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|
/*
* nextpnr -- Next Generation Place and Route
*
* Copyright (C) 2018 Clifford Wolf <clifford@symbioticeda.com>
* Copyright (C) 2018 David Shah <david@symbioticeda.com>
*
* Simulated annealing implementation based on arachne-pnr
* Copyright (C) 2015-2018 Cotton Seed
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include "placer1.h"
#include <algorithm>
#include <boost/lexical_cast.hpp>
#include <boost/range/adaptor/reversed.hpp>
#include <chrono>
#include <cmath>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <ostream>
#include <queue>
#include <set>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <vector>
#include "log.h"
#include "place_common.h"
#include "timing.h"
#include "util.h"
namespace std {
template <> struct hash<std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, std::size_t>>
{
std::size_t operator()(const std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, std::size_t> &idp) const noexcept
{
std::size_t seed = 0;
boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(idp.first));
boost::hash_combine(seed, hash<std::size_t>()(idp.second));
return seed;
}
};
} // namespace std
NEXTPNR_NAMESPACE_BEGIN
class SAPlacer
{
private:
struct BoundingBox
{
int x0 = 0, x1 = 0, y0 = 0, y1 = 0;
bool is_inside_inc(int x, int y) const { return x >= x0 && x <= x1 && y >= y0 && y <= y1; }
bool touches_bounds(int x, int y) const { return x == x0 || x == x1 || y == y0 || y == y1; }
wirelen_t hpwl() const { return wirelen_t((x1 - x0) + (y1 - y0)); }
};
public:
SAPlacer(Context *ctx, Placer1Cfg cfg) : ctx(ctx), cfg(cfg)
{
int num_bel_types = 0;
for (auto bel : ctx->getBels()) {
IdString type = ctx->getBelType(bel);
if (bel_types.find(type) == bel_types.end()) {
bel_types[type] = std::tuple<int, int>(num_bel_types++, 1);
} else {
std::get<1>(bel_types.at(type))++;
}
}
for (auto bel : ctx->getBels()) {
Loc loc = ctx->getBelLocation(bel);
IdString type = ctx->getBelType(bel);
int type_idx = std::get<0>(bel_types.at(type));
int type_cnt = std::get<1>(bel_types.at(type));
if (type_cnt < cfg.minBelsForGridPick)
loc.x = loc.y = 0;
if (int(fast_bels.size()) < type_idx + 1)
fast_bels.resize(type_idx + 1);
if (int(fast_bels.at(type_idx).size()) < (loc.x + 1))
fast_bels.at(type_idx).resize(loc.x + 1);
if (int(fast_bels.at(type_idx).at(loc.x).size()) < (loc.y + 1))
fast_bels.at(type_idx).at(loc.x).resize(loc.y + 1);
max_x = std::max(max_x, loc.x);
max_y = std::max(max_y, loc.y);
fast_bels.at(type_idx).at(loc.x).at(loc.y).push_back(bel);
}
diameter = std::max(max_x, max_y) + 1;
build_port_index();
}
~SAPlacer() {}
bool place()
{
log_break();
ctx->lock();
size_t placed_cells = 0;
// Initial constraints placer
for (auto &cell_entry : ctx->cells) {
CellInfo *cell = cell_entry.second.get();
auto loc = cell->attrs.find(ctx->id("BEL"));
if (loc != cell->attrs.end()) {
std::string loc_name = loc->second;
BelId bel = ctx->getBelByName(ctx->id(loc_name));
if (bel == BelId()) {
log_error("No Bel named \'%s\' located for "
"this chip (processing BEL attribute on \'%s\')\n",
loc_name.c_str(), cell->name.c_str(ctx));
}
IdString bel_type = ctx->getBelType(bel);
if (bel_type != cell->type) {
log_error("Bel \'%s\' of type \'%s\' does not match cell "
"\'%s\' of type \'%s\'\n",
loc_name.c_str(), bel_type.c_str(ctx), cell->name.c_str(ctx), cell->type.c_str(ctx));
}
if (!ctx->isValidBelForCell(cell, bel)) {
log_error("Bel \'%s\' of type \'%s\' is not valid for cell "
"\'%s\' of type \'%s\'\n",
loc_name.c_str(), bel_type.c_str(ctx), cell->name.c_str(ctx), cell->type.c_str(ctx));
}
auto bound_cell = ctx->getBoundBelCell(bel);
if (bound_cell) {
log_error("Cell \'%s\' cannot be bound to bel \'%s\' since it is already bound to cell \'%s\'\n",
cell->name.c_str(ctx), loc_name.c_str(), bound_cell->name.c_str(ctx));
}
ctx->bindBel(bel, cell, STRENGTH_USER);
locked_bels.insert(bel);
placed_cells++;
}
}
int constr_placed_cells = placed_cells;
log_info("Placed %d cells based on constraints.\n", int(placed_cells));
ctx->yield();
// Sort to-place cells for deterministic initial placement
std::vector<CellInfo *> autoplaced;
std::vector<CellInfo *> chain_basis;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->bel == BelId()) {
autoplaced.push_back(cell.second.get());
}
}
std::sort(autoplaced.begin(), autoplaced.end(), [](CellInfo *a, CellInfo *b) { return a->name < b->name; });
ctx->shuffle(autoplaced);
auto iplace_start = std::chrono::high_resolution_clock::now();
// Place cells randomly initially
log_info("Creating initial placement for remaining %d cells.\n", int(autoplaced.size()));
for (auto cell : autoplaced) {
place_initial(cell);
placed_cells++;
if ((placed_cells - constr_placed_cells) % 500 == 0)
log_info(" initial placement placed %d/%d cells\n", int(placed_cells - constr_placed_cells),
int(autoplaced.size()));
}
if ((placed_cells - constr_placed_cells) % 500 != 0)
log_info(" initial placement placed %d/%d cells\n", int(placed_cells - constr_placed_cells),
int(autoplaced.size()));
if (cfg.budgetBased && ctx->slack_redist_iter > 0)
assign_budget(ctx);
ctx->yield();
auto iplace_end = std::chrono::high_resolution_clock::now();
log_info("Initial placement time %.02fs\n", std::chrono::duration<float>(iplace_end - iplace_start).count());
auto saplace_start = std::chrono::high_resolution_clock::now();
log_info("Running simulated annealing placer.\n");
// Invoke timing analysis to obtain criticalities
if (!cfg.budgetBased)
get_criticalities(ctx, &net_crit);
// Calculate costs after initial placement
setup_costs();
curr_wirelen_cost = total_wirelen_cost();
curr_timing_cost = total_timing_cost();
last_wirelen_cost = curr_wirelen_cost;
last_timing_cost = curr_timing_cost;
wirelen_t avg_wirelen = curr_wirelen_cost;
wirelen_t min_wirelen = curr_wirelen_cost;
int n_no_progress = 0;
temp = 1;
// Main simulated annealing loop
for (int iter = 1;; iter++) {
n_move = n_accept = 0;
improved = false;
if (iter % 5 == 0 || iter == 1)
log_info(" at iteration #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f\n",
iter, temp, double(curr_timing_cost), double(curr_wirelen_cost));
for (int m = 0; m < 15; ++m) {
// Loop through all automatically placed cells
for (auto cell : autoplaced) {
// Find another random Bel for this cell
BelId try_bel = random_bel_for_cell(cell);
// If valid, try and swap to a new position and see if
// the new position is valid/worthwhile
if (try_bel != BelId() && try_bel != cell->bel)
try_swap_position(cell, try_bel);
}
// Also try swapping chains, if applicable
for (auto cb : chain_basis) {
Loc chain_base_loc = ctx->getBelLocation(cb->bel);
BelId try_base = random_bel_for_cell(cb, chain_base_loc.z);
if (try_base != BelId() && try_base != cb->bel)
try_swap_chain(cb, try_base);
}
}
if (curr_wirelen_cost < min_wirelen) {
min_wirelen = curr_wirelen_cost;
improved = true;
}
// Heuristic to improve placement on the 8k
if (improved)
n_no_progress = 0;
else
n_no_progress++;
if (temp <= 1e-7 && n_no_progress >= 5) {
log_info(" at iteration #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f \n",
iter, temp, double(curr_timing_cost), double(curr_wirelen_cost));
break;
}
double Raccept = double(n_accept) / double(n_move);
int M = std::max(max_x, max_y) + 1;
double upper = 0.6, lower = 0.4;
if (ctx->verbose)
log("iter #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f, dia = %d, Ra = %.02f \n",
iter, temp, double(curr_timing_cost), double(curr_wirelen_cost), diameter, Raccept);
if (curr_wirelen_cost < 0.95 * avg_wirelen && curr_wirelen_cost > 0) {
avg_wirelen = 0.8 * avg_wirelen + 0.2 * curr_wirelen_cost;
} else {
if (Raccept >= 0.8) {
temp *= 0.7;
} else if (Raccept > upper) {
if (diameter < M)
diameter++;
else
temp *= 0.9;
} else if (Raccept > lower) {
temp *= 0.95;
} else {
// Raccept < 0.3
if (diameter > 1)
diameter--;
else
temp *= 0.8;
}
}
// Once cooled below legalise threshold, run legalisation and start requiring
// legal moves only
if (temp < legalise_temp && require_legal) {
if (legalise_relative_constraints(ctx)) {
// Only increase temperature if something was moved
autoplaced.clear();
chain_basis.clear();
for (auto cell : sorted(ctx->cells)) {
if (cell.second->belStrength <= STRENGTH_STRONG && cell.second->constr_parent == nullptr && !cell.second->constr_children.empty())
chain_basis.push_back(cell.second);
else if (cell.second->belStrength < STRENGTH_STRONG)
autoplaced.push_back(cell.second);
}
temp = post_legalise_temp;
diameter = std::min<int>(M, diameter * post_legalise_dia_scale);
ctx->shuffle(autoplaced);
// Legalisation is a big change so force a slack redistribution here
if (ctx->slack_redist_iter > 0 && cfg.budgetBased)
assign_budget(ctx, true /* quiet */);
}
require_legal = false;
} else if (cfg.budgetBased && ctx->slack_redist_iter > 0 && iter % ctx->slack_redist_iter == 0) {
assign_budget(ctx, true /* quiet */);
}
// Invoke timing analysis to obtain criticalities
if (!cfg.budgetBased)
get_criticalities(ctx, &net_crit);
// Need to rebuild costs after criticalities change
setup_costs();
// Recalculate total metric entirely to avoid rounding errors
// accumulating over time
curr_wirelen_cost = total_wirelen_cost();
curr_timing_cost = total_timing_cost();
last_wirelen_cost = curr_wirelen_cost;
last_timing_cost = curr_timing_cost;
// Let the UI show visualization updates.
ctx->yield();
}
auto saplace_end = std::chrono::high_resolution_clock::now();
log_info("SA placement time %.02fs\n", std::chrono::duration<float>(saplace_end - saplace_start).count());
// Final post-pacement validitiy check
ctx->yield();
for (auto bel : ctx->getBels()) {
CellInfo *cell = ctx->getBoundBelCell(bel);
if (!ctx->isBelLocationValid(bel)) {
std::string cell_text = "no cell";
if (cell != nullptr)
cell_text = std::string("cell '") + ctx->nameOf(cell) + "'";
if (ctx->force) {
log_warning("post-placement validity check failed for Bel '%s' "
"(%s)\n",
ctx->getBelName(bel).c_str(ctx), cell_text.c_str());
} else {
log_error("post-placement validity check failed for Bel '%s' "
"(%s)\n",
ctx->getBelName(bel).c_str(ctx), cell_text.c_str());
}
}
}
for (auto cell : sorted(ctx->cells))
if (get_constraints_distance(ctx, cell.second) != 0)
log_error("constraint satisfaction check failed for cell '%s' at Bel '%s'\n", cell.first.c_str(ctx),
ctx->getBelName(cell.second->bel).c_str(ctx));
timing_analysis(ctx);
ctx->unlock();
return true;
}
private:
// Initial random placement
void place_initial(CellInfo *cell)
{
bool all_placed = false;
int iters = 25;
while (!all_placed) {
BelId best_bel = BelId();
uint64_t best_score = std::numeric_limits<uint64_t>::max(),
best_ripup_score = std::numeric_limits<uint64_t>::max();
CellInfo *ripup_target = nullptr;
BelId ripup_bel = BelId();
if (cell->bel != BelId()) {
ctx->unbindBel(cell->bel);
}
IdString targetType = cell->type;
for (auto bel : ctx->getBels()) {
if (ctx->getBelType(bel) == targetType && ctx->isValidBelForCell(cell, bel)) {
if (ctx->checkBelAvail(bel)) {
uint64_t score = ctx->rng64();
if (score <= best_score) {
best_score = score;
best_bel = bel;
}
} else {
uint64_t score = ctx->rng64();
CellInfo *bound_cell = ctx->getBoundBelCell(bel);
if (score <= best_ripup_score && bound_cell->belStrength < STRENGTH_STRONG) {
best_ripup_score = score;
ripup_target = bound_cell;
ripup_bel = bel;
}
}
}
}
if (best_bel == BelId()) {
if (iters == 0 || ripup_bel == BelId())
log_error("failed to place cell '%s' of type '%s'\n", cell->name.c_str(ctx), cell->type.c_str(ctx));
--iters;
ctx->unbindBel(ripup_target->bel);
best_bel = ripup_bel;
} else {
all_placed = true;
}
ctx->bindBel(best_bel, cell, STRENGTH_WEAK);
// Back annotate location
cell->attrs[ctx->id("BEL")] = ctx->getBelName(cell->bel).str(ctx);
cell = ripup_target;
}
}
// Attempt a SA position swap, return true on success or false on failure
bool try_swap_position(CellInfo *cell, BelId newBel)
{
moveChange.reset();
BelId oldBel = cell->bel;
CellInfo *other_cell = ctx->getBoundBelCell(newBel);
if (other_cell != nullptr && other_cell->belStrength > STRENGTH_WEAK) {
return false;
}
int old_dist = get_constraints_distance(ctx, cell);
int new_dist;
if (other_cell != nullptr)
old_dist += get_constraints_distance(ctx, other_cell);
double delta = 0;
ctx->unbindBel(oldBel);
if (other_cell != nullptr) {
ctx->unbindBel(newBel);
}
ctx->bindBel(newBel, cell, STRENGTH_WEAK);
if (other_cell != nullptr) {
ctx->bindBel(oldBel, other_cell, STRENGTH_WEAK);
}
add_move_cell(moveChange, cell, oldBel);
if (other_cell != nullptr) {
add_move_cell(moveChange, other_cell, newBel);
}
if (!ctx->isBelLocationValid(newBel) || ((other_cell != nullptr && !ctx->isBelLocationValid(oldBel)))) {
ctx->unbindBel(newBel);
if (other_cell != nullptr)
ctx->unbindBel(oldBel);
goto swap_fail;
}
// Recalculate metrics for all nets touched by the peturbation
compute_cost_changes(moveChange);
new_dist = get_constraints_distance(ctx, cell);
if (other_cell != nullptr)
new_dist += get_constraints_distance(ctx, other_cell);
delta = lambda * (moveChange.timing_delta / last_timing_cost) +
(1 - lambda) * (double(moveChange.wirelen_delta) / last_wirelen_cost);
delta += (cfg.constraintWeight / temp) * (new_dist - old_dist) / last_wirelen_cost;
n_move++;
// SA acceptance criterea
if (delta < 0 || (temp > 1e-8 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) {
n_accept++;
} else {
if (other_cell != nullptr)
ctx->unbindBel(oldBel);
ctx->unbindBel(newBel);
goto swap_fail;
}
commit_cost_changes(moveChange);
return true;
swap_fail:
ctx->bindBel(oldBel, cell, STRENGTH_WEAK);
if (other_cell != nullptr) {
ctx->bindBel(newBel, other_cell, STRENGTH_WEAK);
}
return false;
}
inline bool is_constrained(CellInfo *cell) {
return cell->constr_parent != nullptr || !cell->constr_children.empty();
}
// Swap the Bel of a cell with another, return the original location
BelId swap_cell_bels(CellInfo *cell, BelId newBel) {
BelId oldBel = cell->bel;
CellInfo *bound = ctx->getBoundBelCell(newBel);
if (bound != nullptr)
ctx->unbindBel(newBel);
ctx->unbindBel(oldBel);
ctx->bindBel(newBel, cell, is_constrained(cell) ? STRENGTH_STRONG : STRENGTH_WEAK);
if (bound != nullptr)
ctx->bindBel(oldBel, bound, is_constrained(bound) ? STRENGTH_STRONG : STRENGTH_WEAK);
return oldBel;
}
// Discover the relative positions of all cells in a chain
void discover_chain(Loc baseLoc, CellInfo *cell, std::vector<std::pair<CellInfo*, Loc>> &cell_rel) {
Loc cellLoc = ctx->getBelLocation(cell->bel);
Loc rel{cellLoc.x - baseLoc.x, cellLoc.y - baseLoc.y, cellLoc.z};
cell_rel.emplace_back(std::make_pair(cell, rel));
for (auto child : cell->constr_children)
discover_chain(baseLoc, child, cell_rel);
}
// Attempt to swap a chain with a non-chain
bool try_swap_chain(CellInfo *cell, BelId newBase) {
std::vector<std::pair<CellInfo *, Loc>> cell_rel;
std::unordered_set<IdString> cells;
std::vector<std::pair<CellInfo*, BelId>> moves_made;
std::vector<std::pair<CellInfo *, BelId>> dest_bels;
double delta = 0;
moveChange.reset();
if (ctx->debug)
log_info("finding cells for chain swap %s\n", cell->name.c_str(ctx));
Loc baseLoc = ctx->getBelLocation(cell->bel);
discover_chain(baseLoc, cell, cell_rel);
Loc newBaseLoc = ctx->getBelLocation(newBase);
NPNR_ASSERT(newBaseLoc.z == baseLoc.z);
for (const auto &cr : cell_rel)
cells.insert(cr.first->name);
for (const auto &cr : cell_rel) {
Loc targetLoc = {newBaseLoc.x + cr.second.x, newBaseLoc.y + cr.second.y, cr.second.z};
BelId targetBel = ctx->getBelByLocation(targetLoc);
if (targetBel == BelId())
return false;
if (ctx->getBelType(targetBel) != cell->type)
return false;
CellInfo *bound = ctx->getBoundBelCell(targetBel);
// We don't consider swapping chains with other chains, at least for the time being - unless it is
// part of this chain
if (bound != nullptr && !cells.count(bound->name) && (bound->belStrength >= STRENGTH_STRONG || is_constrained(bound)))
return false;
dest_bels.emplace_back(std::make_pair(cr.first, targetBel));
}
if (ctx->debug)
log_info("trying chain swap %s\n", cell->name.c_str(ctx));
// <cell, oldBel>
for (const auto &db : dest_bels) {
BelId oldBel = swap_cell_bels(db.first, db.second);
moves_made.emplace_back(std::make_pair(db.first, oldBel));
}
for (const auto &mm : moves_made) {
if (!ctx->isBelLocationValid(mm.first->bel))
goto swap_fail;
if (!ctx->isBelLocationValid(mm.second))
goto swap_fail;
add_move_cell(moveChange, mm.first, mm.second);
CellInfo *bound = ctx->getBoundBelCell(mm.second);
if (bound != nullptr)
add_move_cell(moveChange, bound, mm.first->bel);
}
compute_cost_changes(moveChange);
delta = lambda * (moveChange.timing_delta / last_timing_cost) +
(1 - lambda) * (double(moveChange.wirelen_delta) / last_wirelen_cost);
n_move++;
// SA acceptance criterea
if (delta < 0 || (temp > 1e-8 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) {
n_accept++;
if (ctx->debug)
log_info("accepted chain swap %s\n", cell->name.c_str(ctx));
} else {
goto swap_fail;
}
commit_cost_changes(moveChange);
return true;
swap_fail:
for (const auto &entry : boost::adaptors::reverse(moves_made))
swap_cell_bels(entry.first, entry.second);
return false;
}
// Find a random Bel of the correct type for a cell, within the specified
// diameter
BelId random_bel_for_cell(CellInfo *cell, int force_z = -1)
{
IdString targetType = cell->type;
Loc curr_loc = ctx->getBelLocation(cell->bel);
while (true) {
int nx = ctx->rng(2 * diameter + 1) + std::max(curr_loc.x - diameter, 0);
int ny = ctx->rng(2 * diameter + 1) + std::max(curr_loc.y - diameter, 0);
int beltype_idx, beltype_cnt;
std::tie(beltype_idx, beltype_cnt) = bel_types.at(targetType);
if (beltype_cnt < cfg.minBelsForGridPick)
nx = ny = 0;
if (nx >= int(fast_bels.at(beltype_idx).size()))
continue;
if (ny >= int(fast_bels.at(beltype_idx).at(nx).size()))
continue;
const auto &fb = fast_bels.at(beltype_idx).at(nx).at(ny);
if (fb.size() == 0)
continue;
BelId bel = fb.at(ctx->rng(int(fb.size())));
if (force_z != -1) {
Loc loc = ctx->getBelLocation(bel);
if (loc.z != force_z)
continue;
}
if (locked_bels.find(bel) != locked_bels.end())
continue;
return bel;
}
}
// Return true if a net is to be entirely ignored
inline bool ignore_net(NetInfo *net)
{
return net->driver.cell == nullptr || net->driver.cell->bel == BelId() ||
ctx->getBelGlobalBuf(net->driver.cell->bel);
}
// Get the bounding box for a net
inline BoundingBox get_net_bounds(NetInfo *net)
{
BoundingBox bb;
NPNR_ASSERT(net->driver.cell != nullptr);
Loc dloc = ctx->getBelLocation(net->driver.cell->bel);
bb.x0 = dloc.x;
bb.x1 = dloc.x;
bb.y0 = dloc.y;
bb.y1 = dloc.y;
for (auto user : net->users) {
if (user.cell->bel == BelId())
continue;
Loc uloc = ctx->getBelLocation(user.cell->bel);
bb.x0 = std::min(bb.x0, uloc.x);
bb.x1 = std::max(bb.x1, uloc.x);
bb.y0 = std::min(bb.y0, uloc.y);
bb.y1 = std::max(bb.y1, uloc.y);
}
return bb;
}
// Get the timing cost for an arc of a net
inline double get_timing_cost(NetInfo *net, size_t user)
{
int cc;
if (net->driver.cell == nullptr)
return 0;
if (ctx->getPortTimingClass(net->driver.cell, net->driver.port, cc) == TMG_IGNORE)
return 0;
if (cfg.budgetBased) {
double delay = ctx->getDelayNS(ctx->predictDelay(net, net->users.at(user)));
return std::min(10.0, std::exp(delay - ctx->getDelayNS(net->users.at(user).budget)));
} else {
auto crit = net_crit.find(net->name);
if (crit == net_crit.end() || crit->second.criticality.empty())
return 0;
double delay = ctx->getDelayNS(ctx->predictDelay(net, net->users.at(user)));
return delay * std::pow(crit->second.criticality.at(user), crit_exp);
}
}
// Set up the cost maps
void setup_costs()
{
for (auto net : sorted(ctx->nets)) {
NetInfo *ni = net.second;
if (ignore_net(ni))
continue;
net_bounds[ni->name] = get_net_bounds(ni);
net_arc_tcost[ni->name].resize(ni->users.size());
for (size_t i = 0; i < ni->users.size(); i++)
net_arc_tcost[ni->name][i] = get_timing_cost(ni, i);
}
}
// Get the total wiring cost for the design
wirelen_t total_wirelen_cost()
{
wirelen_t cost = 0;
for (const auto &net : net_bounds)
cost += net.second.hpwl();
return cost;
}
// Get the total timing cost for the design
double total_timing_cost()
{
double cost = 0;
for (const auto &net : net_arc_tcost) {
for (auto arc_cost : net.second) {
cost += arc_cost;
}
}
return cost;
}
// Cost-change-related data for a move
struct MoveChangeData
{
std::unordered_set<IdString> bounds_changed_nets;
std::unordered_set<std::pair<IdString, size_t>> changed_arcs;
std::unordered_map<IdString, BoundingBox> new_net_bounds;
std::unordered_map<std::pair<IdString, size_t>, double> new_arc_costs;
wirelen_t wirelen_delta = 0;
double timing_delta = 0;
void reset()
{
bounds_changed_nets.clear();
changed_arcs.clear();
new_net_bounds.clear();
new_arc_costs.clear();
wirelen_delta = 0;
timing_delta = 0;
}
} moveChange;
void add_move_cell(MoveChangeData &mc, CellInfo *cell, BelId old_bel)
{
Loc curr_loc = ctx->getBelLocation(cell->bel);
Loc old_loc = ctx->getBelLocation(old_bel);
// Check net bounds
for (const auto &port : cell->ports) {
NetInfo *pn = port.second.net;
if (pn == nullptr)
continue;
if (ignore_net(pn))
continue;
const BoundingBox &curr_bounds = net_bounds[pn->name];
// If the old location was at the edge of the bounds, or the new location exceeds the bounds,
// an update is needed
if (curr_bounds.touches_bounds(old_loc.x, old_loc.y) || !curr_bounds.is_inside_inc(curr_loc.x, curr_loc.y))
mc.bounds_changed_nets.insert(pn->name);
// Output ports - all arcs change timing
if (port.second.type == PORT_OUT) {
int cc;
TimingPortClass cls = ctx->getPortTimingClass(cell, port.first, cc);
if (cls != TMG_IGNORE)
for (size_t i = 0; i < pn->users.size(); i++)
mc.changed_arcs.insert(std::make_pair(pn->name, i));
} else if (port.second.type == PORT_IN) {
mc.changed_arcs.insert(std::make_pair(pn->name, fast_port_to_user.at(&port.second)));
}
}
}
void compute_cost_changes(MoveChangeData &md)
{
for (const auto &bc : md.bounds_changed_nets) {
wirelen_t old_hpwl = net_bounds.at(bc).hpwl();
auto bounds = get_net_bounds(ctx->nets.at(bc).get());
md.new_net_bounds[bc] = bounds;
md.wirelen_delta += (bounds.hpwl() - old_hpwl);
}
for (const auto &tc : md.changed_arcs) {
double old_cost = net_arc_tcost.at(tc.first).at(tc.second);
double new_cost = get_timing_cost(ctx->nets.at(tc.first).get(), tc.second);
md.new_arc_costs[tc] = new_cost;
md.timing_delta += (new_cost - old_cost);
}
}
void commit_cost_changes(MoveChangeData &md)
{
for (const auto &bc : md.new_net_bounds)
net_bounds[bc.first] = bc.second;
for (const auto &tc : md.new_arc_costs)
net_arc_tcost[tc.first.first].at(tc.first.second) = tc.second;
curr_wirelen_cost += md.wirelen_delta;
curr_timing_cost += md.timing_delta;
}
// Build the cell port -> user index
void build_port_index()
{
for (auto net : sorted(ctx->nets)) {
NetInfo *ni = net.second;
for (size_t i = 0; i < ni->users.size(); i++) {
auto &usr = ni->users.at(i);
fast_port_to_user[&(usr.cell->ports.at(usr.port))] = i;
}
}
}
// Get the combined wirelen/timing metric
inline double curr_metric() { return lambda * curr_timing_cost + (1 - lambda) * curr_wirelen_cost; }
// Map nets to their bounding box (so we can skip recompute for moves that do not exceed the bounds
std::unordered_map<IdString, BoundingBox> net_bounds;
// Map net arcs to their timing cost (criticality * delay ns)
std::unordered_map<IdString, std::vector<double>> net_arc_tcost;
// Fast lookup for cell port to net user index
std::unordered_map<const PortInfo *, size_t> fast_port_to_user;
// Wirelength and timing cost at last and current iteration
wirelen_t last_wirelen_cost, curr_wirelen_cost;
double last_timing_cost, curr_timing_cost;
// Criticality data from timing analysis
NetCriticalityMap net_crit;
Context *ctx;
float temp = 10;
float crit_exp = 8;
float lambda = 0.5;
bool improved = false;
int n_move, n_accept;
int diameter = 35, max_x = 1, max_y = 1;
std::unordered_map<IdString, std::tuple<int, int>> bel_types;
std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels;
std::unordered_set<BelId> locked_bels;
bool require_legal = true;
const float legalise_temp = 0.00015;
const float post_legalise_temp = 0.0003;
const float post_legalise_dia_scale = 1.5;
Placer1Cfg cfg;
};
Placer1Cfg::Placer1Cfg(Context *ctx) : Settings(ctx)
{
constraintWeight = get<float>("placer1/constraintWeight", 10);
minBelsForGridPick = get<int>("placer1/minBelsForGridPick", 64);
budgetBased = get<bool>("placer1/budgetBased", false);
}
bool placer1(Context *ctx, Placer1Cfg cfg)
{
try {
SAPlacer placer(ctx, cfg);
placer.place();
log_info("Checksum: 0x%08x\n", ctx->checksum());
#ifndef NDEBUG
ctx->lock();
ctx->check();
ctx->unlock();
#endif
return true;
} catch (log_execution_error_exception) {
#ifndef NDEBUG
ctx->check();
#endif
return false;
}
}
NEXTPNR_NAMESPACE_END
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