router.cc

/*------------------------------------------------------------
 *                              CACTI 6.5
 *         Copyright 2008 Hewlett-Packard Development Corporation
 *                         All Rights Reserved
 *
 * Permission to use, copy, and modify this software and its documentation is
 * hereby granted only under the following terms and conditions.  Both the
 * above copyright notice and this permission notice must appear in all copies
 * of the software, derivative works or modified versions, and any portions
 * thereof, and both notices must appear in supporting documentation.
 *
 * Users of this software agree to the terms and conditions set forth herein, and
 * hereby grant back to Hewlett-Packard Company and its affiliated companies ("HP")
 * a non-exclusive, unrestricted, royalty-free right and license under any changes, 
 * enhancements or extensions  made to the core functions of the software, including 
 * but not limited to those affording compatibility with other hardware or software
 * environments, but excluding applications which incorporate this software.
 * Users further agree to use their best efforts to return to HP any such changes,
 * enhancements or extensions that they make and inform HP of noteworthy uses of
 * this software.  Correspondence should be provided to HP at:
 *
 *                       Director of Intellectual Property Licensing
 *                       Office of Strategy and Technology
 *                       Hewlett-Packard Company
 *                       1501 Page Mill Road
 *                       Palo Alto, California  94304
 *
 * This software may be distributed (but not offered for sale or transferred
 * for compensation) to third parties, provided such third parties agree to
 * abide by the terms and conditions of this notice.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND HP DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL HP 
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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 *------------------------------------------------------------*/

#include "router.h"

Router::Router(
    double flit_size_,
    double vc_buf, /* vc size = vc_buffer_size * flit_size */
    double vc_c,
    TechnologyParameter::DeviceType *dt
    ):flit_size(flit_size_), deviceType(dt)
{
  vc_buffer_size = vc_buf;
  vc_count = vc_c;
  min_w_pmos = deviceType->n_to_p_eff_curr_drv_ratio*g_tp.min_w_nmos_;
  double technology = g_ip->F_sz_um;

  Vdd = dt->Vdd;

  /*Crossbar parameters. Transmisson gate is employed for connector*/
  NTtr = 10*technology*1e-6/2; /*Transmission gate's nmos tr. length*/
  PTtr = 20*technology*1e-6/2; /* pmos tr. length*/
  wt = 15*technology*1e-6/2; /*track width*/
  ht = 15*technology*1e-6/2; /*track height*/
  I = 5; /*Number of crossbar input ports*/
  O = 5; /*Number of crossbar output ports*/
  NTi = 12.5*technology*1e-6/2;
  PTi = 25*technology*1e-6/2;

  NTid = 60*technology*1e-6/2; //m
  PTid = 120*technology*1e-6/2; // m
  NTod = 60*technology*1e-6/2; // m
  PTod = 120*technology*1e-6/2; // m

  calc_router_parameters();
}

Router::~Router(){}


double //wire cap with triple spacing
Router::Cw3(double length) {
  Wire wc(g_ip->wt, length, 1, 3, 3);
  return (wc.wire_cap(length));
}

/*Function to calculate the gate capacitance*/
double 
Router::gate_cap(double w) {
  return (double) gate_C (w*1e6 /*u*/, 0);
}

/*Function to calculate the diffusion capacitance*/
double 
Router::diff_cap(double w, int type /*0 for n-mos and 1 for p-mos*/,
    double s /*number of stacking transistors*/) {
  return (double) drain_C_(w*1e6 /*u*/, type, (int) s, 1, g_tp.cell_h_def);
}


/*crossbar related functions */

// Model for simple transmission gate
double 
Router::transmission_buf_inpcap() {
  return diff_cap(NTtr, 0, 1)+diff_cap(PTtr, 1, 1);
}

double 
Router::transmission_buf_outcap() {
  return diff_cap(NTtr, 0, 1)+diff_cap(PTtr, 1, 1);
}

double 
Router::transmission_buf_ctrcap() {
  return gate_cap(NTtr)+gate_cap(PTtr);
}

double 
Router::crossbar_inpline() {
  return (Cw3(O*flit_size*wt) + O*transmission_buf_inpcap() + gate_cap(NTid) + 
      gate_cap(PTid) + diff_cap(NTid, 0, 1) + diff_cap(PTid, 1, 1));
}

double 
Router::crossbar_outline() {
  return (Cw3(I*flit_size*ht) + I*transmission_buf_outcap() + gate_cap(NTod) + 
      gate_cap(PTod) + diff_cap(NTod, 0, 1) + diff_cap(PTod, 1, 1));
}

double 
Router::crossbar_ctrline() {
  return (Cw3(0.5*O*flit_size*wt) + flit_size*transmission_buf_ctrcap() + 
      diff_cap(NTi, 0, 1) + diff_cap(PTi, 1, 1) + 
      gate_cap(NTi) + gate_cap(PTi));
}

double 
Router::tr_crossbar_power() {
  return (crossbar_inpline()*Vdd*Vdd*flit_size/2 + 
      crossbar_outline()*Vdd*Vdd*flit_size/2)*2;
}

void Router::buffer_stats() 
{
  DynamicParameter dyn_p;
  dyn_p.is_tag = false;
  dyn_p.num_subarrays = 1;
  dyn_p.num_mats = 1;
  dyn_p.Ndbl = 1;
  dyn_p.Ndwl = 1;
  dyn_p.Nspd = 1;
  dyn_p.deg_bl_muxing = 1;
  dyn_p.deg_senseamp_muxing_non_associativity = 1;
  dyn_p.Ndsam_lev_1 = 1;
  dyn_p.Ndsam_lev_2 = 1;
  dyn_p.number_addr_bits_mat = 8;
  dyn_p.number_way_select_signals_mat = 1;
  dyn_p.num_act_mats_hor_dir = 1;
  dyn_p.is_dram = false;
  dyn_p.V_b_sense = Vdd; // FIXME check power calc.
  dyn_p.ram_cell_tech_type = 
    dyn_p.num_r_subarray = (int) vc_buffer_size;
  dyn_p.num_c_subarray = (int) flit_size * (int) vc_count;
  dyn_p.num_mats_h_dir = 1;
  dyn_p.num_mats_v_dir = 1;
  dyn_p.num_do_b_subbank = (int)flit_size;
  dyn_p.num_do_b_mat = (int) flit_size;

  dyn_p.use_inp_params = 1;
  dyn_p.num_wr_ports = (unsigned int) vc_count;
  dyn_p.num_rd_ports = (unsigned int) vc_count;
  dyn_p.num_rw_ports = 0;
  dyn_p.num_se_rd_ports =0;
  dyn_p.out_w = (int) flit_size;


  dyn_p.cell.h = g_tp.sram.b_h + 2 * g_tp.wire_outside_mat.pitch * (dyn_p.num_wr_ports + 
      dyn_p.num_rw_ports - 1 + dyn_p.num_rd_ports);
  dyn_p.cell.w = g_tp.sram.b_w + 2 * g_tp.wire_outside_mat.pitch * (dyn_p.num_rw_ports - 1 + 
      (dyn_p.num_rd_ports - dyn_p.num_se_rd_ports) + 
      dyn_p.num_wr_ports) + g_tp.wire_outside_mat.pitch * dyn_p.num_se_rd_ports;

  Mat buff(dyn_p);
  buff.compute_delays(0);
  buff.compute_power_energy();
  buffer.power.readOp  = buff.power.readOp;
  buffer.power.writeOp = buffer.power.readOp; //FIXME
  buffer.area = buff.area;
}



  void
Router::cb_stats ()
{
  if (1) {
    Crossbar c_b(I, O, flit_size);
    c_b.compute_power();
    crossbar.delay = c_b.delay;
    crossbar.power.readOp.dynamic = c_b.power.readOp.dynamic;
    crossbar.power.readOp.leakage = c_b.power.readOp.leakage;
    crossbar.area = c_b.area;
  }
  else {
    crossbar.power.readOp.dynamic = tr_crossbar_power();
    crossbar.power.readOp.leakage = flit_size * I * O * cmos_Ileak(NTtr*g_tp.min_w_nmos_, 
        PTtr*min_w_pmos);
  }
}

void
Router::get_router_power()
{
  double M = .6; //network load
  /* calculate buffer stats */
  buffer_stats();

  /* calculate cross-bar stats */
  cb_stats();

  /* calculate arbiter stats */
  Arbiter vcarb(vc_count, flit_size, buffer.area.w);
  Arbiter cbarb(I, flit_size, crossbar.area.w);
  vcarb.compute_power();
  cbarb.compute_power();
  arbiter.power.readOp.dynamic = vcarb.power.readOp.dynamic * I +
    cbarb.power.readOp.dynamic * O;
  arbiter.power.readOp.leakage = vcarb.power.readOp.leakage * I +
    cbarb.power.readOp.leakage * O;

//  arb_stats();
  power.readOp.dynamic = (I*(buffer.power.readOp.dynamic*buffer.power.writeOp.dynamic) +
      crossbar.power.readOp.dynamic +
      arbiter.power.readOp.dynamic)*M;
}

  void
Router::get_router_delay ()
{
  FREQUENCY=5; // move this to config file --TODO
  cycle_time = (1/(double)FREQUENCY)*1e3; //ps
  delay = 4;
  max_cyc = 17 * g_tp.FO4; //s
  max_cyc *= 1e12; //ps
  if (cycle_time < max_cyc) {
    FREQUENCY = (1/max_cyc)*1e3; //GHz
  }
}

  void
Router::get_router_area()
{
  area.h = I*buffer.area.h;
  area.w = buffer.area.w+crossbar.area.w;
}

  void
Router::calc_router_parameters()
{
  /* calculate router frequency and pipeline cycles */
  get_router_delay();

  /* router power stats */
  get_router_power();

  /* area stats */
  get_router_area();
}

  void
Router::print_router()
{
  cout << "\n\nRouter stats:\n";
  cout << "\tMaximum possible network frequency - " << (1/max_cyc)*1e3 << "GHz\n";
  cout << "\tNetwork frequency - " << FREQUENCY <<" GHz\n";
  cout << "\tNo. of Virtual channels - " << vc_count << "\n";
  cout << "\tNo. of pipeline stages - " << delay << endl;
  cout << "\tLink bandwidth - " << flit_size << " (bits)\n";
  cout << "\tNo. of buffer entries per virtual channel -  "<< vc_buffer_size << "\n";
  cout << "\tSimple buffer access (Read) - " << buffer.power.readOp.dynamic * 1e9 <<" (nJ)\n";

  cout << "\tCross bar access energy - " << crossbar.power.readOp.dynamic * 1e9<<" (nJ)\n"; 
  cout << "\tArbiter access energy (VC arb + Crossbar arb) - "<<arbiter.power.readOp.dynamic * 1e9 <<" (nJ)\n"; 

}