110448Snilay@cs.wisc.edu/* Copyright (c) 2012 Massachusetts Institute of Technology 210448Snilay@cs.wisc.edu * 310448Snilay@cs.wisc.edu * Permission is hereby granted, free of charge, to any person obtaining a copy 410448Snilay@cs.wisc.edu * of this software and associated documentation files (the "Software"), to deal 510448Snilay@cs.wisc.edu * in the Software without restriction, including without limitation the rights 610448Snilay@cs.wisc.edu * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 710448Snilay@cs.wisc.edu * copies of the Software, and to permit persons to whom the Software is 810448Snilay@cs.wisc.edu * furnished to do so, subject to the following conditions: 910448Snilay@cs.wisc.edu * 1010448Snilay@cs.wisc.edu * The above copyright notice and this permission notice shall be included in 1110448Snilay@cs.wisc.edu * all copies or substantial portions of the Software. 1210448Snilay@cs.wisc.edu * 1310448Snilay@cs.wisc.edu * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 1410448Snilay@cs.wisc.edu * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 1510448Snilay@cs.wisc.edu * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 1610448Snilay@cs.wisc.edu * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 1710448Snilay@cs.wisc.edu * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 1810448Snilay@cs.wisc.edu * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 1910448Snilay@cs.wisc.edu * THE SOFTWARE. 2010448Snilay@cs.wisc.edu */ 2110448Snilay@cs.wisc.edu 2210447Snilay@cs.wisc.edu#include "model/optical/OpticalLinkBackendTx.h" 2310447Snilay@cs.wisc.edu 2410447Snilay@cs.wisc.edu#include "util/Constants.h" 2510447Snilay@cs.wisc.edu#include "model/PortInfo.h" 2610447Snilay@cs.wisc.edu#include "model/TransitionInfo.h" 2710447Snilay@cs.wisc.edu#include "model/EventInfo.h" 2810447Snilay@cs.wisc.edu#include "model/electrical/MuxTreeSerializer.h" 2910447Snilay@cs.wisc.edu#include "model/electrical/BarrelShifter.h" 3010447Snilay@cs.wisc.edu#include "model/electrical/Multiplexer.h" 3110447Snilay@cs.wisc.edu#include <cmath> 3210447Snilay@cs.wisc.edu 3310447Snilay@cs.wisc.edunamespace DSENT 3410447Snilay@cs.wisc.edu{ 3510447Snilay@cs.wisc.edu // TODO: Kind of don't like the way thermal tuning is written here. Maybe will switch 3610447Snilay@cs.wisc.edu // to curve fitting the CICC paper, which uses results from a monte-carlo sim 3710447Snilay@cs.wisc.edu 3810447Snilay@cs.wisc.edu OpticalLinkBackendTx::OpticalLinkBackendTx(const String& instance_name_, const TechModel* tech_model_) 3910447Snilay@cs.wisc.edu : ElectricalModel(instance_name_, tech_model_) 4010447Snilay@cs.wisc.edu { 4110447Snilay@cs.wisc.edu initParameters(); 4210447Snilay@cs.wisc.edu initProperties(); 4310447Snilay@cs.wisc.edu } 4410447Snilay@cs.wisc.edu 4510447Snilay@cs.wisc.edu OpticalLinkBackendTx::~OpticalLinkBackendTx() 4610447Snilay@cs.wisc.edu {} 4710447Snilay@cs.wisc.edu 4810447Snilay@cs.wisc.edu void OpticalLinkBackendTx::initParameters() 4910447Snilay@cs.wisc.edu { 5010447Snilay@cs.wisc.edu addParameterName("InBits"); 5110447Snilay@cs.wisc.edu addParameterName("CoreDataRate"); 5210447Snilay@cs.wisc.edu addParameterName("LinkDataRate"); 5310447Snilay@cs.wisc.edu addParameterName("RingTuningMethod"); 5410447Snilay@cs.wisc.edu addParameterName("BitDuplicate"); 5510447Snilay@cs.wisc.edu return; 5610447Snilay@cs.wisc.edu } 5710447Snilay@cs.wisc.edu 5810447Snilay@cs.wisc.edu void OpticalLinkBackendTx::initProperties() 5910447Snilay@cs.wisc.edu { 6010447Snilay@cs.wisc.edu return; 6110447Snilay@cs.wisc.edu } 6210447Snilay@cs.wisc.edu 6310447Snilay@cs.wisc.edu void OpticalLinkBackendTx::constructModel() 6410447Snilay@cs.wisc.edu { 6510447Snilay@cs.wisc.edu unsigned int in_bits = getParameter("InBits"); 6610447Snilay@cs.wisc.edu double core_data_rate = getParameter("CoreDataRate"); 6710447Snilay@cs.wisc.edu double link_data_rate = getParameter("LinkDataRate"); 6810447Snilay@cs.wisc.edu const String& tuning_method = getParameter("RingTuningMethod");; 6910447Snilay@cs.wisc.edu bool bit_duplicate = getParameter("BitDuplicate"); 7010447Snilay@cs.wisc.edu 7110447Snilay@cs.wisc.edu // Calculate serialization ratio 7210447Snilay@cs.wisc.edu unsigned int serialization_ratio = (unsigned int) floor(link_data_rate / core_data_rate); 7310447Snilay@cs.wisc.edu ASSERT(serialization_ratio == link_data_rate / core_data_rate, 7410447Snilay@cs.wisc.edu "[Error] " + getInstanceName() + " -> Cannot have non-integer serialization ratios " + 7510447Snilay@cs.wisc.edu "(" + (String) (core_data_rate / link_data_rate) + ")!"); 7610447Snilay@cs.wisc.edu 7710447Snilay@cs.wisc.edu // Calculate output width 7810447Snilay@cs.wisc.edu ASSERT(floor((double) in_bits / serialization_ratio) == (double) in_bits / serialization_ratio, 7910447Snilay@cs.wisc.edu "[Error] " + getInstanceName() + " -> Input width (" + (String) in_bits + ") " + 8010447Snilay@cs.wisc.edu "must be a multiple of the serialization ratio (" + (String) serialization_ratio + ")!"); 8110447Snilay@cs.wisc.edu unsigned int out_bits = in_bits / serialization_ratio; 8210447Snilay@cs.wisc.edu 8310447Snilay@cs.wisc.edu getGenProperties()->set("SerializationRatio", serialization_ratio); 8410447Snilay@cs.wisc.edu getGenProperties()->set("OutBits", out_bits); 8510447Snilay@cs.wisc.edu 8610447Snilay@cs.wisc.edu // Create ports 8710447Snilay@cs.wisc.edu createInputPort("In", makeNetIndex(0, in_bits-1)); 8810447Snilay@cs.wisc.edu createInputPort("LinkCK"); 8910447Snilay@cs.wisc.edu createOutputPort("Out", makeNetIndex(0, out_bits-1)); 9010447Snilay@cs.wisc.edu 9110447Snilay@cs.wisc.edu //Create energy, power, and area results 9210447Snilay@cs.wisc.edu createElectricalResults(); 9310447Snilay@cs.wisc.edu // Create ring heating power cost 9410447Snilay@cs.wisc.edu addNddPowerResult(new AtomicResult("RingTuning")); 9510447Snilay@cs.wisc.edu // Create process bits event 9610447Snilay@cs.wisc.edu createElectricalEventResult("ProcessBits"); 9710447Snilay@cs.wisc.edu getEventInfo("ProcessBits")->setTransitionInfo("LinkCK", TransitionInfo(0.0, (double) serialization_ratio / 2.0, 0.0)); 9810447Snilay@cs.wisc.edu // Set conditions during idle state 9910447Snilay@cs.wisc.edu getEventInfo("Idle")->setStaticTransitionInfos(); 10010447Snilay@cs.wisc.edu getEventInfo("Idle")->setTransitionInfo("LinkCK", TransitionInfo(0.0, (double) serialization_ratio / 2.0, 0.0)); 10110447Snilay@cs.wisc.edu 10210447Snilay@cs.wisc.edu // Create serializer 10310447Snilay@cs.wisc.edu const String& serializer_name = "Serializer"; 10410447Snilay@cs.wisc.edu MuxTreeSerializer* serializer = new MuxTreeSerializer(serializer_name, getTechModel()); 10510447Snilay@cs.wisc.edu serializer->setParameter("InBits", in_bits); 10610447Snilay@cs.wisc.edu serializer->setParameter("InDataRate", core_data_rate); 10710447Snilay@cs.wisc.edu serializer->setParameter("OutDataRate", link_data_rate); 10810447Snilay@cs.wisc.edu serializer->setParameter("BitDuplicate", bit_duplicate); 10910447Snilay@cs.wisc.edu serializer->construct(); 11010447Snilay@cs.wisc.edu 11110447Snilay@cs.wisc.edu addSubInstances(serializer, 1.0); 11210447Snilay@cs.wisc.edu addElectricalSubResults(serializer, 1.0); 11310447Snilay@cs.wisc.edu getEventResult("ProcessBits")->addSubResult(serializer->getEventResult("Serialize"), serializer_name, 1.0); 11410447Snilay@cs.wisc.edu 11510447Snilay@cs.wisc.edu if ((tuning_method == "ThermalWithBitReshuffle") || (tuning_method == "ElectricalAssistWithBitReshuffle")) 11610447Snilay@cs.wisc.edu { 11710447Snilay@cs.wisc.edu // If a bit reshuffling backend is present, create the reshuffling backend 11810447Snilay@cs.wisc.edu unsigned int reorder_degree = getBitReorderDegree(); 11910447Snilay@cs.wisc.edu 12010447Snilay@cs.wisc.edu // Create intermediate nets 12110447Snilay@cs.wisc.edu createNet("SerializerIn", makeNetIndex(0, in_bits-1)); 12210447Snilay@cs.wisc.edu createNet("ReorderIn", makeNetIndex(0, out_bits+reorder_degree-1)); 12310447Snilay@cs.wisc.edu assign("ReorderIn", makeNetIndex(out_bits, out_bits+reorder_degree-1), "ReorderIn", makeNetIndex(0, reorder_degree-1)); 12410447Snilay@cs.wisc.edu 12510447Snilay@cs.wisc.edu // Create barrelshifter 12610447Snilay@cs.wisc.edu unsigned int shift_index_min = (unsigned int)ceil(log2(serialization_ratio)); 12710447Snilay@cs.wisc.edu unsigned int shift_index_max = std::max(shift_index_min, (unsigned int) ceil(log2(in_bits)) - 1); 12810447Snilay@cs.wisc.edu 12910447Snilay@cs.wisc.edu // Remember some things 13010447Snilay@cs.wisc.edu getGenProperties()->set("ReorderDegree", reorder_degree); 13110447Snilay@cs.wisc.edu getGenProperties()->set("ShiftIndexMin", shift_index_min); 13210447Snilay@cs.wisc.edu getGenProperties()->set("ShiftIndexMax", shift_index_max); 13310447Snilay@cs.wisc.edu 13410447Snilay@cs.wisc.edu const String& barrel_shift_name = "BarrelShifter"; 13510447Snilay@cs.wisc.edu BarrelShifter* barrel_shift = new BarrelShifter(barrel_shift_name, getTechModel()); 13610447Snilay@cs.wisc.edu barrel_shift->setParameter("NumberBits", in_bits); 13710447Snilay@cs.wisc.edu barrel_shift->setParameter("ShiftIndexMax", shift_index_max); 13810447Snilay@cs.wisc.edu barrel_shift->setParameter("ShiftIndexMin", shift_index_min); 13910447Snilay@cs.wisc.edu barrel_shift->setParameter("BitDuplicate", bit_duplicate); 14010447Snilay@cs.wisc.edu barrel_shift->construct(); 14110447Snilay@cs.wisc.edu 14210447Snilay@cs.wisc.edu // Create bit reorder muxes 14310447Snilay@cs.wisc.edu const String& reorder_mux_name = "ReorderMux"; 14410447Snilay@cs.wisc.edu Multiplexer* reorder_mux = new Multiplexer(reorder_mux_name, getTechModel()); 14510447Snilay@cs.wisc.edu reorder_mux->setParameter("NumberBits", out_bits); 14610447Snilay@cs.wisc.edu reorder_mux->setParameter("NumberInputs", reorder_degree); 14710447Snilay@cs.wisc.edu reorder_mux->setParameter("BitDuplicate", bit_duplicate); 14810447Snilay@cs.wisc.edu reorder_mux->construct(); 14910447Snilay@cs.wisc.edu 15010447Snilay@cs.wisc.edu // Connect barrelshifter 15110447Snilay@cs.wisc.edu // TODO: Connect barrelshift shifts! 15210447Snilay@cs.wisc.edu portConnect(barrel_shift, "In", "In"); 15310447Snilay@cs.wisc.edu portConnect(barrel_shift, "Out", "SerializerIn"); 15410447Snilay@cs.wisc.edu 15510447Snilay@cs.wisc.edu // Connect serializer 15610447Snilay@cs.wisc.edu portConnect(serializer, "In", "SerializerIn"); 15710447Snilay@cs.wisc.edu portConnect(serializer, "Out", "ReorderIn", makeNetIndex(0, out_bits-1)); 15810447Snilay@cs.wisc.edu portConnect(serializer, "OutCK", "LinkCK"); 15910447Snilay@cs.wisc.edu 16010447Snilay@cs.wisc.edu // Connect bit reorder muxes 16110447Snilay@cs.wisc.edu // TODO: Connect re-order multiplex select signals! 16210447Snilay@cs.wisc.edu for (unsigned int i = 0; i < reorder_degree; i++) 16310447Snilay@cs.wisc.edu portConnect(reorder_mux, "In" + (String) i, "ReorderIn", makeNetIndex(i, i+out_bits-1)); 16410447Snilay@cs.wisc.edu portConnect(reorder_mux, "Out", "Out"); 16510447Snilay@cs.wisc.edu 16610447Snilay@cs.wisc.edu addSubInstances(barrel_shift, 1.0); 16710447Snilay@cs.wisc.edu addSubInstances(reorder_mux, 1.0); 16810447Snilay@cs.wisc.edu addElectricalSubResults(barrel_shift, 1.0); 16910447Snilay@cs.wisc.edu addElectricalSubResults(reorder_mux, 1.0); 17010447Snilay@cs.wisc.edu getEventResult("ProcessBits")->addSubResult(barrel_shift->getEventResult("BarrelShift"), barrel_shift_name, 1.0); 17110447Snilay@cs.wisc.edu getEventResult("ProcessBits")->addSubResult(reorder_mux->getEventResult("Mux"), reorder_mux_name, 1.0); // This happens multiple times 17210447Snilay@cs.wisc.edu } 17310447Snilay@cs.wisc.edu else if ((tuning_method == "FullThermal") || (tuning_method == "AthermalWithTrim")) 17410447Snilay@cs.wisc.edu { 17510447Snilay@cs.wisc.edu // If no bit reshuffling backend is present, then just connect serializer up 17610447Snilay@cs.wisc.edu portConnect(serializer, "In", "In"); 17710447Snilay@cs.wisc.edu portConnect(serializer, "Out", "Out"); 17810447Snilay@cs.wisc.edu portConnect(serializer, "OutCK", "LinkCK"); 17910447Snilay@cs.wisc.edu } 18010447Snilay@cs.wisc.edu else 18110447Snilay@cs.wisc.edu { 18210447Snilay@cs.wisc.edu ASSERT(false, "[Error] " + getInstanceName() + " -> Unknown ring tuning method '" + tuning_method + "'!"); 18310447Snilay@cs.wisc.edu } 18410447Snilay@cs.wisc.edu 18510447Snilay@cs.wisc.edu return; 18610447Snilay@cs.wisc.edu } 18710447Snilay@cs.wisc.edu 18810447Snilay@cs.wisc.edu void OpticalLinkBackendTx::updateModel() 18910447Snilay@cs.wisc.edu { 19010447Snilay@cs.wisc.edu // Update everyone 19110447Snilay@cs.wisc.edu Model::updateModel(); 19210447Snilay@cs.wisc.edu // Update ring tuning power 19310447Snilay@cs.wisc.edu getNddPowerResult("RingTuning")->setValue(getRingTuningPower()); 19410447Snilay@cs.wisc.edu return; 19510447Snilay@cs.wisc.edu } 19610447Snilay@cs.wisc.edu 19710447Snilay@cs.wisc.edu void OpticalLinkBackendTx::propagateTransitionInfo() 19810447Snilay@cs.wisc.edu { 19910447Snilay@cs.wisc.edu // Get parameters 20010447Snilay@cs.wisc.edu const String& tuning_method = getParameter("RingTuningMethod"); 20110447Snilay@cs.wisc.edu 20210447Snilay@cs.wisc.edu // Update the serializer 20310447Snilay@cs.wisc.edu if ((tuning_method == "ThermalWithBitReshuffle") || (tuning_method == "ElectricalAssistWithBitReshuffle")) 20410447Snilay@cs.wisc.edu { 20510447Snilay@cs.wisc.edu // Get generated properties 20610447Snilay@cs.wisc.edu unsigned int reorder_degree = getGenProperties()->get("ReorderDegree").toUInt(); 20710447Snilay@cs.wisc.edu unsigned int shift_index_min = getGenProperties()->get("ShiftIndexMin").toUInt(); 20810447Snilay@cs.wisc.edu unsigned int shift_index_max = getGenProperties()->get("ShiftIndexMax").toUInt(); 20910447Snilay@cs.wisc.edu 21010447Snilay@cs.wisc.edu // Update barrel shifter 21110447Snilay@cs.wisc.edu const String& barrel_shift_name = "BarrelShifter"; 21210447Snilay@cs.wisc.edu ElectricalModel* barrel_shift = (ElectricalModel*) getSubInstance(barrel_shift_name); 21310447Snilay@cs.wisc.edu propagatePortTransitionInfo(barrel_shift, "In", "In"); 21410447Snilay@cs.wisc.edu // Set shift transitions to be very low (since it is affected by slow temperature time constants) 21510447Snilay@cs.wisc.edu for (unsigned int i = shift_index_min; i <= shift_index_max; ++i) 21610447Snilay@cs.wisc.edu barrel_shift->getInputPort("Shift" + (String) i)->setTransitionInfo(TransitionInfo(0.499, 0.001, 0.499)); 21710447Snilay@cs.wisc.edu barrel_shift->use(); 21810447Snilay@cs.wisc.edu 21910447Snilay@cs.wisc.edu // Set serializer transition info 22010447Snilay@cs.wisc.edu ElectricalModel* serializer = (ElectricalModel*) getSubInstance("Serializer"); 22110447Snilay@cs.wisc.edu propagatePortTransitionInfo(serializer, "In", barrel_shift, "Out"); 22210447Snilay@cs.wisc.edu propagatePortTransitionInfo(serializer, "OutCK", "LinkCK"); 22310447Snilay@cs.wisc.edu serializer->use(); 22410447Snilay@cs.wisc.edu 22510447Snilay@cs.wisc.edu // Reorder mux shift select bits 22610447Snilay@cs.wisc.edu unsigned int reorder_sel_bits = (unsigned int)ceil(log2(reorder_degree)); 22710447Snilay@cs.wisc.edu 22810447Snilay@cs.wisc.edu // Reorder mux probabilities 22910447Snilay@cs.wisc.edu const String& reorder_mux_name = "ReorderMux"; 23010447Snilay@cs.wisc.edu ElectricalModel* reorder_mux = (ElectricalModel*) getSubInstance(reorder_mux_name); 23110447Snilay@cs.wisc.edu for (unsigned int i = 0; i < reorder_degree; ++i) 23210447Snilay@cs.wisc.edu propagatePortTransitionInfo(reorder_mux, "In" + (String) i, serializer, "Out"); 23310447Snilay@cs.wisc.edu // Set select transitions to be 0, since these are statically configured 23410447Snilay@cs.wisc.edu for (unsigned int i = 0; i < reorder_sel_bits; ++i) 23510447Snilay@cs.wisc.edu reorder_mux->getInputPort("Sel" + (String) i)->setTransitionInfo(TransitionInfo(0.5, 0.0, 0.5)); 23610447Snilay@cs.wisc.edu reorder_mux->use(); 23710447Snilay@cs.wisc.edu 23810447Snilay@cs.wisc.edu // Set output transition info 23910447Snilay@cs.wisc.edu propagatePortTransitionInfo("Out", reorder_mux, "Out"); 24010447Snilay@cs.wisc.edu } 24110447Snilay@cs.wisc.edu else if ((tuning_method == "FullThermal") || (tuning_method == "AthermalWithTrim")) 24210447Snilay@cs.wisc.edu { 24310447Snilay@cs.wisc.edu // Set serializer transition info 24410447Snilay@cs.wisc.edu ElectricalModel* serializer = (ElectricalModel*) getSubInstance("Serializer"); 24510447Snilay@cs.wisc.edu propagatePortTransitionInfo(serializer, "In", "In"); 24610447Snilay@cs.wisc.edu propagatePortTransitionInfo(serializer, "OutCK", "LinkCK"); 24710447Snilay@cs.wisc.edu serializer->use(); 24810447Snilay@cs.wisc.edu 24910447Snilay@cs.wisc.edu // Set output transition info 25010447Snilay@cs.wisc.edu propagatePortTransitionInfo("Out", serializer, "Out"); 25110447Snilay@cs.wisc.edu } 25210447Snilay@cs.wisc.edu 25310447Snilay@cs.wisc.edu return; 25410447Snilay@cs.wisc.edu } 25510447Snilay@cs.wisc.edu 25610447Snilay@cs.wisc.edu double OpticalLinkBackendTx::getRingTuningPower() 25710447Snilay@cs.wisc.edu { 25810447Snilay@cs.wisc.edu // Get properties 25910447Snilay@cs.wisc.edu const String& tuning_method = getParameter("RingTuningMethod");; 26010447Snilay@cs.wisc.edu unsigned int number_rings = getGenProperties()->get("OutBits"); 26110447Snilay@cs.wisc.edu 26210447Snilay@cs.wisc.edu // Get tech model parameters 26310447Snilay@cs.wisc.edu double R = getTechModel()->get("Ring->Radius"); 26410447Snilay@cs.wisc.edu double n_g = getTechModel()->get("Ring->GroupIndex"); 26510447Snilay@cs.wisc.edu double heating_efficiency = getTechModel()->get("Ring->HeatingEfficiency"); 26610447Snilay@cs.wisc.edu // This can actually be derived if we know thermo-optic coefficient (delta n / delta T) 26710447Snilay@cs.wisc.edu double tuning_efficiency = getTechModel()->get("Ring->TuningEfficiency"); 26810447Snilay@cs.wisc.edu double sigma_r_local = getTechModel()->get("Ring->LocalVariationSigma"); 26910447Snilay@cs.wisc.edu double sigma_r_systematic = getTechModel()->get("Ring->SystematicVariationSigma"); 27010447Snilay@cs.wisc.edu double T_max = getTechModel()->get("Ring->TemperatureMax"); 27110447Snilay@cs.wisc.edu double T_min = getTechModel()->get("Ring->TemperatureMin"); 27210447Snilay@cs.wisc.edu double T = getTechModel()->get("Temperature"); 27310447Snilay@cs.wisc.edu 27410447Snilay@cs.wisc.edu // Get constants 27510447Snilay@cs.wisc.edu double c = Constants::c; 27610447Snilay@cs.wisc.edu double pi = Constants::pi; 27710447Snilay@cs.wisc.edu 27810447Snilay@cs.wisc.edu double tuning_power = 0.0; 27910447Snilay@cs.wisc.edu 28010447Snilay@cs.wisc.edu if (tuning_method == "ThermalWithBitReshuffle") 28110447Snilay@cs.wisc.edu { 28210447Snilay@cs.wisc.edu // When an electrical backend is present, rings only have to tune to the nearest channel 28310447Snilay@cs.wisc.edu // This can be approximated as each ring tuning to something exactly 1 channel away 28410447Snilay@cs.wisc.edu 28510447Snilay@cs.wisc.edu // Setup calculations 28610447Snilay@cs.wisc.edu double L = 2 * pi * R; // Optical length 28710447Snilay@cs.wisc.edu double FSR = c / (n_g * L); // Free spectral range 28810447Snilay@cs.wisc.edu double freq_sep = FSR / number_rings; // Channel separation 28910447Snilay@cs.wisc.edu 29010447Snilay@cs.wisc.edu // Calculate tuning power 29110447Snilay@cs.wisc.edu tuning_power = number_rings * freq_sep / (tuning_efficiency * heating_efficiency); 29210447Snilay@cs.wisc.edu } 29310447Snilay@cs.wisc.edu else if (tuning_method == "ElectricalAssistWithBitReshuffle") 29410447Snilay@cs.wisc.edu { 29510447Snilay@cs.wisc.edu // Electrical assistance allows for a fraction of the tuning range to be 29610447Snilay@cs.wisc.edu // covered electrically. This is most pronounced when the tuning range is small, 29710447Snilay@cs.wisc.edu // such is the case when bit reshuffling is applied. The electrically 29810447Snilay@cs.wisc.edu // assisted part of it pretty much comes for free... 29910447Snilay@cs.wisc.edu 30010447Snilay@cs.wisc.edu // Get electrically tunable range 30110447Snilay@cs.wisc.edu double max_assist = getTechModel()->get("Ring->MaxElectricallyTunableFreq"); 30210447Snilay@cs.wisc.edu 30310447Snilay@cs.wisc.edu // Setup calculations 30410447Snilay@cs.wisc.edu double L = 2 * pi * R; // Optical length 30510447Snilay@cs.wisc.edu double FSR = c / (n_g * L); // Free spectral range 30610447Snilay@cs.wisc.edu double freq_sep = FSR / number_rings; // Channel separation 30710447Snilay@cs.wisc.edu double heating_range = std::max(0.0, freq_sep - max_assist); // The distance needed to bridge using heaters 30810447Snilay@cs.wisc.edu 30910447Snilay@cs.wisc.edu // Calculate tuning power, which is really only the power spent on heating since 31010447Snilay@cs.wisc.edu // distance tuned electrically is pretty much free 31110447Snilay@cs.wisc.edu tuning_power = number_rings * heating_range / (tuning_efficiency * heating_efficiency); 31210447Snilay@cs.wisc.edu } 31310447Snilay@cs.wisc.edu else if (tuning_method == "FullThermal") 31410447Snilay@cs.wisc.edu { 31510447Snilay@cs.wisc.edu // If there is no bit reshuffling backend, each ring must tune to an 31610447Snilay@cs.wisc.edu // absolute channel frequency. Since we can only heat rings (and not cool), 31710447Snilay@cs.wisc.edu // we can only red-shift (decrease frequency). Thus, a fabrication bias 31810447Snilay@cs.wisc.edu // must be applied such that under any process and temperature corner, the 31910447Snilay@cs.wisc.edu // ring resonance remains above channel resonance 32010447Snilay@cs.wisc.edu // I'll use 3 sigmas of sigma_r_local and sigma_r_systematic, and bias against 32110447Snilay@cs.wisc.edu // the full temperature range 32210447Snilay@cs.wisc.edu double fabrication_bias_freq = 3.0 * sqrt(pow(sigma_r_local, 2) + pow(sigma_r_systematic, 2)) + 32310447Snilay@cs.wisc.edu (T_max - T_min) * tuning_efficiency; 32410447Snilay@cs.wisc.edu 32510447Snilay@cs.wisc.edu // The local/systematic variations are 0 on average. Thus, the tuning distance can be calculated as 32610447Snilay@cs.wisc.edu double tuning_distance = fabrication_bias_freq - (T - T_min) * tuning_efficiency; 32710447Snilay@cs.wisc.edu 32810447Snilay@cs.wisc.edu // Tuning power needed is just the number of rings * tuning distance / (tuning and heating efficiencies) 32910447Snilay@cs.wisc.edu tuning_power = number_rings * tuning_distance / (tuning_efficiency * heating_efficiency); 33010447Snilay@cs.wisc.edu } 33110447Snilay@cs.wisc.edu else if (tuning_method == "AthermalWithTrim") 33210447Snilay@cs.wisc.edu { 33310447Snilay@cs.wisc.edu // Athermal! Each ring's process variations are trimmed! Everything is free! 33410447Snilay@cs.wisc.edu // Basically an ideal scenario 33510447Snilay@cs.wisc.edu tuning_power = 0; 33610447Snilay@cs.wisc.edu } 33710447Snilay@cs.wisc.edu else 33810447Snilay@cs.wisc.edu { 33910447Snilay@cs.wisc.edu ASSERT(false, "[Error] " + getInstanceName() + " -> Unknown ring tuning method '" + tuning_method + "'!"); 34010447Snilay@cs.wisc.edu } 34110447Snilay@cs.wisc.edu 34210447Snilay@cs.wisc.edu return tuning_power; 34310447Snilay@cs.wisc.edu } 34410447Snilay@cs.wisc.edu 34510447Snilay@cs.wisc.edu unsigned int OpticalLinkBackendTx::getBitReorderDegree() 34610447Snilay@cs.wisc.edu { 34710447Snilay@cs.wisc.edu // Get properties 34810447Snilay@cs.wisc.edu unsigned int number_rings = getGenProperties()->get("OutBits"); 34910447Snilay@cs.wisc.edu 35010447Snilay@cs.wisc.edu // Get tech model parameters 35110447Snilay@cs.wisc.edu double R = getTechModel()->get("Ring->Radius"); 35210447Snilay@cs.wisc.edu double n_g = getTechModel()->get("Ring->GroupIndex"); 35310447Snilay@cs.wisc.edu // This can actually be derived if we know thermo-optic coefficient (delta n / delta T) 35410447Snilay@cs.wisc.edu double sigma_r_local = getTechModel()->get("Ring->LocalVariationSigma"); 35510447Snilay@cs.wisc.edu 35610447Snilay@cs.wisc.edu // Get constants 35710447Snilay@cs.wisc.edu double c = Constants::c; 35810447Snilay@cs.wisc.edu double pi = Constants::pi; 35910447Snilay@cs.wisc.edu 36010447Snilay@cs.wisc.edu // Calculates the degree of bit re-order multiplexing needed for bit-reshuffling backend 36110447Snilay@cs.wisc.edu // Bit reshuffling tuning is largely unaffected by sigma_r_systematic. However, sigma_r_local 36210447Snilay@cs.wisc.edu // Can potentially throw each ring to a channel several channels away. This just calculates 36310447Snilay@cs.wisc.edu // the degree of bit reorder muxing needed to realign bits in the correct order 36410447Snilay@cs.wisc.edu 36510447Snilay@cs.wisc.edu // Setup calculations 36610447Snilay@cs.wisc.edu double L = 2 * pi * R; // Optical length 36710447Snilay@cs.wisc.edu double FSR = c / (n_g * L); // Free spectral range 36810447Snilay@cs.wisc.edu double freq_sep = FSR / number_rings; // Channel separation 36910447Snilay@cs.wisc.edu // Using 4 sigmas as the worst re-ordering case (must double to get both sides) 37010447Snilay@cs.wisc.edu unsigned int worst_case_channels = (unsigned int)ceil(2.0 * 4.0 * sigma_r_local / freq_sep); 37110447Snilay@cs.wisc.edu 37210447Snilay@cs.wisc.edu return worst_case_channels; 37310447Snilay@cs.wisc.edu } 37410447Snilay@cs.wisc.edu 37510447Snilay@cs.wisc.edu} // namespace DSENT 37610447Snilay@cs.wisc.edu 377