The Uniboard  FPGA Processing for Astronomy Harro Verkouter/Joint Institute for VLBI in Europe

Joint Institute for VLBI in Europe MarkIV Correlator inaugurated 1998 In realtime: 16 stations 256MHz/station (1Gbit/s/station) 16 spectral points/subband resolution 0.25s shortest integration time ASIC based 1024 correlator chips running at 32MHz Problems 1993 state-of-the-art hardware EVN growing to > 16 stations new receivers yield > 1Gbps/station

EVN 2015 sciencegoals Correlator 100-fold more powerfull Multiple data streams of 10 - 100 Gbps at least 2GHz BW/station Definitely more than 16 stations (32?) 10ms shortest integration time Correlator 100-fold more powerfull software correlators exist, best performance estimate: 128 dual quad-core nodes for realtime 16 stations @ 1Gbps does give 8x higher spectral resolution sweet spot for performance/watt/developmentcost = FPGA conclusion of “Next generation correlators” workshop, Groningen (NL) 2006

The Uniboard Built according to Pogrebenko* meltdown criterion: “Put as many state-of-the-art FPGAs and high speed links on one board as possible.” Attempt to yield: as much processing power per board as possible as much I/O connectivity as possible * Sergei Pogrebenko - digital engineer at JIVE

The Uniboard 4x 10 Gbps 4x 8 bit LVDS Backplane side Front panel side 4x10Gbps ethernet, 4GB DDR3, InterFPGA = 20Gbps

Features 8 Altera Stratix IV FPGA, 40nm technology 800+ k Logical Elements 1200 18x18 multipliers goal is to run the board at 400MHz => 3 TMAC/s Xilinx also has comparable 40nm FPGA not at affordable cost not in foreseeable future old correlator does ~ 100TMAC/s but is XF architecture (requires 10x as much MAC) need 4 UniBoards to equal EVN MkIV correlator Stratix type: EP4SGX230KF40 TMAC = Tera Multiply-Accumulate EVN MkIV = 32MHz * 1k chips * 0.5k lags * 6MAC/lag = 100TMAC UniBoard = 8 chips * 1k MAC * 400MHz = 3.2 TMAC

Powerconsumption estimates Power each Number Total FPGA 20 W 8 160 W Interfaces (10GbE) 2 W 16 32 W Memory (DDR3) 2.5 W 40 W Power supply loss 20% 1 46 W Total power 280 W Stratix type: EP4SGX230KF40 TMAC = Tera Multiply-Accumulate MarkIV correlator ~10kW

EVN Correlator Telescope Correlator Telescope Correlator Based on independence of subbands Telescope Correlator UniBoard Sample filter receiver splitter Telescope Correlator UniBoard buffer/ FFT X-Corr UniBoard buffer/ FFT X-Corr Stratix type: EP4SGX230KF40 TMAC = Tera Multiply-Accumulate UniBoard buffer/ FFT X-Corr

Other projects using UniBoard APERTIF - for focalplane-array equipped WSRT beamformer correlate everything with everything Digital Receiver using board in reverse, sample signal at the LVDS connectors European Pulsar Timing Array detect gravitational waves by detecting correlations between residuals on an ‘array’ of pulsars Pulsar Binning provide coherent de-dispersion over ~10 times broader bandwidth RFI Mitigation computational power + bandwidth allows to do this on-the-fly not for dynamic RFI signals (e.g. WiFi) Stratix type: EP4SGX230KF40 TMAC = Tera Multiply-Accumulate

RadioNet/FP7 Joint Research Activity EC integrating activity that brings together all the major radio observatories in Europe EC funding round #7 (framework programme) awarded 2M€ over next 3 years started January 2009 26 partners