Using PCI Express for Next Generation Battlefield Applications

Transcription

1 Using PCI Express for the Next Generation Of Using PCI Express for Next Generation Manville Chan, Cornet Technology, Inc. Stephen Moore, PLX Technology Cornet Technology Inc., 6800 Versar Center, Suite 216, Springfield, VA Phone: Fax: Web Site:

2 Using PCI Express for the Next Generation Of Table of Contents OVERVIEW...5 THE CHALLENGE: DESIGNING EMBEDDED SYSTEMS FOR MILITARY PROGRAMS...6 THE CASE FOR PCI EXPRESS...6 COMMUNITY OF SUPPORT...7 HIGH-SPEED AND RELIABLE DATA SHARING CAPABILITIES...7 SUMMARY...9 A QUICK COMPARISON OF SWITCHED SERIAL FABRIC & HIGH-SPEED I/O INTERCONNECT TECHNOLOGIES...10

3 Overview PCI Express, a high-speed peripheral interconnect evolved from the PCI and PCI-X architectures, is widely used in computers, servers, and mobile devices. Established as a standard in 2001, PCI Express commercial implementations hit the market in While PCI Express migrated from the PCI standard, its hardware architecture is considerably different. PCI Express is built around a serial, point-to-point link between two devices, while PCI utilizes a bus-based architecture. This allows higher throughput while reducing pin and trace counts. Yet PCI Express maintains backward compatibility with PCI and PCI-X in the packet level, allowing existing PCI and PCI-X software code to be reused with PCI Express hardware. PCI Express is widely used in the commercial marketplace, as leading chip manufacturers such as Intel were early adopters. However, it hasn t significantly penetrated the military embedded systems market, where PCI and PCI-X are still the predominant interconnect standards utilized for COTS applications. A major barrier to the adoption of PCI Express, by the military, is the limited availability of COTS products that address their technical requirements. Currently, only a handful of vendors manufacture PCI Express compatible products for the military market. For military applications to benefit from PCI Express savings in time and money a greater number of military-focused PCI Express products need to be developed. Encouragingly, the embedded systems industry has been highly supportive of PCI Express. For example, the VMEbus International Trade Association (VITA) has incorporated PCI Express into all the newer high speed I/O interconnect specifications such as VXS and XMC, paving the path for this advantageous new technology to move into military applications. 5

4 The Challenge: Designing Embedded Systems for Military Programs Engineers face many challenges when designing embedded systems equipment for military programs. Due to tight budgets, military embedded systems programs are often required to produce more with less - in less time, with fewer personnel and lower funding. However, the number and complexity of projects continues to increase. Gone are the days when designers had the time and funding to build a system from the ground up with their own bus, interface, platform, hardware and operating system environments. To meet today s design challenges; these system designers must look to Commercial-off-the-Shelf (COTS) products to develop their military solutions. Prior to the high-tech commercial-off-the-shelf revolution, every vendor offered its own products with their own proprietary technologies. Thus products were unable to interface with one another. As the industry matured, vendors began to collaborate and discuss interoperable standards. This gave way to open-standard COTS technologies. Open-standard technologies, give military embedded systems designers a greater number of suppliers guaranteeing more competition in the market place. Ideally, open standards in the embedded community should cover the entire embedded ecosystem - including components, backplanes, boards, intellectual property (IP) and software. However, some standards that claim to be open utilize proprietary ASIC implementations of the interfaces. In addition, vendors or vendor-sponsored associations, unique to those technologies, maintain the associated specifications. To be a truly open standard and extend the technology s benefits, products must have the ability to employ the standard easily. COTS products, which leverage economies of scale, are available to cost effectively address the changing military systems design landscape. Since COTS products are manufactured in higher volumes, their unit cost is less than traditional military solutions. Additionally, by implementing COTSbased solutions the time spent to design an embedded system can be reduced from several months to several weeks. An added benefit using open standards embedded system design is the availability of a larger pool of talented and experienced engineers. The Case for PCI Express Interconnects have experienced their own technology evolution cycle moving from customerspecific proprietary designs to industry developed open standards such as PCI Express and Rapid I/O. Since many systems already use PCI and PCI-X busses, PCI Express provides a natural technology path for next generation military applications. Another driving force behind the adoption of PCI Express is the wide range of available components and the acceptance of PCI Express as a superior platform in general industry. With the numerous advantages offered by PCI Express, the military market is ready for more COTS board-level solutions to be introduced. 6

5 Community of Support A standard should not be considered open unless there is a large community of support. Special interest groups and trade associations such as PCI-SIG and VITA play a crucial role in promoting PCI Express in the military embedded community. PCI-SIG ( is one of the largest, vendor-neutral associations within the computer industry. The primary function of the association is to deliver a stable, straightforward and compatible standard for PCI devices. PCI-SIG spearheaded the development of PCI Express specifications. It is currently working towards a 2.0 version of the base standard which will double the transfer rate to 5 Gbps per link. VITA ( introduced sub-standards for PCI Express under VME Switched Serial (VXS, VITA 41.4) and Serial Mezzanine Card (XMC, VITA 42.3) that extended PCI Express technology into high-speed I/O interconnect for system-area network applications. High-Speed and Reliable Data Sharing Capabilities Signal intelligence applications collect huge amounts of raw data. This data must be input into a processing engine in real-time and the processed data must be disseminated similarly. PCI Express addresses this need for high-speed data transfer. Each lane of PCI Express has a line rate of 2.5 Gbps. It can be scaled to 2, 4, 8, 12, 16, and 32 lanes. With 32 lanes, PCI Express supports a transfer rate of 80 Gbps in each direction. The proposed PCI Express specification doubles the transfer rate to 160 Gbps for x32 lane. PCI Express ensures data integrity with error handling and RAS (reliability, availability, serviceability) features incorporated into each transaction packet. 7

6 Real Time Data Analysis and Dissemination in a Net-Centric System Today, technological decisions can be remarkably complicated. Real-time data analysis and dissemination are increasingly important in a military theatre of operation. For example, the modern military utilizes unmanned aerial vehicles (UAV) to obtain intelligence vital to the completion of critical combat missions. In a combat situation, UAVs are often used to capture data such as photographs, infrared and electronic signatures. These images are analyzed to pinpoint the location of an enemy s military operations. Once a target is defined, the UAV relays a signal to ground missile launchers. For this reason, accurate data imagery and analysis is crucial to a successful operation. If image-processing techniques are not sufficiently intelligent, an operation could potentially misinterpret a civilian site for a military position. In addition, if the information is not disseminated in real-time, the enemy s military operations could shift, closing the strike window. Being a high-speed interconnect, PCI Express supports the channeling of information at a high rate to processing elements. Many of the new, high-speed data acquisition I/O cards utilize PCI Express to enhance throughput. When processing video images or other complicated data in real time, the amount of transmitted data can be significant. The ability to process this type of information is often limited by how quickly it can stream into the compute elements. In such a scenario, PCI Express provides a measurable difference in the ability to utilize data quickly and efficiently. The advent of network-centric warfare initiatives such as Joint Tactical Radio Systems (JTRS) plays a crucial role in technological decisions made by military embedded designers. JTRS fosters the sharing of intelligence among a wide range of military equipment and data centers in government agencies. This enables cross-analysis of data so that the military can identity an enemy more accurately and precisely in a critical combat environment. Networkcentric warfare requires intelligence to be stored and retrieved to/from a massive cross-analysis data repository. By using PCI Express, an embedded sub-system can be linked to other servers in which PCI Express has already been widely available. In a signal intelligence (SIGINT) system, as shown in Figure 1, PCI Express can greatly enhance information processing in the system using the high-speed, full-duplex links. These links operate at a rate of 10 Gbps (2.5 Gbps x 4) in each direction. RF antenna signals are digitalized using a PCI Express VXS digitizer. The digitizer is linked through a meshed configuration to a VXS multi-processing computer. The multi-processing computer system includes two PCI Express XMC sites, allowing processed data to be sent to a data repository via serial FPDP. Figure 1 A Signal Intelligence Application using PCI Express under a Meshed VXS System Architectural Diagram PCI Express Topology Serial FPDP Interface Serial FPDP Interface RF Antenna Signal Signal Conditioner Conditioner Tuner Tuner IF RF Antenna Signal Signal Conditioner Conditioner Tuner Tuner IF Quad Processing Engine PCI - X to PCIe Bridge Root Complex Quad Processing Engine PCI - X to PCIe Bridge PCIe 4x Lane Switch 4x Lane 10Gbps 10Gbps 4x Lane 10Gbps Digitizer PCI - X to PCIe Bridge 4x Lane 10Gbps Digitizer Digitizer PCI - X to PCIe Bridge 5 - Port Switch PCIe Endpoint PCIe Endpoint PCIe Endpoint PCIe Endpoint Serial Serial Sensor Sensor FPDP FPDP Data Data Interface Interface 8

7 Summary Widespread deployment of the PCI Express standard in military applications offers the military a number of benefits. These include significant time and money savings by reducing design and component cost as well as a large pool of talented and knowledgeable PCI-experienced engineers available for staffing embedded system design and development organizations. The unique features of this standard allow the dissemination of data and imagery in real-time. Since PCI Express employs high-speed serial interconnect technology, it supports the transfer of high-speed information into and out of a processing engine providing field commanders with the ability to make critical decisions quickly. In addition, PCI Express is compatible with the recent advent of net-centric warfare, permitting disparate systems to communicate with one another efficiently. This is especially important in a military theatre, where position and strategy are highly fluid. Widespread migration to the PCI Express standard could greatly enhance productivity and reduce design costs for the modern military. The enhanced throughput speeds offered by the standard, the ability to scale performance for years to come, and the advantages available through utilization of open standard technology and COTS products is an added benefit not offered by other solutions. 9

8 Appendix A Quick Comparison of Switched Serial Fabric & High-Speed I/O Interconnect Technologies Fabric Technology Aurora GigE 10 Gig Be Infiniband PCI Express Serial RapidIO Starfabric Standards Org Xilinx IEEE IEEE Infiniband TA PCI-SIG RapidIO TA StarFabric TA Current Spec (Date) SP (June 2004) IEEE 802.3ab (1999) IEEE (Oct. 2004) 1.1 (March 2005) 1.3 (June 2005) Further Specs (Date) VITA 41.5, VITA 42.5, VITA 55 AMC.2, PICMG 2.16, PICMG 3.1, VITA 41.3, VITA 46.6 VITA 46.7 PICMG 3.2, VITA 41.1, VITA 46.8 AMC.1, EXP.0, PICMG 3.4, VITA 41.4, VITA 42.3, VITA 46.4, COMe AMC.4, PICMG 2.18, PICMG 3.5, VITA 41.2, VITA 42.2, VITA 46.3 PICMG 2.17 PICMG 3.3 Microstrip Baud Rate (Gbps/lane/ direction = 4 wires) 1.25 / 2.5 / / 5 / (Gen 1) / 5.0 (Gen 2) 1.25 / 2.5 / Target Applications FPGA interconnect Networking, Medium-speed I/O Networking, High-speed I/O Server interconnect for high-end clustered computing High-speed I/O and chip-to-chip communication DSP/CPU intercommunication and backplane interconnect Medium-speed chip-, module-, and system-level interconnect Major Component Support Xilinx Many Fulcrum Microsystems,B roadcom, Vitesse, Marvell Mellanox PLX Technology, Intel, StarGen, Tundra, IDT, AMCC, Freescale, TI, Marvell, Broadcom Tundra, Freescale, TI StarGen VME Board-level Vendors Advantages Disadvantages VMETRO, Pentek, 4DSP, Tekmicro, Micro Memory, Nallatech, GE Fanuc Lightweight protocol, high speed Not a switched fabric, no silicon outside of FPGAs Many Well-known, safe technology High overhead for header processing, no QoS standard Built upon ubiquitous GigE High overhead for header processing, No auto-negotiation down to slower speeds GE Fanuc High data rates S/W complexity, limited ecosystem support Cornet Technology, VMETRO, Tekmicro, RECAB, Mercury Computer, GE Fanuc, Curtiss- Wright Legacy software compatibility, fairly low header processing O/H Difficult to implement large arrays Mercury Computer, Micro Memory, VMETRO, Pentek Simplicity and low O/H, intraand interchassis suitability, more flexible topology No path from legacy systems / code, smaller support group due to lack of interest from PC market, minimal chip level support Curtiss-Wright, GE Fanuc, Micro Memory Backwards compatible to PCI (address method) Low speed 10