976 lines
38 KiB
C++
976 lines
38 KiB
C++
/*
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* nextpnr -- Next Generation Place and Route
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*
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* Copyright (C) 2018 Clifford Wolf <clifford@symbioticeda.com>
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* Copyright (C) 2018 David Shah <david@symbioticeda.com>
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*
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* Simulated annealing implementation based on arachne-pnr
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* Copyright (C) 2015-2018 Cotton Seed
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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*/
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#include "placer1.h"
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#include <algorithm>
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#include <boost/lexical_cast.hpp>
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#include <boost/range/adaptor/reversed.hpp>
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#include <chrono>
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#include <cmath>
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#include <iostream>
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#include <limits>
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#include <list>
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#include <map>
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#include <ostream>
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#include <queue>
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#include <set>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <vector>
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#include "log.h"
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#include "place_common.h"
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#include "timing.h"
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#include "util.h"
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namespace std {
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template <> struct hash<std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, std::size_t>>
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{
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std::size_t operator()(const std::pair<NEXTPNR_NAMESPACE_PREFIX IdString, std::size_t> &idp) const noexcept
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{
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std::size_t seed = 0;
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boost::hash_combine(seed, hash<NEXTPNR_NAMESPACE_PREFIX IdString>()(idp.first));
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boost::hash_combine(seed, hash<std::size_t>()(idp.second));
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return seed;
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}
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};
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} // namespace std
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NEXTPNR_NAMESPACE_BEGIN
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class SAPlacer
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{
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private:
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struct BoundingBox
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{
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int x0 = 0, x1 = 0, y0 = 0, y1 = 0;
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bool is_inside_inc(int x, int y) const { return x >= x0 && x <= x1 && y >= y0 && y <= y1; }
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bool touches_bounds(int x, int y) const { return x == x0 || x == x1 || y == y0 || y == y1; }
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wirelen_t hpwl() const { return wirelen_t((x1 - x0) + (y1 - y0)); }
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};
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public:
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SAPlacer(Context *ctx, Placer1Cfg cfg) : ctx(ctx), cfg(cfg)
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{
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int num_bel_types = 0;
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for (auto bel : ctx->getBels()) {
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IdString type = ctx->getBelType(bel);
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if (bel_types.find(type) == bel_types.end()) {
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bel_types[type] = std::tuple<int, int>(num_bel_types++, 1);
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} else {
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std::get<1>(bel_types.at(type))++;
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}
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}
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for (auto bel : ctx->getBels()) {
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Loc loc = ctx->getBelLocation(bel);
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IdString type = ctx->getBelType(bel);
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int type_idx = std::get<0>(bel_types.at(type));
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int type_cnt = std::get<1>(bel_types.at(type));
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if (type_cnt < cfg.minBelsForGridPick)
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loc.x = loc.y = 0;
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if (int(fast_bels.size()) < type_idx + 1)
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fast_bels.resize(type_idx + 1);
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if (int(fast_bels.at(type_idx).size()) < (loc.x + 1))
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fast_bels.at(type_idx).resize(loc.x + 1);
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if (int(fast_bels.at(type_idx).at(loc.x).size()) < (loc.y + 1))
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fast_bels.at(type_idx).at(loc.x).resize(loc.y + 1);
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max_x = std::max(max_x, loc.x);
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max_y = std::max(max_y, loc.y);
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fast_bels.at(type_idx).at(loc.x).at(loc.y).push_back(bel);
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}
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diameter = std::max(max_x, max_y) + 1;
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net_bounds.resize(ctx->nets.size());
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net_arc_tcost.resize(ctx->nets.size());
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moveChange.already_bounds_changed.resize(ctx->nets.size());
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moveChange.already_changed_arcs.resize(ctx->nets.size());
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old_udata.reserve(ctx->nets.size());
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net_by_udata.reserve(ctx->nets.size());
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decltype(NetInfo::udata) n = 0;
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for (auto &net : ctx->nets) {
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old_udata.emplace_back(net.second->udata);
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net_arc_tcost.at(n).resize(net.second->users.size());
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moveChange.already_changed_arcs.at(n).resize(net.second->users.size());
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net.second->udata = n++;
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net_by_udata.push_back(net.second.get());
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}
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for (auto ®ion : sorted(ctx->region)) {
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Region *r = region.second;
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BoundingBox bb;
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if (r->constr_bels) {
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bb.x0 = std::numeric_limits<int>::max();
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bb.x1 = std::numeric_limits<int>::min();
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bb.y0 = std::numeric_limits<int>::max();
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bb.y1 = std::numeric_limits<int>::min();
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for (auto bel : r->bels) {
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Loc loc = ctx->getBelLocation(bel);
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bb.x0 = std::min(bb.x0, loc.x);
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bb.x1 = std::max(bb.x1, loc.x);
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bb.y0 = std::min(bb.y0, loc.y);
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bb.y1 = std::max(bb.y1, loc.y);
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}
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} else {
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bb.x0 = 0;
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bb.y0 = 0;
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bb.x1 = max_x;
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bb.y1 = max_y;
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}
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region_bounds[r->name] = bb;
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}
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build_port_index();
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}
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~SAPlacer()
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{
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for (auto &net : ctx->nets)
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net.second->udata = old_udata[net.second->udata];
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}
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bool place(bool refine = false)
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{
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log_break();
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ctx->lock();
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size_t placed_cells = 0;
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std::vector<CellInfo *> autoplaced;
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std::vector<CellInfo *> chain_basis;
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if (!refine) {
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// Initial constraints placer
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for (auto &cell_entry : ctx->cells) {
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CellInfo *cell = cell_entry.second.get();
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auto loc = cell->attrs.find(ctx->id("BEL"));
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if (loc != cell->attrs.end()) {
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std::string loc_name = loc->second;
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BelId bel = ctx->getBelByName(ctx->id(loc_name));
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if (bel == BelId()) {
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log_error("No Bel named \'%s\' located for "
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"this chip (processing BEL attribute on \'%s\')\n",
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loc_name.c_str(), cell->name.c_str(ctx));
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}
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IdString bel_type = ctx->getBelType(bel);
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if (bel_type != cell->type) {
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log_error("Bel \'%s\' of type \'%s\' does not match cell "
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"\'%s\' of type \'%s\'\n",
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loc_name.c_str(), bel_type.c_str(ctx), cell->name.c_str(ctx), cell->type.c_str(ctx));
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}
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if (!ctx->isValidBelForCell(cell, bel)) {
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log_error("Bel \'%s\' of type \'%s\' is not valid for cell "
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"\'%s\' of type \'%s\'\n",
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loc_name.c_str(), bel_type.c_str(ctx), cell->name.c_str(ctx), cell->type.c_str(ctx));
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}
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auto bound_cell = ctx->getBoundBelCell(bel);
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if (bound_cell) {
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log_error(
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"Cell \'%s\' cannot be bound to bel \'%s\' since it is already bound to cell \'%s\'\n",
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cell->name.c_str(ctx), loc_name.c_str(), bound_cell->name.c_str(ctx));
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}
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ctx->bindBel(bel, cell, STRENGTH_USER);
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locked_bels.insert(bel);
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placed_cells++;
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}
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}
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int constr_placed_cells = placed_cells;
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log_info("Placed %d cells based on constraints.\n", int(placed_cells));
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ctx->yield();
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// Sort to-place cells for deterministic initial placement
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for (auto &cell : ctx->cells) {
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CellInfo *ci = cell.second.get();
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if (ci->bel == BelId()) {
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autoplaced.push_back(cell.second.get());
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}
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}
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std::sort(autoplaced.begin(), autoplaced.end(), [](CellInfo *a, CellInfo *b) { return a->name < b->name; });
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ctx->shuffle(autoplaced);
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auto iplace_start = std::chrono::high_resolution_clock::now();
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// Place cells randomly initially
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log_info("Creating initial placement for remaining %d cells.\n", int(autoplaced.size()));
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for (auto cell : autoplaced) {
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place_initial(cell);
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placed_cells++;
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if ((placed_cells - constr_placed_cells) % 500 == 0)
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log_info(" initial placement placed %d/%d cells\n", int(placed_cells - constr_placed_cells),
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int(autoplaced.size()));
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}
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if ((placed_cells - constr_placed_cells) % 500 != 0)
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log_info(" initial placement placed %d/%d cells\n", int(placed_cells - constr_placed_cells),
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int(autoplaced.size()));
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if (cfg.budgetBased && ctx->slack_redist_iter > 0)
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assign_budget(ctx);
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ctx->yield();
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auto iplace_end = std::chrono::high_resolution_clock::now();
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log_info("Initial placement time %.02fs\n",
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std::chrono::duration<float>(iplace_end - iplace_start).count());
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log_info("Running simulated annealing placer.\n");
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} else {
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for (auto &cell : ctx->cells) {
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CellInfo *ci = cell.second.get();
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if (ci->belStrength > STRENGTH_STRONG)
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continue;
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else if (ci->constr_parent != nullptr)
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continue;
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else if (!ci->constr_children.empty() || ci->constr_z != ci->UNCONSTR)
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chain_basis.push_back(ci);
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else
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autoplaced.push_back(ci);
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}
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require_legal = false;
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diameter = 3;
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}
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auto saplace_start = std::chrono::high_resolution_clock::now();
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// Invoke timing analysis to obtain criticalities
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if (!cfg.budgetBased)
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get_criticalities(ctx, &net_crit);
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// Calculate costs after initial placement
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setup_costs();
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curr_wirelen_cost = total_wirelen_cost();
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curr_timing_cost = total_timing_cost();
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last_wirelen_cost = curr_wirelen_cost;
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last_timing_cost = curr_timing_cost;
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wirelen_t avg_wirelen = curr_wirelen_cost;
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wirelen_t min_wirelen = curr_wirelen_cost;
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int n_no_progress = 0;
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temp = refine ? 1e-7 : cfg.startTemp;
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// Main simulated annealing loop
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for (int iter = 1;; iter++) {
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n_move = n_accept = 0;
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improved = false;
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if (iter % 5 == 0 || iter == 1)
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log_info(" at iteration #%d: temp = %f, timing cost = "
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"%.0f, wirelen = %.0f\n",
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iter, temp, double(curr_timing_cost), double(curr_wirelen_cost));
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for (int m = 0; m < 15; ++m) {
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// Loop through all automatically placed cells
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for (auto cell : autoplaced) {
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// Find another random Bel for this cell
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BelId try_bel = random_bel_for_cell(cell);
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// If valid, try and swap to a new position and see if
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// the new position is valid/worthwhile
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if (try_bel != BelId() && try_bel != cell->bel)
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try_swap_position(cell, try_bel);
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}
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// Also try swapping chains, if applicable
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for (auto cb : chain_basis) {
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Loc chain_base_loc = ctx->getBelLocation(cb->bel);
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BelId try_base = random_bel_for_cell(cb, chain_base_loc.z);
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if (try_base != BelId() && try_base != cb->bel)
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try_swap_chain(cb, try_base);
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}
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}
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if (curr_wirelen_cost < min_wirelen) {
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min_wirelen = curr_wirelen_cost;
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improved = true;
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}
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// Heuristic to improve placement on the 8k
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if (improved)
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n_no_progress = 0;
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else
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n_no_progress++;
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if (temp <= 1e-7 && n_no_progress >= (refine ? 1 : 5)) {
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log_info(" at iteration #%d: temp = %f, timing cost = "
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"%.0f, wirelen = %.0f \n",
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iter, temp, double(curr_timing_cost), double(curr_wirelen_cost));
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break;
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}
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double Raccept = double(n_accept) / double(n_move);
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int M = std::max(max_x, max_y) + 1;
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if (ctx->verbose)
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log("iter #%d: temp = %f, timing cost = "
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"%.0f, wirelen = %.0f, dia = %d, Ra = %.02f \n",
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iter, temp, double(curr_timing_cost), double(curr_wirelen_cost), diameter, Raccept);
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if (curr_wirelen_cost < 0.95 * avg_wirelen && curr_wirelen_cost > 0) {
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avg_wirelen = 0.8 * avg_wirelen + 0.2 * curr_wirelen_cost;
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} else {
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double diam_next = diameter * (1.0 - 0.44 + Raccept);
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diameter = std::max<int>(1, std::min<int>(M, int(diam_next + 0.5)));
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if (Raccept > 0.96) {
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temp *= 0.5;
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} else if (Raccept > 0.8) {
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temp *= 0.9;
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} else if (Raccept > 0.15 && diameter > 1) {
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temp *= 0.95;
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} else {
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temp *= 0.8;
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}
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}
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// Once cooled below legalise threshold, run legalisation and start requiring
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// legal moves only
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if (diameter < legalise_dia && require_legal) {
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if (legalise_relative_constraints(ctx)) {
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// Only increase temperature if something was moved
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autoplaced.clear();
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chain_basis.clear();
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for (auto cell : sorted(ctx->cells)) {
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if (cell.second->belStrength <= STRENGTH_STRONG && cell.second->constr_parent == nullptr &&
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!cell.second->constr_children.empty())
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chain_basis.push_back(cell.second);
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else if (cell.second->belStrength < STRENGTH_STRONG)
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autoplaced.push_back(cell.second);
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}
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// temp = post_legalise_temp;
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// diameter = std::min<int>(M, diameter * post_legalise_dia_scale);
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ctx->shuffle(autoplaced);
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// Legalisation is a big change so force a slack redistribution here
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if (ctx->slack_redist_iter > 0 && cfg.budgetBased)
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assign_budget(ctx, true /* quiet */);
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}
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require_legal = false;
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} else if (cfg.budgetBased && ctx->slack_redist_iter > 0 && iter % ctx->slack_redist_iter == 0) {
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assign_budget(ctx, true /* quiet */);
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}
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// Invoke timing analysis to obtain criticalities
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if (!cfg.budgetBased)
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get_criticalities(ctx, &net_crit);
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// Need to rebuild costs after criticalities change
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setup_costs();
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// Recalculate total metric entirely to avoid rounding errors
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// accumulating over time
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curr_wirelen_cost = total_wirelen_cost();
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curr_timing_cost = total_timing_cost();
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last_wirelen_cost = curr_wirelen_cost;
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last_timing_cost = curr_timing_cost;
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// Let the UI show visualization updates.
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ctx->yield();
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}
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auto saplace_end = std::chrono::high_resolution_clock::now();
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log_info("SA placement time %.02fs\n", std::chrono::duration<float>(saplace_end - saplace_start).count());
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// Final post-pacement validitiy check
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ctx->yield();
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for (auto bel : ctx->getBels()) {
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CellInfo *cell = ctx->getBoundBelCell(bel);
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if (!ctx->isBelLocationValid(bel)) {
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std::string cell_text = "no cell";
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if (cell != nullptr)
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cell_text = std::string("cell '") + ctx->nameOf(cell) + "'";
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if (ctx->force) {
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log_warning("post-placement validity check failed for Bel '%s' "
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"(%s)\n",
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ctx->getBelName(bel).c_str(ctx), cell_text.c_str());
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} else {
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log_error("post-placement validity check failed for Bel '%s' "
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"(%s)\n",
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ctx->getBelName(bel).c_str(ctx), cell_text.c_str());
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}
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}
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}
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for (auto cell : sorted(ctx->cells))
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if (get_constraints_distance(ctx, cell.second) != 0)
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log_error("constraint satisfaction check failed for cell '%s' at Bel '%s'\n", cell.first.c_str(ctx),
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ctx->getBelName(cell.second->bel).c_str(ctx));
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timing_analysis(ctx);
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ctx->unlock();
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return true;
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}
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private:
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// Initial random placement
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void place_initial(CellInfo *cell)
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{
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bool all_placed = false;
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int iters = 25;
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while (!all_placed) {
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BelId best_bel = BelId();
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uint64_t best_score = std::numeric_limits<uint64_t>::max(),
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best_ripup_score = std::numeric_limits<uint64_t>::max();
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CellInfo *ripup_target = nullptr;
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BelId ripup_bel = BelId();
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if (cell->bel != BelId()) {
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ctx->unbindBel(cell->bel);
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}
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IdString targetType = cell->type;
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auto proc_bel = [&](BelId bel) {
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if (ctx->getBelType(bel) == targetType && ctx->isValidBelForCell(cell, bel)) {
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if (ctx->checkBelAvail(bel)) {
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uint64_t score = ctx->rng64();
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if (score <= best_score) {
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best_score = score;
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best_bel = bel;
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}
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} else {
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uint64_t score = ctx->rng64();
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CellInfo *bound_cell = ctx->getBoundBelCell(bel);
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if (score <= best_ripup_score && bound_cell->belStrength < STRENGTH_STRONG) {
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best_ripup_score = score;
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ripup_target = bound_cell;
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ripup_bel = bel;
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}
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}
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}
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};
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if (cell->region != nullptr && cell->region->constr_bels) {
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for (auto bel : cell->region->bels) {
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proc_bel(bel);
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}
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|
} else {
|
|
for (auto bel : ctx->getBels()) {
|
|
proc_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)
|
|
{
|
|
static const double epsilon = 1e-20;
|
|
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 / std::max<double>(last_timing_cost, epsilon)) +
|
|
(1 - lambda) * (double(moveChange.wirelen_delta) / std::max<double>(last_wirelen_cost, epsilon));
|
|
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) || !check_cell_bel_region(mm.first, mm.first->bel))
|
|
goto swap_fail;
|
|
if (!ctx->isBelLocationValid(mm.second))
|
|
goto swap_fail;
|
|
CellInfo *bound = ctx->getBoundBelCell(mm.second);
|
|
if (bound && !check_cell_bel_region(bound, bound->bel))
|
|
goto swap_fail;
|
|
add_move_cell(moveChange, mm.first, 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-9 && (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);
|
|
int count = 0;
|
|
|
|
int dx = diameter, dy = diameter;
|
|
if (cell->region != nullptr && cell->region->constr_bels) {
|
|
dx = std::min(diameter, (region_bounds[cell->region->name].x1 - region_bounds[cell->region->name].x0) + 1);
|
|
dy = std::min(diameter, (region_bounds[cell->region->name].y1 - region_bounds[cell->region->name].y0) + 1);
|
|
// Clamp location to within bounds
|
|
curr_loc.x = std::max(region_bounds[cell->region->name].x0, curr_loc.x);
|
|
curr_loc.x = std::min(region_bounds[cell->region->name].x1, curr_loc.x);
|
|
curr_loc.y = std::max(region_bounds[cell->region->name].y0, curr_loc.y);
|
|
curr_loc.y = std::min(region_bounds[cell->region->name].y1, curr_loc.y);
|
|
}
|
|
|
|
while (true) {
|
|
int nx = ctx->rng(2 * dx + 1) + std::max(curr_loc.x - dx, 0);
|
|
int ny = ctx->rng(2 * dy + 1) + std::max(curr_loc.y - dy, 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 (!check_cell_bel_region(cell, bel))
|
|
continue;
|
|
if (locked_bels.find(bel) != locked_bels.end())
|
|
continue;
|
|
count++;
|
|
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->udata] = get_net_bounds(ni);
|
|
if (ctx->timing_driven && int(ni->users.size()) < cfg.timingFanoutThresh)
|
|
for (size_t i = 0; i < ni->users.size(); i++)
|
|
net_arc_tcost[ni->udata][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.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) {
|
|
cost += arc_cost;
|
|
}
|
|
}
|
|
return cost;
|
|
}
|
|
|
|
// Cost-change-related data for a move
|
|
struct MoveChangeData
|
|
{
|
|
std::vector<decltype(NetInfo::udata)> bounds_changed_nets;
|
|
std::vector<std::pair<decltype(NetInfo::udata), size_t>> changed_arcs;
|
|
|
|
std::vector<bool> already_bounds_changed;
|
|
std::vector<std::vector<bool>> already_changed_arcs;
|
|
|
|
std::vector<std::pair<decltype(NetInfo::udata), BoundingBox>> new_net_bounds;
|
|
std::vector<std::pair<std::pair<decltype(NetInfo::udata), size_t>, double>> new_arc_costs;
|
|
|
|
wirelen_t wirelen_delta = 0;
|
|
double timing_delta = 0;
|
|
|
|
void reset()
|
|
{
|
|
for (auto bc : bounds_changed_nets)
|
|
already_bounds_changed[bc] = false;
|
|
for (const auto &tc : changed_arcs)
|
|
already_changed_arcs[tc.first][tc.second] = false;
|
|
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->udata];
|
|
// 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))
|
|
if (!mc.already_bounds_changed[pn->udata]) {
|
|
mc.bounds_changed_nets.push_back(pn->udata);
|
|
mc.already_bounds_changed[pn->udata] = true;
|
|
}
|
|
if (ctx->timing_driven && int(pn->users.size()) < cfg.timingFanoutThresh) {
|
|
// 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++)
|
|
if (!mc.already_changed_arcs[pn->udata][i]) {
|
|
mc.changed_arcs.emplace_back(std::make_pair(pn->udata, i));
|
|
mc.already_changed_arcs[pn->udata][i] = true;
|
|
}
|
|
} else if (port.second.type == PORT_IN) {
|
|
auto usr = fast_port_to_user.at(&port.second);
|
|
if (!mc.already_changed_arcs[pn->udata][usr]) {
|
|
mc.changed_arcs.emplace_back(std::make_pair(pn->udata, usr));
|
|
mc.already_changed_arcs[pn->udata][usr] = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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(net_by_udata.at(bc));
|
|
md.new_net_bounds.emplace_back(std::make_pair(bc, bounds));
|
|
md.wirelen_delta += (bounds.hpwl() - old_hpwl);
|
|
md.already_bounds_changed[bc] = false;
|
|
}
|
|
if (ctx->timing_driven) {
|
|
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(net_by_udata.at(tc.first), tc.second);
|
|
md.new_arc_costs.emplace_back(std::make_pair(tc, new_cost));
|
|
md.timing_delta += (new_cost - old_cost);
|
|
md.already_changed_arcs[tc.first][tc.second] = false;
|
|
}
|
|
}
|
|
}
|
|
|
|
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::vector<BoundingBox> net_bounds;
|
|
// Map net arcs to their timing cost (criticality * delay ns)
|
|
std::vector<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::unordered_map<IdString, BoundingBox> region_bounds;
|
|
std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels;
|
|
std::unordered_set<BelId> locked_bels;
|
|
std::vector<NetInfo *> net_by_udata;
|
|
std::vector<decltype(NetInfo::udata)> old_udata;
|
|
bool require_legal = true;
|
|
const int legalise_dia = 4;
|
|
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);
|
|
startTemp = get<float>("placer1/startTemp", 1);
|
|
timingFanoutThresh = std::numeric_limits<int>::max();
|
|
}
|
|
|
|
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;
|
|
}
|
|
}
|
|
|
|
bool placer1_refine(Context *ctx, Placer1Cfg cfg)
|
|
{
|
|
try {
|
|
SAPlacer placer(ctx, cfg);
|
|
placer.place(true);
|
|
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
|