other members of the Ethernet RDMA ecosystem. OFED is used in business, research and scientific environments that require highly efficient networks, storage connectivity and parallel computing. The OpenFabrics Enterprise Distribution (OFED) is open-source software for RDMA and kernel bypass applications. One of the things that traditionally slowed Ethernet down and wasted the CPU was the need to copy a packet payload numerous times before it was shipped out the Ethernet interface (Figure 3). RDMA has eliminated www.eecatalog.com/vme 25
Page 1 and 2: Engineers’ Guide to VME, VPX & VX
Page 3 and 4: TAKE T TAKE YOUR YO YOUR R VIRTUAL
Page 5 and 6: The only compact, rugged chassis of
Page 8 and 9: SPECIAL FEATURE VME’s Long From D
Page 10 and 11: SPECIAL FEATURE We are also in the
Page 14 and 15: Advertorial 3U VPX Solutions from E
Page 16: SPECIAL FEATURE VPX Backplanes Go O
Page 19 and 20: Table 1: Notional VITA 65 Channel G
Page 21 and 22: Also supported is VITA 48 REDI (Rug
Page 23 and 24: Tackling the Challenge of Building
Page 25: Figure 4: Tecnobit special chassis
Page 29 and 30: SPECIAL FEATURE www.eecatalog.com/v
Page 31 and 32: intended message. To get past those
Page 33 and 34: Test and Analysis Teledyne LeCroy
Page 35 and 36: CPU or Single Board Computers QorIQ
Page 37 and 38: CPU or Single Board Computers 3300G
Page 39 and 40: Data Aquisition Model 53720 3-Chann
Page 41 and 42: Enclosures “Mupac” 760 Small Fo
Page 43 and 44: 2363 2 3 5-W_AeC1 A 3 TAKE Flight!

the Engineers' Guide to VME, VPX & VXS 2013 - Subscribe

Create successful ePaper yourself

Delete template?

Save as template?