SRC/rr_graph_indexed_data.c

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#include <math.h>               /* Needed only for sqrt call (remove if sqrt removed) */
#include "util.h"
#include "vpr_types.h"
#include "globals.h"
#include "rr_graph_util.h"
#include "rr_graph2.h"
#include "rr_graph_indexed_data.h"


/******************* Subroutines local to this module ************************/

static void load_rr_indexed_data_base_costs(int nodes_per_chan,
                                            t_ivec *** rr_node_indices,
                                            enum e_base_cost_type
                                            base_cost_type,
                                            int wire_to_ipin_switch);

static float get_delay_normalization_fac(int nodes_per_chan,
                                         t_ivec *** rr_node_indices);

static float get_average_opin_delay(t_ivec *** rr_node_indices,
                                    int nodes_per_chan);

static void load_rr_indexed_data_T_values(int index_start,
                                          int num_indices_to_load,
                                          t_rr_type rr_type,
                                          int nodes_per_chan,
                                          t_ivec *** rr_node_indices,
                                          t_segment_inf * segment_inf);



/******************** Subroutine definitions *********************************/

/* Allocates the rr_indexed_data array and loads it with appropriate values. *
 * It currently stores the segment type (or OPEN if the index doesn't        *
 * correspond to an CHANX or CHANY type), the base cost of nodes of that     *
 * type, and some info to allow rapid estimates of time to get to a target   *
 * to be computed by the router.                                             *
 *
 * Right now all SOURCES have the same base cost; and similarly there's only *
 * one base cost for each of SINKs, OPINs, and IPINs (four total).  This can *
 * be changed just by allocating more space in the array below and changing  *
 * the cost_index values for these rr_nodes, if you want to make some pins   *
 * etc. more expensive than others.  I give each segment type in an          *
 * x-channel its own cost_index, and each segment type in a y-channel its    *
 * own cost_index.                                                           */
void
alloc_and_load_rr_indexed_data(IN t_segment_inf * segment_inf,
                               IN int num_segment,
                               IN t_ivec *** rr_node_indices,
                               IN int nodes_per_chan,
                               int wire_to_ipin_switch,
                               enum e_base_cost_type base_cost_type)
{

    int iseg, length, i, index;

    num_rr_indexed_data = CHANX_COST_INDEX_START + (2 * num_segment);
    rr_indexed_data = (t_rr_indexed_data *) my_malloc(num_rr_indexed_data *
                                                      sizeof
                                                      (t_rr_indexed_data));

    /* For rr_types that aren't CHANX or CHANY, base_cost is valid, but most     *
     * * other fields are invalid.  For IPINs, the T_linear field is also valid;   *
     * * all other fields are invalid.  For SOURCES, SINKs and OPINs, all fields   *
     * * other than base_cost are invalid. Mark invalid fields as OPEN for safety. */

    for(i = SOURCE_COST_INDEX; i <= IPIN_COST_INDEX; i++)
        {
            rr_indexed_data[i].ortho_cost_index = OPEN;
            rr_indexed_data[i].seg_index = OPEN;
            rr_indexed_data[i].inv_length = OPEN;
            rr_indexed_data[i].T_linear = OPEN;
            rr_indexed_data[i].T_quadratic = OPEN;
            rr_indexed_data[i].C_load = OPEN;
        }

    rr_indexed_data[IPIN_COST_INDEX].T_linear =
        switch_inf[wire_to_ipin_switch].Tdel;

    /* X-directed segments. */

    for(iseg = 0; iseg < num_segment; iseg++)
        {
            index = CHANX_COST_INDEX_START + iseg;

            rr_indexed_data[index].ortho_cost_index = index + num_segment;

            if(segment_inf[iseg].longline)
                length = nx;
            else
                length = min(segment_inf[iseg].length, nx);


            rr_indexed_data[index].inv_length = 1. / length;
            rr_indexed_data[index].seg_index = iseg;
        }

    load_rr_indexed_data_T_values(CHANX_COST_INDEX_START, num_segment,
                                  CHANX, nodes_per_chan, rr_node_indices,
                                  segment_inf);

    /* Y-directed segments. */

    for(iseg = 0; iseg < num_segment; iseg++)
        {
            index = CHANX_COST_INDEX_START + num_segment + iseg;

            rr_indexed_data[index].ortho_cost_index = index - num_segment;

            if(segment_inf[iseg].longline)
                length = ny;
            else
                length = min(segment_inf[iseg].length, ny);

            rr_indexed_data[index].inv_length = 1. / length;
            rr_indexed_data[index].seg_index = iseg;
        }

    load_rr_indexed_data_T_values((CHANX_COST_INDEX_START + num_segment),
                                  num_segment, CHANY, nodes_per_chan,
                                  rr_node_indices, segment_inf);

    load_rr_indexed_data_base_costs(nodes_per_chan, rr_node_indices,
                                    base_cost_type, wire_to_ipin_switch);

}


static void
load_rr_indexed_data_base_costs(int nodes_per_chan,
                                t_ivec *** rr_node_indices,
                                enum e_base_cost_type base_cost_type,
                                int wire_to_ipin_switch)
{

/* Loads the base_cost member of rr_indexed_data according to the specified *
 * base_cost_type.                                                          */

    float delay_normalization_fac;
    int index;

    if(base_cost_type == DELAY_NORMALIZED)
        {
            delay_normalization_fac =
                get_delay_normalization_fac(nodes_per_chan, rr_node_indices);
        }
    else
        {
            delay_normalization_fac = 1.;
        }

    if(base_cost_type == DEMAND_ONLY || base_cost_type == DELAY_NORMALIZED)
        {
            rr_indexed_data[SOURCE_COST_INDEX].base_cost =
                delay_normalization_fac;
            rr_indexed_data[SINK_COST_INDEX].base_cost = 0.;
            rr_indexed_data[OPIN_COST_INDEX].base_cost =
                delay_normalization_fac;

#ifndef SPEC
            rr_indexed_data[IPIN_COST_INDEX].base_cost =
                0.95 * delay_normalization_fac;
#else /* Avoid roundoff for SPEC */
            rr_indexed_data[IPIN_COST_INDEX].base_cost =
                delay_normalization_fac;
#endif
        }

    else if(base_cost_type == INTRINSIC_DELAY)
        {
            rr_indexed_data[SOURCE_COST_INDEX].base_cost = 0.;
            rr_indexed_data[SINK_COST_INDEX].base_cost = 0.;
            rr_indexed_data[OPIN_COST_INDEX].base_cost =
                get_average_opin_delay(rr_node_indices, nodes_per_chan);
            rr_indexed_data[IPIN_COST_INDEX].base_cost =
                switch_inf[wire_to_ipin_switch].Tdel;
        }

/* Load base costs for CHANX and CHANY segments */

    for(index = CHANX_COST_INDEX_START; index < num_rr_indexed_data; index++)
        {
            if(base_cost_type == INTRINSIC_DELAY)
                rr_indexed_data[index].base_cost =
                    rr_indexed_data[index].T_linear +
                    rr_indexed_data[index].T_quadratic;
            else
/*       rr_indexed_data[index].base_cost = delay_normalization_fac /
                                    rr_indexed_data[index].inv_length;  */

                rr_indexed_data[index].base_cost = delay_normalization_fac;
/*       rr_indexed_data[index].base_cost = delay_normalization_fac *
                  sqrt (1. / rr_indexed_data[index].inv_length);  */
/*       rr_indexed_data[index].base_cost = delay_normalization_fac *
                  (1. + 1. / rr_indexed_data[index].inv_length);  */
        }

/* Save a copy of the base costs -- if dynamic costing is used by the     * 
 * router, the base_cost values will get changed all the time and being   *
 * able to restore them from a saved version is useful.                   */

    for(index = 0; index < num_rr_indexed_data; index++)
        {
            rr_indexed_data[index].saved_base_cost =
                rr_indexed_data[index].base_cost;
        }
}


static float
get_delay_normalization_fac(int nodes_per_chan,
                            t_ivec *** rr_node_indices)
{

/* Returns the average delay to go 1 FB distance along a wire.  */

    const int clb_dist = 3;     /* Number of CLBs I think the average conn. goes. */

    int inode, itrack, cost_index;
    float Tdel, Tdel_sum, frac_num_seg;

    Tdel_sum = 0.;

    for(itrack = 0; itrack < nodes_per_chan; itrack++)
        {
            inode =
                get_rr_node_index((nx + 1) / 2, (ny + 1) / 2, CHANX, itrack,
                                  rr_node_indices);
            cost_index = rr_node[inode].cost_index;
            frac_num_seg = clb_dist * rr_indexed_data[cost_index].inv_length;
            Tdel = frac_num_seg * rr_indexed_data[cost_index].T_linear +
                frac_num_seg * frac_num_seg *
                rr_indexed_data[cost_index].T_quadratic;
            Tdel_sum += Tdel / (float)clb_dist;
        }

    for(itrack = 0; itrack < nodes_per_chan; itrack++)
        {
            inode =
                get_rr_node_index((nx + 1) / 2, (ny + 1) / 2, CHANY, itrack,
                                  rr_node_indices);
            cost_index = rr_node[inode].cost_index;
            frac_num_seg = clb_dist * rr_indexed_data[cost_index].inv_length;
            Tdel = frac_num_seg * rr_indexed_data[cost_index].T_linear +
                frac_num_seg * frac_num_seg *
                rr_indexed_data[cost_index].T_quadratic;
            Tdel_sum += Tdel / (float)clb_dist;
        }

    return (Tdel_sum / (2. * nodes_per_chan));
}


static float
get_average_opin_delay(t_ivec *** rr_node_indices,
                       int nodes_per_chan)
{

/* Returns the average delay from an OPIN to a wire in an adjacent channel. */
    /* RESEARCH TODO: Got to think if this heuristic needs to change for hetero, right now, I'll calculate
     * the average delay of non-IO blocks */
    int inode, ipin, iclass, iedge, itype, num_edges, to_switch, to_node,
        num_conn;
    float Cload, Tdel;

    Tdel = 0.;
    num_conn = 0;
    for(itype = 0;
        itype < num_types && &type_descriptors[itype] != IO_TYPE; itype++)
        {
            for(ipin = 0; ipin < type_descriptors[itype].num_pins; ipin++)
                {
                    iclass = type_descriptors[itype].pin_class[ipin];
                    if(type_descriptors[itype].class_inf[iclass].type ==
                       DRIVER)
                        {       /* OPIN */
                            inode =
                                get_rr_node_index((nx + 1) / 2, (ny + 1) / 2,
                                                  OPIN, ipin,
                                                  rr_node_indices);
                            num_edges = rr_node[inode].num_edges;

                            for(iedge = 0; iedge < num_edges; iedge++)
                                {
                                    to_node = rr_node[inode].edges[iedge];
                                    to_switch =
                                        rr_node[inode].switches[iedge];
                                    Cload = rr_node[to_node].C;
                                    Tdel +=
                                        Cload * switch_inf[to_switch].R +
                                        switch_inf[to_switch].Tdel;
                                    num_conn++;
                                }
                        }
                }
        }

    Tdel /= (float)num_conn;
    return (Tdel);
}


static void
load_rr_indexed_data_T_values(int index_start,
                              int num_indices_to_load,
                              t_rr_type rr_type,
                              int nodes_per_chan,
                              t_ivec *** rr_node_indices,
                              t_segment_inf * segment_inf)
{

/* Loads the average propagation times through segments of each index type  *
 * for either all CHANX segment types or all CHANY segment types.  It does  *
 * this by looking at all the segments in one channel in the middle of the  *
 * array and averaging the R and C values of all segments of the same type  *
 * and using them to compute average delay values for this type of segment. */

    int itrack, iseg, inode, cost_index, iswitch;
    float *C_total, *R_total;   /* [0..num_rr_indexed_data - 1] */
    int *num_nodes_of_index;    /* [0..num_rr_indexed_data - 1] */
    float Rnode, Cnode, Rsw, Tsw;

    num_nodes_of_index = (int *)my_calloc(num_rr_indexed_data, sizeof(int));
    C_total = (float *)my_calloc(num_rr_indexed_data, sizeof(float));
    R_total = (float *)my_calloc(num_rr_indexed_data, sizeof(float));

/* Get average C and R values for all the segments of this type in one      *
 * channel segment, near the middle of the array.                           */

    for(itrack = 0; itrack < nodes_per_chan; itrack++)
        {
            inode =
                get_rr_node_index((nx + 1) / 2, (ny + 1) / 2, rr_type, itrack,
                                  rr_node_indices);
            cost_index = rr_node[inode].cost_index;
            num_nodes_of_index[cost_index]++;
            C_total[cost_index] += rr_node[inode].C;
            R_total[cost_index] += rr_node[inode].R;
        }


    for(cost_index = index_start;
        cost_index < index_start + num_indices_to_load; cost_index++)
        {

            if(num_nodes_of_index[cost_index] == 0)
                {               /* Segments don't exist. */
                    rr_indexed_data[cost_index].T_linear = OPEN;
                    rr_indexed_data[cost_index].T_quadratic = OPEN;
                    rr_indexed_data[cost_index].C_load = OPEN;
                }
            else
                {
                    Rnode =
                        R_total[cost_index] / num_nodes_of_index[cost_index];
                    Cnode =
                        C_total[cost_index] / num_nodes_of_index[cost_index];
                    iseg = rr_indexed_data[cost_index].seg_index;
                    iswitch = segment_inf[iseg].wire_switch;
                    Rsw = switch_inf[iswitch].R;
                    Tsw = switch_inf[iswitch].Tdel;

                    if(switch_inf[iswitch].buffered)
                        {
                            rr_indexed_data[cost_index].T_linear =
                                Tsw + Rsw * Cnode + 0.5 * Rnode * Cnode;
                            rr_indexed_data[cost_index].T_quadratic = 0.;
                            rr_indexed_data[cost_index].C_load = 0.;
                        }
                    else
                        {       /* Pass transistor */
                            rr_indexed_data[cost_index].C_load = Cnode;

                            /* See Dec. 23, 1997 notes for deriviation of formulae. */

                            rr_indexed_data[cost_index].T_linear =
                                Tsw + 0.5 * Rsw * Cnode;
                            rr_indexed_data[cost_index].T_quadratic =
                                (Rsw + Rnode) * 0.5 * Cnode;
                        }
                }
        }

    free(num_nodes_of_index);
    free(C_total);
    free(R_total);
}

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