OpticalLinkBackendRx.cc revision 10447
110447Snilay@cs.wisc.edu#include "model/optical/OpticalLinkBackendRx.h" 210447Snilay@cs.wisc.edu 310447Snilay@cs.wisc.edu#include "util/Constants.h" 410447Snilay@cs.wisc.edu#include "model/PortInfo.h" 510447Snilay@cs.wisc.edu#include "model/TransitionInfo.h" 610447Snilay@cs.wisc.edu#include "model/EventInfo.h" 710447Snilay@cs.wisc.edu#include "model/electrical/DemuxTreeDeserializer.h" 810447Snilay@cs.wisc.edu#include "model/electrical/BarrelShifter.h" 910447Snilay@cs.wisc.edu#include "model/electrical/Multiplexer.h" 1010447Snilay@cs.wisc.edu#include <cmath> 1110447Snilay@cs.wisc.edu 1210447Snilay@cs.wisc.edunamespace DSENT 1310447Snilay@cs.wisc.edu{ 1410447Snilay@cs.wisc.edu // TODO: Kind of don't like the way thermal tuning is written here. Maybe will switch 1510447Snilay@cs.wisc.edu // to curve fitting the CICC paper, which uses results from a monte-carlo sim. Also, there is 1610447Snilay@cs.wisc.edu // redundant code between this one and the tx one... 1710447Snilay@cs.wisc.edu 1810447Snilay@cs.wisc.edu OpticalLinkBackendRx::OpticalLinkBackendRx(const String& instance_name_, const TechModel* tech_model_) 1910447Snilay@cs.wisc.edu : ElectricalModel(instance_name_, tech_model_) 2010447Snilay@cs.wisc.edu { 2110447Snilay@cs.wisc.edu initParameters(); 2210447Snilay@cs.wisc.edu initProperties(); 2310447Snilay@cs.wisc.edu } 2410447Snilay@cs.wisc.edu 2510447Snilay@cs.wisc.edu OpticalLinkBackendRx::~OpticalLinkBackendRx() 2610447Snilay@cs.wisc.edu {} 2710447Snilay@cs.wisc.edu 2810447Snilay@cs.wisc.edu void OpticalLinkBackendRx::initParameters() 2910447Snilay@cs.wisc.edu { 3010447Snilay@cs.wisc.edu addParameterName("OutBits"); 3110447Snilay@cs.wisc.edu addParameterName("CoreDataRate"); 3210447Snilay@cs.wisc.edu addParameterName("LinkDataRate"); 3310447Snilay@cs.wisc.edu addParameterName("RingTuningMethod"); 3410447Snilay@cs.wisc.edu addParameterName("BitDuplicate"); 3510447Snilay@cs.wisc.edu return; 3610447Snilay@cs.wisc.edu } 3710447Snilay@cs.wisc.edu 3810447Snilay@cs.wisc.edu void OpticalLinkBackendRx::initProperties() 3910447Snilay@cs.wisc.edu { 4010447Snilay@cs.wisc.edu return; 4110447Snilay@cs.wisc.edu } 4210447Snilay@cs.wisc.edu 4310447Snilay@cs.wisc.edu void OpticalLinkBackendRx::constructModel() 4410447Snilay@cs.wisc.edu { 4510447Snilay@cs.wisc.edu unsigned int out_bits = getParameter("OutBits"); 4610447Snilay@cs.wisc.edu double core_data_rate = getParameter("CoreDataRate"); 4710447Snilay@cs.wisc.edu double link_data_rate = getParameter("LinkDataRate"); 4810447Snilay@cs.wisc.edu const String& tuning_method = getParameter("RingTuningMethod"); 4910447Snilay@cs.wisc.edu bool bit_duplicate = getParameter("BitDuplicate"); 5010447Snilay@cs.wisc.edu 5110447Snilay@cs.wisc.edu // Calculate deserialization ratio 5210447Snilay@cs.wisc.edu unsigned int deserialization_ratio = (unsigned int) floor(link_data_rate / core_data_rate); 5310447Snilay@cs.wisc.edu ASSERT(deserialization_ratio == link_data_rate / core_data_rate, 5410447Snilay@cs.wisc.edu "[Error] " + getInstanceName() + " -> Cannot have non-integer deserialization ratios!"); 5510447Snilay@cs.wisc.edu ASSERT((deserialization_ratio & (deserialization_ratio - 1)) == 0, 5610447Snilay@cs.wisc.edu "[Error] " + getInstanceName() + " -> Deserialization ratio must be a power of 2"); 5710447Snilay@cs.wisc.edu 5810447Snilay@cs.wisc.edu // Calculate output width 5910447Snilay@cs.wisc.edu unsigned int in_bits = out_bits / deserialization_ratio; 6010447Snilay@cs.wisc.edu ASSERT(out_bits >= deserialization_ratio, "[Error] " + getInstanceName() + 6110447Snilay@cs.wisc.edu " -> Output width must be >= deserialization ratio!"); 6210447Snilay@cs.wisc.edu ASSERT(floor((double) out_bits / deserialization_ratio) == in_bits, 6310447Snilay@cs.wisc.edu "[Error] " + getInstanceName() + " -> Output width must be a multiple of the serialization ratio!"); 6410447Snilay@cs.wisc.edu 6510447Snilay@cs.wisc.edu getGenProperties()->set("DeserializationRatio", deserialization_ratio); 6610447Snilay@cs.wisc.edu getGenProperties()->set("InBits", in_bits); 6710447Snilay@cs.wisc.edu 6810447Snilay@cs.wisc.edu // Create ports 6910447Snilay@cs.wisc.edu createInputPort("In", makeNetIndex(0, in_bits-1)); 7010447Snilay@cs.wisc.edu createInputPort("LinkCK"); 7110447Snilay@cs.wisc.edu createOutputPort("Out", makeNetIndex(0, out_bits-1)); 7210447Snilay@cs.wisc.edu 7310447Snilay@cs.wisc.edu //Create energy, power, and area results 7410447Snilay@cs.wisc.edu createElectricalResults(); 7510447Snilay@cs.wisc.edu // Create ring heating power cost 7610447Snilay@cs.wisc.edu addNddPowerResult(new AtomicResult("RingTuning")); 7710447Snilay@cs.wisc.edu // Create process bits event 7810447Snilay@cs.wisc.edu createElectricalEventResult("ProcessBits"); 7910447Snilay@cs.wisc.edu getEventInfo("ProcessBits")->setTransitionInfo("LinkCK", TransitionInfo(0.0, (double) deserialization_ratio / 2.0, 0.0)); 8010447Snilay@cs.wisc.edu // Set conditions during idle state 8110447Snilay@cs.wisc.edu getEventInfo("Idle")->setStaticTransitionInfos(); 8210447Snilay@cs.wisc.edu getEventInfo("Idle")->setTransitionInfo("LinkCK", TransitionInfo(0.0, (double) deserialization_ratio / 2.0, 0.0)); 8310447Snilay@cs.wisc.edu 8410447Snilay@cs.wisc.edu // Create deserializer 8510447Snilay@cs.wisc.edu const String& deserializer_name = "Deserializer"; 8610447Snilay@cs.wisc.edu DemuxTreeDeserializer* deserializer = new DemuxTreeDeserializer(deserializer_name, getTechModel()); 8710447Snilay@cs.wisc.edu deserializer->setParameter("OutBits", out_bits); 8810447Snilay@cs.wisc.edu deserializer->setParameter("InDataRate", link_data_rate); 8910447Snilay@cs.wisc.edu deserializer->setParameter("OutDataRate", core_data_rate); 9010447Snilay@cs.wisc.edu deserializer->setParameter("BitDuplicate", bit_duplicate); 9110447Snilay@cs.wisc.edu deserializer->construct(); 9210447Snilay@cs.wisc.edu 9310447Snilay@cs.wisc.edu addSubInstances(deserializer, 1.0); 9410447Snilay@cs.wisc.edu addElectricalSubResults(deserializer, 1.0); 9510447Snilay@cs.wisc.edu getEventResult("ProcessBits")->addSubResult(deserializer->getEventResult("Deserialize"), deserializer_name, 1.0); 9610447Snilay@cs.wisc.edu 9710447Snilay@cs.wisc.edu if ((tuning_method == "ThermalWithBitReshuffle") || (tuning_method == "ElectricalAssistWithBitReshuffle")) 9810447Snilay@cs.wisc.edu { 9910447Snilay@cs.wisc.edu // If a bit reshuffling backend is present, create the reshuffling backend 10010447Snilay@cs.wisc.edu unsigned int reorder_degree = getBitReorderDegree(); 10110447Snilay@cs.wisc.edu 10210447Snilay@cs.wisc.edu // Create intermediate nets 10310447Snilay@cs.wisc.edu createNet("ReorderIn", makeNetIndex(0, in_bits+reorder_degree-1)); 10410447Snilay@cs.wisc.edu assign("ReorderIn", makeNetIndex(0, in_bits-1), "In"); 10510447Snilay@cs.wisc.edu assign("ReorderIn", makeNetIndex(in_bits, in_bits+reorder_degree-1), "ReorderIn", makeNetIndex(0, reorder_degree-1)); 10610447Snilay@cs.wisc.edu createNet("DeserializerIn", makeNetIndex(0, in_bits-1)); 10710447Snilay@cs.wisc.edu createNet("BarrelShiftIn", makeNetIndex(0, out_bits-1)); 10810447Snilay@cs.wisc.edu 10910447Snilay@cs.wisc.edu // Create bit reorder muxes 11010447Snilay@cs.wisc.edu const String& reorder_mux_name = "ReorderMux"; 11110447Snilay@cs.wisc.edu Multiplexer* reorder_mux = new Multiplexer(reorder_mux_name, getTechModel()); 11210447Snilay@cs.wisc.edu reorder_mux->setParameter("NumberBits", in_bits); 11310447Snilay@cs.wisc.edu reorder_mux->setParameter("NumberInputs", reorder_degree); 11410447Snilay@cs.wisc.edu reorder_mux->setParameter("BitDuplicate", bit_duplicate); 11510447Snilay@cs.wisc.edu reorder_mux->construct(); 11610447Snilay@cs.wisc.edu 11710447Snilay@cs.wisc.edu // Create barrelshifter 11810447Snilay@cs.wisc.edu unsigned int shift_index_min = (unsigned int)ceil(log2(deserialization_ratio)); 11910447Snilay@cs.wisc.edu unsigned int shift_index_max = std::max(shift_index_min, (unsigned int) ceil(log2(out_bits)) - 1); 12010447Snilay@cs.wisc.edu 12110447Snilay@cs.wisc.edu // Remember some things 12210447Snilay@cs.wisc.edu getGenProperties()->set("ReorderDegree", reorder_degree); 12310447Snilay@cs.wisc.edu getGenProperties()->set("ShiftIndexMin", shift_index_min); 12410447Snilay@cs.wisc.edu getGenProperties()->set("ShiftIndexMax", shift_index_max); 12510447Snilay@cs.wisc.edu 12610447Snilay@cs.wisc.edu const String& barrel_shift_name = "BarrelShifter"; 12710447Snilay@cs.wisc.edu BarrelShifter* barrel_shift = new BarrelShifter(barrel_shift_name, getTechModel()); 12810447Snilay@cs.wisc.edu barrel_shift->setParameter("NumberBits", out_bits); 12910447Snilay@cs.wisc.edu barrel_shift->setParameter("ShiftIndexMax", shift_index_max); 13010447Snilay@cs.wisc.edu barrel_shift->setParameter("ShiftIndexMin", shift_index_min); 13110447Snilay@cs.wisc.edu barrel_shift->setParameter("BitDuplicate", bit_duplicate); 13210447Snilay@cs.wisc.edu barrel_shift->construct(); 13310447Snilay@cs.wisc.edu 13410447Snilay@cs.wisc.edu // Connect serializer 13510447Snilay@cs.wisc.edu portConnect(deserializer, "In", "DeserializerIn"); 13610447Snilay@cs.wisc.edu portConnect(deserializer, "Out", "BarrelShiftIn"); 13710447Snilay@cs.wisc.edu portConnect(deserializer, "InCK", "LinkCK"); 13810447Snilay@cs.wisc.edu 13910447Snilay@cs.wisc.edu // Connect barrelshifter 14010447Snilay@cs.wisc.edu // TODO: Connect barrelshift shifts! 14110447Snilay@cs.wisc.edu portConnect(barrel_shift, "In", "BarrelShiftIn"); 14210447Snilay@cs.wisc.edu portConnect(barrel_shift, "Out", "Out"); 14310447Snilay@cs.wisc.edu 14410447Snilay@cs.wisc.edu // Connect bit reorder muxes 14510447Snilay@cs.wisc.edu // TODO: Connect re-order multiplex select signals! 14610447Snilay@cs.wisc.edu for (unsigned int i = 0; i < reorder_degree; i++) 14710447Snilay@cs.wisc.edu portConnect(reorder_mux, "In" + (String) i, "ReorderIn", makeNetIndex(i, i+in_bits-1)); 14810447Snilay@cs.wisc.edu portConnect(reorder_mux, "Out", "DeserializerIn"); 14910447Snilay@cs.wisc.edu 15010447Snilay@cs.wisc.edu addSubInstances(barrel_shift, 1.0); 15110447Snilay@cs.wisc.edu addSubInstances(reorder_mux, 1.0); 15210447Snilay@cs.wisc.edu addElectricalSubResults(barrel_shift, 1.0); 15310447Snilay@cs.wisc.edu addElectricalSubResults(reorder_mux, 1.0); 15410447Snilay@cs.wisc.edu getEventResult("ProcessBits")->addSubResult(barrel_shift->getEventResult("BarrelShift"), barrel_shift_name, 1.0); 15510447Snilay@cs.wisc.edu getEventResult("ProcessBits")->addSubResult(reorder_mux->getEventResult("Mux"), reorder_mux_name, 1.0); 15610447Snilay@cs.wisc.edu } 15710447Snilay@cs.wisc.edu else if ((tuning_method == "FullThermal") || (tuning_method == "AthermalWithTrim")) 15810447Snilay@cs.wisc.edu { 15910447Snilay@cs.wisc.edu // If no bit reshuffling backend is present, then just connect deserializer up 16010447Snilay@cs.wisc.edu portConnect(deserializer, "In", "In"); 16110447Snilay@cs.wisc.edu portConnect(deserializer, "Out", "Out"); 16210447Snilay@cs.wisc.edu portConnect(deserializer, "InCK", "LinkCK"); 16310447Snilay@cs.wisc.edu } 16410447Snilay@cs.wisc.edu else 16510447Snilay@cs.wisc.edu { 16610447Snilay@cs.wisc.edu ASSERT(false, "[Error] " + getInstanceName() + " -> Unknown ring tuning method '" + tuning_method + "'!"); 16710447Snilay@cs.wisc.edu } 16810447Snilay@cs.wisc.edu 16910447Snilay@cs.wisc.edu return; 17010447Snilay@cs.wisc.edu } 17110447Snilay@cs.wisc.edu 17210447Snilay@cs.wisc.edu void OpticalLinkBackendRx::updateModel() 17310447Snilay@cs.wisc.edu { 17410447Snilay@cs.wisc.edu // Update everyone 17510447Snilay@cs.wisc.edu Model::updateModel(); 17610447Snilay@cs.wisc.edu // Update ring tuning power 17710447Snilay@cs.wisc.edu getNddPowerResult("RingTuning")->setValue(getRingTuningPower()); 17810447Snilay@cs.wisc.edu return; 17910447Snilay@cs.wisc.edu } 18010447Snilay@cs.wisc.edu 18110447Snilay@cs.wisc.edu void OpticalLinkBackendRx::propagateTransitionInfo() 18210447Snilay@cs.wisc.edu { 18310447Snilay@cs.wisc.edu // Get parameters 18410447Snilay@cs.wisc.edu const String& tuning_method = getParameter("RingTuningMethod");; 18510447Snilay@cs.wisc.edu 18610447Snilay@cs.wisc.edu // Get properties 18710447Snilay@cs.wisc.edu 18810447Snilay@cs.wisc.edu // Update the deserializer 18910447Snilay@cs.wisc.edu if ((tuning_method == "ThermalWithBitReshuffle") || (tuning_method == "ElectricalAssistWithBitReshuffle")) 19010447Snilay@cs.wisc.edu { 19110447Snilay@cs.wisc.edu // Get generated properties 19210447Snilay@cs.wisc.edu unsigned int reorder_degree = getGenProperties()->get("ReorderDegree"); 19310447Snilay@cs.wisc.edu unsigned int shift_index_min = getGenProperties()->get("ShiftIndexMin"); 19410447Snilay@cs.wisc.edu unsigned int shift_index_max = getGenProperties()->get("ShiftIndexMax"); 19510447Snilay@cs.wisc.edu 19610447Snilay@cs.wisc.edu // Reorder mux shift select bits 19710447Snilay@cs.wisc.edu unsigned int reorder_sel_bits = (unsigned int)ceil(log2(reorder_degree)); 19810447Snilay@cs.wisc.edu 19910447Snilay@cs.wisc.edu // Create bit reorder muxes 20010447Snilay@cs.wisc.edu const String& reorder_mux_name = "ReorderMux"; 20110447Snilay@cs.wisc.edu ElectricalModel* reorder_mux = (ElectricalModel*) getSubInstance(reorder_mux_name); 20210447Snilay@cs.wisc.edu for (unsigned int i = 0; i < reorder_degree; ++i) 20310447Snilay@cs.wisc.edu propagatePortTransitionInfo(reorder_mux, "In" + (String) i, "In"); 20410447Snilay@cs.wisc.edu // Set select transitions to be 0, since these are statically configured 20510447Snilay@cs.wisc.edu for (unsigned int i = 0; i < reorder_sel_bits; ++i) 20610447Snilay@cs.wisc.edu reorder_mux->getInputPort("Sel" + (String) i)->setTransitionInfo(TransitionInfo(0.5, 0.0, 0.5)); 20710447Snilay@cs.wisc.edu reorder_mux->use(); 20810447Snilay@cs.wisc.edu 20910447Snilay@cs.wisc.edu // Update the deserializer 21010447Snilay@cs.wisc.edu ElectricalModel* deserializer = (ElectricalModel*) getSubInstance("Deserializer"); 21110447Snilay@cs.wisc.edu propagatePortTransitionInfo(deserializer, "In", reorder_mux, "Out"); 21210447Snilay@cs.wisc.edu propagatePortTransitionInfo(deserializer, "InCK", "LinkCK"); 21310447Snilay@cs.wisc.edu deserializer->use(); 21410447Snilay@cs.wisc.edu 21510447Snilay@cs.wisc.edu // Update barrel shifter 21610447Snilay@cs.wisc.edu const String& barrel_shift_name = "BarrelShifter"; 21710447Snilay@cs.wisc.edu ElectricalModel* barrel_shift = (ElectricalModel*) getSubInstance(barrel_shift_name); 21810447Snilay@cs.wisc.edu propagatePortTransitionInfo(barrel_shift, "In", deserializer, "Out"); 21910447Snilay@cs.wisc.edu // Set shift transitions to be very low (since it is affected by slow temperature time constants) 22010447Snilay@cs.wisc.edu for (unsigned int i = shift_index_min; i <= shift_index_max; ++i) 22110447Snilay@cs.wisc.edu barrel_shift->getInputPort("Shift" + (String) i)->setTransitionInfo(TransitionInfo(0.499, 0.001, 0.499)); 22210447Snilay@cs.wisc.edu barrel_shift->use(); 22310447Snilay@cs.wisc.edu 22410447Snilay@cs.wisc.edu // Set output transition info 22510447Snilay@cs.wisc.edu propagatePortTransitionInfo("Out", barrel_shift, "Out"); 22610447Snilay@cs.wisc.edu } 22710447Snilay@cs.wisc.edu else if ((tuning_method == "FullThermal") || (tuning_method == "AthermalWithTrim")) 22810447Snilay@cs.wisc.edu { 22910447Snilay@cs.wisc.edu // Update the deserializer 23010447Snilay@cs.wisc.edu ElectricalModel* deserializer = (ElectricalModel*) getSubInstance("Deserializer"); 23110447Snilay@cs.wisc.edu propagatePortTransitionInfo(deserializer, "In", "In"); 23210447Snilay@cs.wisc.edu propagatePortTransitionInfo(deserializer, "InCK", "LinkCK"); 23310447Snilay@cs.wisc.edu deserializer->use(); 23410447Snilay@cs.wisc.edu 23510447Snilay@cs.wisc.edu // Set output transition info 23610447Snilay@cs.wisc.edu propagatePortTransitionInfo("Out", deserializer, "Out"); 23710447Snilay@cs.wisc.edu } 23810447Snilay@cs.wisc.edu else 23910447Snilay@cs.wisc.edu { 24010447Snilay@cs.wisc.edu ASSERT(false, "[Error] " + getInstanceName() + " -> Unknown ring tuning method '" + tuning_method + "'!"); 24110447Snilay@cs.wisc.edu } 24210447Snilay@cs.wisc.edu 24310447Snilay@cs.wisc.edu return; 24410447Snilay@cs.wisc.edu } 24510447Snilay@cs.wisc.edu 24610447Snilay@cs.wisc.edu double OpticalLinkBackendRx::getRingTuningPower() 24710447Snilay@cs.wisc.edu { 24810447Snilay@cs.wisc.edu // Get properties 24910447Snilay@cs.wisc.edu const String& tuning_method = getParameter("RingTuningMethod");; 25010447Snilay@cs.wisc.edu unsigned int number_rings = getGenProperties()->get("InBits"); 25110447Snilay@cs.wisc.edu 25210447Snilay@cs.wisc.edu // Get tech model parameters 25310447Snilay@cs.wisc.edu double R = getTechModel()->get("Ring->Radius"); 25410447Snilay@cs.wisc.edu double n_g = getTechModel()->get("Ring->GroupIndex"); 25510447Snilay@cs.wisc.edu double heating_efficiency = getTechModel()->get("Ring->HeatingEfficiency"); 25610447Snilay@cs.wisc.edu // This can actually be derived if we know thermo-optic coefficient (delta n / delta T) 25710447Snilay@cs.wisc.edu double tuning_efficiency = getTechModel()->get("Ring->TuningEfficiency"); 25810447Snilay@cs.wisc.edu double sigma_r_local = getTechModel()->get("Ring->LocalVariationSigma"); 25910447Snilay@cs.wisc.edu double sigma_r_systematic = getTechModel()->get("Ring->SystematicVariationSigma"); 26010447Snilay@cs.wisc.edu double T_max = getTechModel()->get("Ring->TemperatureMax"); 26110447Snilay@cs.wisc.edu double T_min = getTechModel()->get("Ring->TemperatureMin"); 26210447Snilay@cs.wisc.edu double T = getTechModel()->get("Temperature"); 26310447Snilay@cs.wisc.edu 26410447Snilay@cs.wisc.edu // Get constants 26510447Snilay@cs.wisc.edu double c = Constants::c; 26610447Snilay@cs.wisc.edu double pi = Constants::pi; 26710447Snilay@cs.wisc.edu 26810447Snilay@cs.wisc.edu double tuning_power = 0.0; 26910447Snilay@cs.wisc.edu 27010447Snilay@cs.wisc.edu if (tuning_method == "ThermalWithBitReshuffle") 27110447Snilay@cs.wisc.edu { 27210447Snilay@cs.wisc.edu // When an electrical backend is present, rings only have to tune to the nearest channel 27310447Snilay@cs.wisc.edu // This can be approximated as each ring tuning to something exactly 1 channel away 27410447Snilay@cs.wisc.edu 27510447Snilay@cs.wisc.edu // Setup calculations 27610447Snilay@cs.wisc.edu double L = 2 * pi * R; // Optical length 27710447Snilay@cs.wisc.edu double FSR = c / (n_g * L); // Free spectral range 27810447Snilay@cs.wisc.edu double freq_sep = FSR / number_rings; // Channel separation 27910447Snilay@cs.wisc.edu 28010447Snilay@cs.wisc.edu // Calculate tuning power 28110447Snilay@cs.wisc.edu tuning_power = number_rings * freq_sep / (tuning_efficiency * heating_efficiency); 28210447Snilay@cs.wisc.edu } 28310447Snilay@cs.wisc.edu else if (tuning_method == "ElectricalAssistWithBitReshuffle") 28410447Snilay@cs.wisc.edu { 28510447Snilay@cs.wisc.edu // Electrical assistance allows for a fraction of the tuning range to be 28610447Snilay@cs.wisc.edu // covered electrically. This is most pronounced when the tuning range is small, 28710447Snilay@cs.wisc.edu // such is the case when bit reshuffling is applied 28810447Snilay@cs.wisc.edu 28910447Snilay@cs.wisc.edu // Get electrically tunable range 29010447Snilay@cs.wisc.edu double max_assist = getTechModel()->get("Ring->MaxElectricallyTunableFreq"); 29110447Snilay@cs.wisc.edu 29210447Snilay@cs.wisc.edu // Setup calculations 29310447Snilay@cs.wisc.edu double L = 2 * pi * R; // Optical length 29410447Snilay@cs.wisc.edu double FSR = c / (n_g * L); // Free spectral range 29510447Snilay@cs.wisc.edu double freq_sep = FSR / number_rings; // Channel separation 29610447Snilay@cs.wisc.edu double heating_range = std::max(0.0, freq_sep - max_assist); // The distance needed to bridge using heaters 29710447Snilay@cs.wisc.edu 29810447Snilay@cs.wisc.edu // Calculate tuning power, which is really only the power spent on heating since 29910447Snilay@cs.wisc.edu // distance tuned electrically is pretty much free 30010447Snilay@cs.wisc.edu tuning_power = number_rings * heating_range / (tuning_efficiency * heating_efficiency); 30110447Snilay@cs.wisc.edu } 30210447Snilay@cs.wisc.edu else if (tuning_method == "FullThermal") 30310447Snilay@cs.wisc.edu { 30410447Snilay@cs.wisc.edu // If there is no bit reshuffling backend, each ring must tune to an 30510447Snilay@cs.wisc.edu // absolute channel frequency. Since we can only heat rings (and not cool), 30610447Snilay@cs.wisc.edu // we can only red-shift (decrease frequency). Thus, a fabrication bias 30710447Snilay@cs.wisc.edu // must be applied such that under any process and temperature corner, the 30810447Snilay@cs.wisc.edu // ring resonance remains above channel resonance 30910447Snilay@cs.wisc.edu // I'll use 3 sigmas of sigma_r_local and sigma_r_systematic, and bias against 31010447Snilay@cs.wisc.edu // the full temperature range 31110447Snilay@cs.wisc.edu double fabrication_bias_freq = 3.0 * sqrt(pow(sigma_r_local, 2) + pow(sigma_r_systematic, 2)) + 31210447Snilay@cs.wisc.edu (T_max - T_min) * tuning_efficiency; 31310447Snilay@cs.wisc.edu 31410447Snilay@cs.wisc.edu // The local/systematic variations are 0 on average. Thus, the tuning distance can be calculated as 31510447Snilay@cs.wisc.edu double tuning_distance = fabrication_bias_freq - (T - T_min) * tuning_efficiency; 31610447Snilay@cs.wisc.edu 31710447Snilay@cs.wisc.edu // Tuning power needed is just the number of rings * tuning distance / (tuning and heating efficiencies) 31810447Snilay@cs.wisc.edu tuning_power = number_rings * tuning_distance / (tuning_efficiency * heating_efficiency); 31910447Snilay@cs.wisc.edu } 32010447Snilay@cs.wisc.edu else if (tuning_method == "AthermalWithTrim") 32110447Snilay@cs.wisc.edu { 32210447Snilay@cs.wisc.edu // Athermal! 32310447Snilay@cs.wisc.edu tuning_power = 0; 32410447Snilay@cs.wisc.edu } 32510447Snilay@cs.wisc.edu else 32610447Snilay@cs.wisc.edu { 32710447Snilay@cs.wisc.edu ASSERT(false, "[Error] " + getInstanceName() + " -> Unknown ring tuning method '" + tuning_method + "'!"); 32810447Snilay@cs.wisc.edu } 32910447Snilay@cs.wisc.edu 33010447Snilay@cs.wisc.edu return tuning_power; 33110447Snilay@cs.wisc.edu } 33210447Snilay@cs.wisc.edu 33310447Snilay@cs.wisc.edu unsigned int OpticalLinkBackendRx::getBitReorderDegree() 33410447Snilay@cs.wisc.edu { 33510447Snilay@cs.wisc.edu // Get properties 33610447Snilay@cs.wisc.edu unsigned int number_rings = getGenProperties()->get("InBits"); 33710447Snilay@cs.wisc.edu 33810447Snilay@cs.wisc.edu // Get tech model parameters 33910447Snilay@cs.wisc.edu double R = getTechModel()->get("Ring->Radius"); 34010447Snilay@cs.wisc.edu double n_g = getTechModel()->get("Ring->GroupIndex"); 34110447Snilay@cs.wisc.edu // This can actually be derived if we know thermo-optic coefficient (delta n / delta T) 34210447Snilay@cs.wisc.edu double sigma_r_local = getTechModel()->get("Ring->LocalVariationSigma"); 34310447Snilay@cs.wisc.edu 34410447Snilay@cs.wisc.edu // Get constants 34510447Snilay@cs.wisc.edu double c = Constants::c; 34610447Snilay@cs.wisc.edu double pi = Constants::pi; 34710447Snilay@cs.wisc.edu 34810447Snilay@cs.wisc.edu // Calculates the degree of bit re-order multiplexing needed for bit-reshuffling backend 34910447Snilay@cs.wisc.edu // Bit reshuffling tuning is largely unaffected by sigma_r_systematic. However, sigma_r_local 35010447Snilay@cs.wisc.edu // Can potentially throw each ring to a channel several channels away. This just calculates 35110447Snilay@cs.wisc.edu // the degree of bit reorder muxing needed to realign bits in the correct order 35210447Snilay@cs.wisc.edu 35310447Snilay@cs.wisc.edu // Setup calculations 35410447Snilay@cs.wisc.edu double L = 2 * pi * R; // Optical length 35510447Snilay@cs.wisc.edu double FSR = c / (n_g * L); // Free spectral range 35610447Snilay@cs.wisc.edu double freq_sep = FSR / number_rings; // Channel separation 35710447Snilay@cs.wisc.edu // Using 4 sigmas as the worst re-ordering case (must double to get both sides) 35810447Snilay@cs.wisc.edu unsigned int worst_case_channels = (unsigned int)ceil(2.0 * 4.0 * sigma_r_local / freq_sep); 35910447Snilay@cs.wisc.edu 36010447Snilay@cs.wisc.edu return worst_case_channels; 36110447Snilay@cs.wisc.edu } 36210447Snilay@cs.wisc.edu 36310447Snilay@cs.wisc.edu} // namespace DSENT 36410447Snilay@cs.wisc.edu 365