Presentation on theme: "Towards a Scalable and Reliable Wireless Network-on-Chip"— Presentation transcript:
1Towards a Scalable and Reliable Wireless Network-on-Chip 4/7/2017Towards a Scalable and Reliable Wireless Network-on-ChipAmlan Ganguly, Ph.D School of EECS, Washington State UniversityTemplate C Plain-crimson-bright
24/7/2017OutlineIntroductionMulti-core & Network-on-Chip (NoC) paradigmPerformance limitations of conventional planar NoCsAlternative interconnect technologyWireless NoC (WiNoC)On-chip antennasArchitecture & communication protocolsPerformance evaluationReliabilityError Control CodingWireline linksWireless linksFuture DirectionsTemplate C Plain-crimson-bright2
3The era of single processor systems is over Why Multi-Core Chips?The need for explosive computational powerScientific applicationsWeather prediction, AstrophysicsBioinformatics, forensicsLanguage processingConsumer electronicsGraphics, AnimationSoon be in the Exascale age!The era of single processor systems is over
4Moore’s Law: so far so good! The number of transistors on a chip doubles every 18 monthsHas provided the computational power demanded so farNow poses major challengesSoaring power dissipation due to scaling frequency upOriginal Moore's Law graph, 1965
5Power Density (Watts/cu. m) Power DissipationScaling up speed/frequency is impossible0.11101001,00010,000’71’74’78’85’92’00’04’08Power Density (Watts/cu. m)40048008808080858086286386486Pentium®processorsSun’s SurfaceRocket NozzleNuclear ReactorHot PlateSource: Intel
6The era of Multi-Core systems Nokia SparrowTo keep up with demands on computational powerScaling of clock frequency is not possibleSolution: Increase number of cores - parallelismIntel, AMD dual-core and quad-core CPUsCustom Systems-on-Chip (SoCs)Number of cores need to increase manifold in the next 5-10 yearsIntel 80 core processorNew challenge: interconnection of the cores!
7The new interconnection paradigm: Network-on-Chip (NoC) Driven byMassive levels of integrationNew designs counting 100s of embedded coresNeed for platform-based interconnection infrastructuretime-to-market
8NoC Features and Advantages Packet switched on-chip networkRoute packets, not wires –Bill Dally, 2000.Dedicated infrastructure for data transportDecoupling of functionality from communicationAMBA bus: ARMNoC infrastructureMultiple publications in IEEE ISSCC, 2010 from Intel, IBM, AMD, Renesas Tech. and Sun Microsystems show that multi-core NoC is a reality
94/7/2017OutlineIntroductionMulti-core & Network-on-Chip (NoC) paradigmPerformance limitations of conventional planar NoCsAlternative interconnect technologyWireless NoC (WiNoC)On-chip antennasArchitecture & communication protocolsPerformance evaluationReliabilityError Control CodingWireline linksWireless linksFuture Directions9Template C Plain-crimson-bright9
10Limitations of a Traditional NoC Multi-hop wireline communicationHigh Latency and energy dissipationsourcedestinationcoreNoC interfaceNoC switch80% of chip power will be from on-chip interconnects in the next 5 years – ITRS, 2007
11Novel Interconnect Paradigms for Multicore designs Optical InterconnectsThree DimensionalIntegrationWireless/RFInterconnectsHigh Bandwidth andLow Energy Dissipation11
123D NoC Stacking multiple active layers Manufacturability Mismatch between various layersYield is an issueTemperature concernsDespite power advantages, reduced footprint increases power densityPavlidis et al., “3-D topologies for Networks-on-Chip”, IEEE Transactions on Very Large Scale Integration (TVLSI), 2007.
13Photonic NoC High bandwidth photonic links for high payload transfers Challenges: On-going researchOn-chip integration of photonic componentsA. Shacham et al., “Photonic Network-on-Chip for Future Generations of Chip Multi-Processors”, IEEE Transactions on Computers, 2008.
14NoC with RF Interconnects Use of transmission lines out of package or IC structures like parallel metal wiresChallenges:Routing of long transmission lines without eliminating any existing linksCauses hotspots at drop-pointsM. F. Chang et al. “CMP Network-on-Chip Overlaid With Multi-Band RF-Interconnect”, Proc. of IEEE International Symposium on High-Performance Computer Architecture (HPCA), 2008.
15State-of-the-art in emerging NoCs 3D NoCPhotonic NoCNoC with RF-IDesign RequirementsMultiple layers with active devicesSilicon photonic componentsOn-chip waveguidePerformance GainsBandwidthHigher connectivity & less hop countHigh speed optical devices and linksHigh bandwidth RF waveguideLower PowerShorter average path lengthNegligible power dissipation in optical data transportLow power dissipation in RF-IReliabilityVertical Via FailureCrosstalk in photonic waveguidesSignal interference in the waveguideChallengesHeat dissipation due to higher power densityIntegration of on-chip photonic componentsPrecision high frequency oscillators and filters
164/7/2017OutlineIntroductionMulti-core & Network-on-Chip (NoC) paradigmPerformance limitations of conventional planar NoCsAlternative interconnect technologyWireless NoC (WiNoC)On-chip antennasArchitecture & communication protocolsPerformance evaluationReliabilityError Control CodingWireline linksWireless linksFuture Directions16Template C Plain-crimson-bright16
17The Wireless Network-on-Chip (WiNoC) Use of on-chip wireless linksHigh bandwidth: 500 Gbps - ~ 1 TbpsWires: ~ 3 GbpsLatency: True speed-of-lightWires: ~ 400 psLong distance: ~ 15 mm - 25 mmWires: ~ mmNo physical interconnect layout is necessaryReduce latency and energy dissipation in communication
18Early example of on-chip wireless interconnects First utilized for distribution of clock signalTechnology: 0.18 um CMOSOperating frequency: 15 GHzSingle ToneModulation and Channelization was not a concernFloyd et al., IEEE Journal of Solid-State Circuits,2002.
19Adopted Technology: Carbon Nanotube (CNT) antennas High B/W, frequency light (IR, visible, UV)Small wavelength: small antennasless areaCNTs as Optical AntennasDirectional radiation characteristicsQuantitative agreement with conventional radio antenna theory and simulationsLaser excitationKempa, et al., "Carbon Nanotubes as Optical Antennae," Advanced Materials, 2007.Slepyan, et al., "Theory of optical scattering by achiral carbon nanotubes and their potential as optical nanoantennas," Physical Review B, 2006.
20How to efficiently distribute the wireless resources? Design ConstraintsEverything fine?Limited wireless channelsOff-chip laser sourcesOn-chip wireless nodes have associated overheadTransceiverModulator/demodulatorantennasHow to efficiently distribute the wireless resources?
21Hybrid nature of the WiNoC Augment wireline with wirelessNot completely wirelessDivide the whole NoC into multiple subnetsCommunication within the subnets is still through wiresUtilize wireless links for inter-subnet data exchangeEach subnet will have a hubEquipped with Wireless Base Station (WB)Subnet architectures may vary and even be heterogeneous on the same chip
22Network Design Principles TopologyEstablish connectivity among the subnets through hubsReduce multi-hop communication using the wireless channelsNear constant bandwidth over all range of communicationCan be used as long-distance shortcutsAdopt SMALL-WORLD network topologyCommunication mechanismHow to send bits through the CNT antennasMinimize the WB overheadSimple yet efficient physical layer
23Connecting the Hubs Small-World graphs: The Watts-Strogatz Model Often found in natureScales well: low average distanceregular latticeL: HiC: Hirandom graphL: LoC: LoSmall-worldL: LoC: HiFew high speed shortcuts: WirelessLocal, shorter links: Wireline
24Proposed Hybrid, Hierarchical WiNoC Architecture Mesh-based wireline subnetsEach subnet has a hubInterconnected with neighboring hubs in a ring topologySome hubs have WBsProviding wireless shortcutsCreating small-world topology in the upper level
25How to establish wireless links? Simulated Annealing Shortcuts, but where?Optimization metricDistance, frequency of communicationConvergence is faster than exhaustive searchScalable techniqueStable convergence for several cooling profiles
26Network Design Principles TopologyEstablish connectivity among the subnets through hubsReduce multi-hop communication using the wireless channelsNear constant bandwidth over all range of communicationCan be used as long-distance shortcutsAdopt SMALL-WORLD network topologyCommunication mechanismHow to send bits through the CNT antennasMinimize the WB overheadSimple yet efficient physical layer26
27Communication mechanisms with CNT antennas Multiband laser sources to excite the antennasFrequency Division Multiplexing (FDM)Different frequency channels can be assigned to pairs of communicating subnetsAntenna elements tuned to different frequenciesNo complex MAC requiredElectro-Optic ConversionsMach-Zehnder Modulators (MZM)Perform OOK on light carrierSupported B/W of 10Gbps/channelAn ultra compact 10 Gbps silicon modulatorGreen et. al., “Ultra-compact, low RF power, 10Gb/s silicon Mach-Zehnder modulator,” Optics Express, 2007
28Adopted channelization scheme 32-bit flit width24 distinct frequency channelsTotal wireless B/W of 240 Gbpsm wireless links1-24 links24/m distinct frequency channels per linkCombination of FDM and TDM.
29Performance Evaluation Comparison with Flat wireline meshScaling methods with sizeComparisons with other emerging NoCsOverheads
30Compared with flat wireline mesh System size: 256 coresThroughputPacket EnergySystem SizeFlat Mesh (nJ)WiNoC (nJ)ratio128131922.5758256293624.02122512499237.48133Orders of magnitude less !Gets better with sizeGanguly et al., “Scalable Hybrid Wireless Network-on-Chip Architectures for Multi-Core Systems”, IEEE Transactions on Computers (TC), 2010.
31Establishment of scaling trend Packet Energy dissipationVarying subnet size and numberVarying number of wireless linksScales better with increase in number of subnets
32Comparative Performance Evaluation Case study:128 coresAchievable network bandwidthPacket Energy dissipationWiNoC performs best
33About 10-20% area overhead depending on the system size OverheadsArea OverheadWiring overheadsAdditional linksCore-hubInter-hubAbout 10-20% area overhead depending on the system size
34Summary of WiNoC Performance Up to 2 orders of magnitude less energy dissipationMuch higher bandwidth compared to wireline NoCs of same sizeBetter performance than all other emerging NoC paradigmsReasonable real estate overheads
354/7/2017OutlineIntroductionMulti-core & Network-on-Chip (NoC) paradigmPerformance limitations of conventional planar NoCsAlternative interconnect technologyWireless NoC (WiNoC)On-chip antennasArchitecture & communication protocolsPerformance evaluationReliabilityError Control CodingWireline linksWireless linksFuture Directions35Template C Plain-crimson-bright35
36Reliability and Signal Integrity According to ITRS signal integrity will become a major issue in future technologiesShrinking geometries: less charge/informationIncreased probability of transient events like:CrosstalkGround BounceAlpha particle hitsWiNoCsUse of inherently defect prone CNT technologyError Control Coding is a solution36
39Energy Dissipation Characteristics ECCs in subnet links64 core wireline NoC33%47%Ganguly et al., “Crosstalk-Aware Channel Coding Schemes for Energy Efficient and Reliable NoC Interconnects”, IEEE Transactions on VLSI (TVLSI) 2009.39
40ECC: Wireless linksEach CNT antenna element responsible for multiple bit transmissionBurst ErrorsMulti-bit errorMulti-path interferencePackaging surfaces40
41SNR & BER Single transmitter position Reception across die area Non-coherent OOK modem0.001
42Structure of the product code encoder Using simple ECCs on both spatial and time axesHamming codesHamming-Product Code (H-PC)Structure of the product code encoder
43Results Increase reliability Keep energy dissipation low Low latency
444/7/2017OutlineIntroductionMulti-core & Network-on-Chip (NoC) paradigmPerformance limitations of conventional planar NoCsAlternative interconnect technologyWireless NoC (WiNoC)On-chip antennasArchitecture & communication protocolsPerformance evaluationReliabilityError Control CodingWireline linksWireless linksFuture Directions44Template C Plain-crimson-bright44
45Future Directions Wireless NoCs with millimeter-wave Interconnects Extension of the ECC schemesUnified design framework with alternative interconnect technologiesComplex Networks
46Alternative Antennas CNTs still have manufacturing issues Metal Zig-Zag antennasBandwidth: ~ tens of GHz
47Another alternative antenna Electrolumiscence in CNTsNo separate modulator/demodulators requiredMuch less overheadRange of communication needs to be investigatedCan be used for short range wireless interconnectsNojeh et. al., "Reliability of wireless on-chip interconnects based on carbon nanotube antennas," International Mixed-Signals, Sensors, and Systems Test Workshop (IMS3TW), 2008.
48Extension of ECC schemes Use of multiple error correction codesSpaceTimeBothCorrect multiple bursts in either directionBCH codesRS codesStudy performancePerformance-overhead trade-offs
49Unified Framework All alternative interconnect technologies Network topologies with all the possible interconnectsDetermine each one’s spot in the design spaceLook across varying granularity for optimizationNodes: subnets to even devicesDevelop CAD methodologies for novel interconnectsCan an optimal solution for N cores readily be scaled up to 10N or 1000N cores?If not, what is the difference and what are the design rules as the system scales up?Super low-power interconnectsSustainability of computing: ScalabilityGreen computing paradigms
50Fault Tolerance: Complex Networks Small-World/Exponential graphsNodes with similar degreesResilient to targeted attacksScale-free graphsFew high-degree nodesResilient to random failuresR. Albert, H. Jeong and A. Barabási, “Error and Attack Tolerance of Complex Networks”, Nature, Vol. 406, July 2000, pp
51Conclusions NoC is a reality Alternative interconnect technology Limitations: performance & energyAlternative interconnect technologyHigh bandwidth, low powerLong distance shortcutsAdopt nature-inspired topologiesOptimize networkIncrease reliabilityECCComplex Network theory
52Journal PublicationsAmlan Ganguly, Kevin Chang, Sujay Deb, Partha Pande, Benjamin Belzer, Christof Teuscher, “Scalable Hybrid Wireless Network-on-Chip Architectures for Multi-Core Systems”, IEEE Transactions on Computers (TC), June, 2010, accepted for publication.Amlan Ganguly, Partha Pande, Benjamin Belzer, “Crosstalk-Aware Channel Coding Schemes for Energy Efficient and Reliable NoC Interconnects”, IEEE Transactions on VLSI (TVLSI) Vol. 17, No.11, November 2009, ppAmlan Ganguly, Partha Pande, Benjamin Belzer, Cristian Grecu, "Design of Low power & Reliable Networks on Chip through joint Crosstalk Avoidance and Multiple Error Correction Coding", Journal of Electronic Testing: Theory and Applications (JETTA), Special Issue on Defect and Fault Tolerance, June 2008, ppPartha Pande, Amlan Ganguly, Haibo Zhu, Cristian Grecu, “Energy Reduction through Crosstalk Avoidance Coding in Networks on Chip", Journal of System Architecture (JSA), Vol. 54/ 3-4, March-April 2008, pp
53Conference Publications/Book Chapters Partha Pratim Pande, Cristian Grecu, Amlan Ganguly, Andre Ivanov, and Resve Saleh, “Test and Fault Tolerance of NoC Infrastructures”, In Networks-on-Chips: Theory and Practice, Fayez Gebali, Haytham Elmiligi, and M.Watheq El-Kharashi (eds.), Taylor & Francis Group LLC - CRC Press.Sujay Deb, Kevin Chang, Amlan Ganguly and Partha Pande, “Comparative Performance Evaluation of Wireless and Optical NoC Architectures”, Proceedings of IEEE International SOC Conference (SOCC), 27th-29th September 2010.Sujay Deb, Amlan Ganguly, Kevin Chang, Benjamin Belzer, Deuk Heo, “Enhancing Performance of Network-on-Chip Architectures with Millimeter-Wave Wireless Interconnects”, Proceedings of IEEE International Conference on Application-specific Systems, Architectures and Processors (ASAP), 2010.Partha Pande, Amlan Ganguly, Kevin Chang, Christof Teuscher, “Hybrid Wireless Network-on-Chip: A New Paradigm in Multi-Core Design”, invited paper, Second International Workshop on Network-on-Chip Architectures (NoCArc), December 12, 2009.Amlan Ganguly, Kevin Chang, Partha Pratim Pande, Benjamin Belzer and Alireza Nojeh, "Performance Evaluation of Wireless Networks on Chip Architectures", Proceedings of the IEEE International Symposium on Quality Electronic Design (ISQED), 16th-18th March 2009.Partha Pande, Amlan Ganguly, Benjamin Belzer, Alireza Nojeh, Andre Ivanov, “Novel Interconnect Infrastructures for Massive Multicore Chips”, Proceedings of IEEE Symposium on Circuits and Systems (ISCAS) , May, 2008, pp
54Conference Publications contd. A. Nojeh, P. Pande, A. Ganguly, S. Sheikhaei, B. Belzer and A. Ivanov, "Reliability of wireless on-chip interconnects based on carbon nanotube antennas," Proceedings of IEEE International Mixed-Signals, Sensors, and Systems Test Workshop (IMS3TW) June 2008, pp. 1-6.Amlan Ganguly, Partha Pande, Benjamin Belzer, Cristian Grecu, “Addressing Signal Integrity in Networks on Chip Interconnects through Crosstalk-Aware Double Error Correction Coding”, Proceedings of IEEE Computer Society Annual Symposium on VLSI (ISVLSI) 2007, May, 2007, ppPartha Pande, Amlan Ganguly, Brett Feero, Cristian Grecu, “Applicability of Energy Efficient Coding Methodology to Address Signal Integrity in 3D NoC Fabrics”, Proceedings of IEEE International ON-line Test Symposium (IOLTS), July, 2007, ppPartha Pande, Amlan Ganguly, Brett Feero, Benjamin Belzer, Cristian Grecu, "Design of Low Lower & Reliable Networks on Chip through Joint Crosstalk Avoidance and Forward Error Correction Coding", Proceedings of IEEE Defect and Fault Tolerance in VLSI Systems (DFT), 2006, pp. 466 – 476.Partha Pande, Haibo Zhu, Amlan Ganguly, Cristian Grecu, “Energy Reduction through Crosstalk Avoidance Coding in NoC Paradigm", Proceedings of IEEE EUROMICRO Conference on Digital System Design: Architectures, Methods and Tools (DSD) 2006, pp. 689 – 695.Partha Pratim Pande, Haibo Zhu, Amlan Ganguly, Cristian Grecu, "Crosstalk-aware Energy Reduction in NoC Communication Fabrics", Proceedings of IEEE International SOC Conference (SOCC), 2006, pp. 225 – 228.
55Acknowledgements Advisor Collaborators Colleagues in my Lab Family Dr. Partha Pande, WSUthrough NSF CAREER GrantCollaboratorsDr. Benjamin Belzer, WSUDr. Alireza Nojeh, UBCDr. Christof Teuscher, PSUDr. Deuk Heo, WSUIntel, CRL, ORColleagues in my LabMr. Kevin Chang, WSUMr. Sujay Deb, WSUFamilyParentsRini