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Diffstat (limited to 'common/placer_heap.cc')
| -rw-r--r-- | common/placer_heap.cc | 1545 |
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diff --git a/common/placer_heap.cc b/common/placer_heap.cc new file mode 100644 index 00000000..f9b639f8 --- /dev/null +++ b/common/placer_heap.cc @@ -0,0 +1,1545 @@ +/* + * nextpnr -- Next Generation Place and Route + * + * Copyright (C) 2019 David Shah <david@symbioticeda.com> + * + * 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. + * + * [[cite]] HeAP + * Analytical Placement for Heterogeneous FPGAs, Marcel Gort and Jason H. Anderson + * https://janders.eecg.utoronto.ca/pdfs/marcelfpl12.pdf + * + * [[cite]] SimPL + * SimPL: An Effective Placement Algorithm, Myung-Chul Kim, Dong-Jin Lee and Igor L. Markov + * http://www.ece.umich.edu/cse/awards/pdfs/iccad10-simpl.pdf + * + * Notable changes from the original algorithm + * - Following the other nextpnr placer, Bels are placed rather than CLBs. This means a strict legalisation pass is + * added in addition to coarse legalisation (referred to as "spreading" to avoid confusion with strict legalisation) + * as described in HeAP to ensure validity. This searches random bels in the vicinity of the position chosen by + * spreading, with diameter increasing over iterations, with a heuristic to prefer lower wirelength choices. + * - To make the placer timing-driven, the bound2bound weights are multiplied by (1 + 10 * crit^2) + */ + +#ifdef WITH_HEAP + +#include "placer_heap.h" +#include <Eigen/Core> +#include <Eigen/IterativeLinearSolvers> +#include <boost/optional.hpp> +#include <chrono> +#include <deque> +#include <fstream> +#include <numeric> +#include <queue> +#include <thread> +#include <tuple> +#include <unordered_map> +#include "log.h" +#include "nextpnr.h" +#include "place_common.h" +#include "placer1.h" +#include "timing.h" +#include "util.h" +NEXTPNR_NAMESPACE_BEGIN + +namespace { +// A simple internal representation for a sparse system of equations Ax = rhs +// This is designed to decouple the functions that build the matrix to the engine that +// solves it, and the representation that requires +template <typename T> struct EquationSystem +{ + + EquationSystem(size_t rows, size_t cols) + { + A.resize(cols); + rhs.resize(rows); + } + + // Simple sparse format, easy to convert to CCS for solver + std::vector<std::vector<std::pair<int, T>>> A; // col -> (row, x[row, col]) sorted by row + std::vector<T> rhs; // RHS vector + void reset() + { + for (auto &col : A) + col.clear(); + std::fill(rhs.begin(), rhs.end(), T()); + } + + void add_coeff(int row, int col, T val) + { + auto &Ac = A.at(col); + // Binary search + int b = 0, e = int(Ac.size()) - 1; + while (b <= e) { + int i = (b + e) / 2; + if (Ac.at(i).first == row) { + Ac.at(i).second += val; + return; + } + if (Ac.at(i).first > row) + e = i - 1; + else + b = i + 1; + } + Ac.insert(Ac.begin() + b, std::make_pair(row, val)); + } + + void add_rhs(int row, T val) { rhs[row] += val; } + + void solve(std::vector<T> &x) + { + using namespace Eigen; + if (x.empty()) + return; + NPNR_ASSERT(x.size() == A.size()); + + VectorXd vx(x.size()), vb(rhs.size()); + SparseMatrix<T> mat(A.size(), A.size()); + + std::vector<int> colnnz; + for (auto &Ac : A) + colnnz.push_back(int(Ac.size())); + mat.reserve(colnnz); + for (int col = 0; col < int(A.size()); col++) { + auto &Ac = A.at(col); + for (auto &el : Ac) + mat.insert(el.first, col) = el.second; + } + + for (int i = 0; i < int(x.size()); i++) + vx[i] = x.at(i); + for (int i = 0; i < int(rhs.size()); i++) + vb[i] = rhs.at(i); + + ConjugateGradient<SparseMatrix<T>, Lower | Upper> solver; + solver.setTolerance(1e-5); + VectorXd xr = solver.compute(mat).solveWithGuess(vb, vx); + for (int i = 0; i < int(x.size()); i++) + x.at(i) = xr[i]; + // for (int i = 0; i < int(x.size()); i++) + // log_info("x[%d] = %f\n", i, x.at(i)); + } +}; + +} // namespace + +class HeAPPlacer +{ + public: + HeAPPlacer(Context *ctx, PlacerHeapCfg cfg) : ctx(ctx), cfg(cfg) { Eigen::initParallel(); } + + bool place() + { + auto startt = std::chrono::high_resolution_clock::now(); + + ctx->lock(); + place_constraints(); + build_fast_bels(); + seed_placement(); + update_all_chains(); + wirelen_t hpwl = total_hpwl(); + log_info("Creating initial analytic placement for %d cells, random placement wirelen = %d.\n", + int(place_cells.size()), int(hpwl)); + for (int i = 0; i < 4; i++) { + setup_solve_cells(); + auto solve_startt = std::chrono::high_resolution_clock::now(); + std::thread xaxis([&]() { build_solve_direction(false, -1); }); + build_solve_direction(true, -1); + xaxis.join(); + auto solve_endt = std::chrono::high_resolution_clock::now(); + solve_time += std::chrono::duration<double>(solve_endt - solve_startt).count(); + + update_all_chains(); + + hpwl = total_hpwl(); + log_info(" at initial placer iter %d, wirelen = %d\n", i, int(hpwl)); + } + + wirelen_t solved_hpwl = 0, spread_hpwl = 0, legal_hpwl = 0, best_hpwl = std::numeric_limits<wirelen_t>::max(); + int iter = 0, stalled = 0; + + std::vector<std::tuple<CellInfo *, BelId, PlaceStrength>> solution; + + std::vector<std::unordered_set<IdString>> heap_runs; + std::unordered_set<IdString> all_celltypes; + std::unordered_map<IdString, int> ct_count; + + for (auto cell : place_cells) { + if (!all_celltypes.count(cell->type)) { + heap_runs.push_back(std::unordered_set<IdString>{cell->type}); + all_celltypes.insert(cell->type); + } + ct_count[cell->type]++; + } + // If more than 98% of cells are one cell type, always solve all at once + // Otherwise, follow full HeAP strategy of rotate&all + for (auto &c : ct_count) + if (c.second >= 0.98 * int(place_cells.size())) { + heap_runs.clear(); + break; + } + + heap_runs.push_back(all_celltypes); + // The main HeAP placer loop + log_info("Running main analytical placer.\n"); + while (stalled < 5 && (solved_hpwl <= legal_hpwl * 0.8)) { + // Alternate between particular Bel types and all bels + for (auto &run : heap_runs) { + auto run_startt = std::chrono::high_resolution_clock::now(); + + setup_solve_cells(&run); + if (solve_cells.empty()) + continue; + // Heuristic: don't bother with threading below a certain size + auto solve_startt = std::chrono::high_resolution_clock::now(); + + if (solve_cells.size() < 500) { + build_solve_direction(false, (iter == 0) ? -1 : iter); + build_solve_direction(true, (iter == 0) ? -1 : iter); + } else { + std::thread xaxis([&]() { build_solve_direction(false, (iter == 0) ? -1 : iter); }); + build_solve_direction(true, (iter == 0) ? -1 : iter); + xaxis.join(); + } + auto solve_endt = std::chrono::high_resolution_clock::now(); + solve_time += std::chrono::duration<double>(solve_endt - solve_startt).count(); + update_all_chains(); + solved_hpwl = total_hpwl(); + + update_all_chains(); + for (auto type : sorted(run)) + CutSpreader(this, type).run(); + + update_all_chains(); + spread_hpwl = total_hpwl(); + legalise_placement_strict(true); + update_all_chains(); + + legal_hpwl = total_hpwl(); + auto run_stopt = std::chrono::high_resolution_clock::now(); + log_info(" at iteration #%d, type %s: wirelen solved = %d, spread = %d, legal = %d; time = %.02fs\n", + iter + 1, (run.size() > 1 ? "ALL" : run.begin()->c_str(ctx)), int(solved_hpwl), + int(spread_hpwl), int(legal_hpwl), + std::chrono::duration<double>(run_stopt - run_startt).count()); + } + + if (ctx->timing_driven) + get_criticalities(ctx, &net_crit); + + if (legal_hpwl < best_hpwl) { + best_hpwl = legal_hpwl; + stalled = 0; + // Save solution + solution.clear(); + for (auto cell : sorted(ctx->cells)) { + solution.emplace_back(cell.second, cell.second->bel, cell.second->belStrength); + } + } else { + ++stalled; + } + for (auto &cl : cell_locs) { + cl.second.legal_x = cl.second.x; + cl.second.legal_y = cl.second.y; + } + ctx->yield(); + ++iter; + } + + // Apply saved solution + for (auto &sc : solution) { + CellInfo *cell = std::get<0>(sc); + if (cell->bel != BelId()) + ctx->unbindBel(cell->bel); + } + for (auto &sc : solution) { + CellInfo *cell; + BelId bel; + PlaceStrength strength; + std::tie(cell, bel, strength) = sc; + ctx->bindBel(bel, cell, strength); + } + + for (auto cell : sorted(ctx->cells)) { + if (cell.second->bel == BelId()) + log_error("Found unbound cell %s\n", cell.first.c_str(ctx)); + if (ctx->getBoundBelCell(cell.second->bel) != cell.second) + log_error("Found cell %s with mismatched binding\n", cell.first.c_str(ctx)); + if (ctx->debug) + log_info("AP soln: %s -> %s\n", cell.first.c_str(ctx), ctx->getBelName(cell.second->bel).c_str(ctx)); + } + + ctx->unlock(); + auto endtt = std::chrono::high_resolution_clock::now(); + log_info("HeAP Placer Time: %.02fs\n", std::chrono::duration<double>(endtt - startt).count()); + log_info(" of which solving equations: %.02fs\n", solve_time); + log_info(" of which spreading cells: %.02fs\n", cl_time); + log_info(" of which strict legalisation: %.02fs\n", sl_time); + + ctx->check(); + + placer1_refine(ctx, Placer1Cfg(ctx)); + + return true; + } + + private: + Context *ctx; + PlacerHeapCfg cfg; + + int max_x = 0, max_y = 0; + std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels; + std::unordered_map<IdString, std::tuple<int, int>> bel_types; + + // For fast handling of heterogeneosity during initial placement without full legalisation, + // for each Bel type this goes from x or y to the nearest x or y where a Bel of a given type exists + // This is particularly important for the iCE40 architecture, where multipliers and BRAM only exist at the + // edges and corners respectively + std::vector<std::vector<int>> nearest_row_with_bel; + std::vector<std::vector<int>> nearest_col_with_bel; + + // In some cases, we can't use bindBel because we allow overlap in the earlier stages. So we use this custom + // structure instead + struct CellLocation + { + int x, y; + int legal_x, legal_y; + double rawx, rawy; + bool locked, global; + }; + std::unordered_map<IdString, CellLocation> cell_locs; + // The set of cells that we will actually place. This excludes locked cells and children cells of macros/chains + // (only the root of each macro is placed.) + std::vector<CellInfo *> place_cells; + + // The cells in the current equation being solved (a subset of place_cells in some cases, where we only place + // cells of a certain type) + std::vector<CellInfo *> solve_cells; + + // For cells in a chain, this is the ultimate root cell of the chain (sometimes this is not constr_parent + // where chains are within chains + std::unordered_map<IdString, CellInfo *> chain_root; + std::unordered_map<IdString, int> chain_size; + + // The offset from chain_root to a cell in the chain + std::unordered_map<IdString, std::pair<int, int>> cell_offsets; + + // Performance counting + double solve_time = 0, cl_time = 0, sl_time = 0; + + NetCriticalityMap net_crit; + + // Place cells with the BEL attribute set to constrain them + void place_constraints() + { + 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); + placed_cells++; + } + } + log_info("Placed %d cells based on constraints.\n", int(placed_cells)); + ctx->yield(); + } + + // Construct the fast_bels, nearest_row_with_bel and nearest_col_with_bel + void build_fast_bels() + { + + 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()) { + if (!ctx->checkBelAvail(bel)) + continue; + Loc loc = ctx->getBelLocation(bel); + IdString type = ctx->getBelType(bel); + int type_idx = std::get<0>(bel_types.at(type)); + 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); + } + + nearest_row_with_bel.resize(num_bel_types, std::vector<int>(max_y + 1, -1)); + nearest_col_with_bel.resize(num_bel_types, std::vector<int>(max_x + 1, -1)); + for (auto bel : ctx->getBels()) { + if (!ctx->checkBelAvail(bel)) + continue; + Loc loc = ctx->getBelLocation(bel); + int type_idx = std::get<0>(bel_types.at(ctx->getBelType(bel))); + auto &nr = nearest_row_with_bel.at(type_idx), &nc = nearest_col_with_bel.at(type_idx); + // Traverse outwards through nearest_row_with_bel and nearest_col_with_bel, stopping once + // another row/col is already recorded as being nearer + for (int x = loc.x; x <= max_x; x++) { + if (nc.at(x) != -1 && std::abs(loc.x - nc.at(x)) <= (x - loc.x)) + break; + nc.at(x) = loc.x; + } + for (int x = loc.x - 1; x >= 0; x--) { + if (nc.at(x) != -1 && std::abs(loc.x - nc.at(x)) <= (loc.x - x)) + break; + nc.at(x) = loc.x; + } + for (int y = loc.y; y <= max_y; y++) { + if (nr.at(y) != -1 && std::abs(loc.y - nr.at(y)) <= (y - loc.y)) + break; + nr.at(y) = loc.y; + } + for (int y = loc.y - 1; y >= 0; y--) { + if (nr.at(y) != -1 && std::abs(loc.y - nr.at(y)) <= (loc.y - y)) + break; + nr.at(y) = loc.y; + } + } + } + + // Build and solve in one direction + void build_solve_direction(bool yaxis, int iter) + { + for (int i = 0; i < 5; i++) { + EquationSystem<double> esx(solve_cells.size(), solve_cells.size()); + build_equations(esx, yaxis, iter); + solve_equations(esx, yaxis); + } + } + + // Check if a cell has any meaningful connectivity + bool has_connectivity(CellInfo *cell) + { + for (auto port : cell->ports) { + if (port.second.net != nullptr && port.second.net->driver.cell != nullptr && + !port.second.net->users.empty()) + return true; + } + return false; + } + + // Build up a random initial placement, without regard to legality + // FIXME: Are there better approaches to the initial placement (e.g. greedy?) + void seed_placement() + { + std::unordered_map<IdString, std::deque<BelId>> available_bels; + for (auto bel : ctx->getBels()) { + if (!ctx->checkBelAvail(bel)) + continue; + available_bels[ctx->getBelType(bel)].push_back(bel); + } + for (auto &t : available_bels) { + std::random_shuffle(t.second.begin(), t.second.end(), [&](size_t n) { return ctx->rng(int(n)); }); + } + for (auto cell : sorted(ctx->cells)) { + CellInfo *ci = cell.second; + if (ci->bel != BelId()) { + Loc loc = ctx->getBelLocation(ci->bel); + cell_locs[cell.first].x = loc.x; + cell_locs[cell.first].y = loc.y; + cell_locs[cell.first].locked = true; + cell_locs[cell.first].global = ctx->getBelGlobalBuf(ci->bel); + } else if (ci->constr_parent == nullptr) { + bool placed = false; + while (!placed) { + if (!available_bels.count(ci->type) || available_bels.at(ci->type).empty()) + log_error("Unable to place cell '%s', no Bels remaining of type '%s'\n", ci->name.c_str(ctx), + ci->type.c_str(ctx)); + BelId bel = available_bels.at(ci->type).back(); + available_bels.at(ci->type).pop_back(); + Loc loc = ctx->getBelLocation(bel); + cell_locs[cell.first].x = loc.x; + cell_locs[cell.first].y = loc.y; + cell_locs[cell.first].locked = false; + cell_locs[cell.first].global = ctx->getBelGlobalBuf(bel); + // FIXME + if (has_connectivity(cell.second) && !cfg.ioBufTypes.count(ci->type)) { + place_cells.push_back(ci); + placed = true; + } else { + if (ctx->isValidBelForCell(ci, bel)) { + ctx->bindBel(bel, ci, STRENGTH_STRONG); + cell_locs[cell.first].locked = true; + placed = true; + } else { + available_bels.at(ci->type).push_front(bel); + } + } + } + } + } + } + + // Setup the cells to be solved, returns the number of rows + int setup_solve_cells(std::unordered_set<IdString> *celltypes = nullptr) + { + int row = 0; + solve_cells.clear(); + // First clear the udata of all cells + for (auto cell : sorted(ctx->cells)) + cell.second->udata = dont_solve; + // Then update cells to be placed, which excludes cell children + for (auto cell : place_cells) { + if (celltypes && !celltypes->count(cell->type)) + continue; + cell->udata = row++; + solve_cells.push_back(cell); + } + // Finally, update the udata of children + for (auto chained : chain_root) + ctx->cells.at(chained.first)->udata = chained.second->udata; + return row; + } + + // Update the location of all children of a chain + void update_chain(CellInfo *cell, CellInfo *root) + { + const auto &base = cell_locs[cell->name]; + for (auto child : cell->constr_children) { + chain_size[root->name]++; + if (child->constr_x != child->UNCONSTR) + cell_locs[child->name].x = std::min(max_x, base.x + child->constr_x); + else + cell_locs[child->name].x = base.x; // better handling of UNCONSTR? + if (child->constr_y != child->UNCONSTR) + cell_locs[child->name].y = std::min(max_y, base.y + child->constr_y); + else + cell_locs[child->name].y = base.y; // better handling of UNCONSTR? + chain_root[child->name] = root; + if (!child->constr_children.empty()) + update_chain(child, root); + } + } + + // Update all chains + void update_all_chains() + { + for (auto cell : place_cells) { + chain_size[cell->name] = 1; + if (!cell->constr_children.empty()) + update_chain(cell, cell); + } + } + + // Run a function on all ports of a net - including the driver and all users + template <typename Tf> void foreach_port(NetInfo *net, Tf func) + { + if (net->driver.cell != nullptr) + func(net->driver, -1); + for (size_t i = 0; i < net->users.size(); i++) + func(net->users.at(i), i); + } + + // Build the system of equations for either X or Y + void build_equations(EquationSystem<double> &es, bool yaxis, int iter = -1) + { + // Return the x or y position of a cell, depending on ydir + auto cell_pos = [&](CellInfo *cell) { return yaxis ? cell_locs.at(cell->name).y : cell_locs.at(cell->name).x; }; + auto legal_pos = [&](CellInfo *cell) { + return yaxis ? cell_locs.at(cell->name).legal_y : cell_locs.at(cell->name).legal_x; + }; + + es.reset(); + + for (auto net : sorted(ctx->nets)) { + NetInfo *ni = net.second; + if (ni->driver.cell == nullptr) + continue; + if (ni->users.empty()) + continue; + if (cell_locs.at(ni->driver.cell->name).global) + continue; + // Find the bounds of the net in this axis, and the ports that correspond to these bounds + PortRef *lbport = nullptr, *ubport = nullptr; + int lbpos = std::numeric_limits<int>::max(), ubpos = std::numeric_limits<int>::min(); + foreach_port(ni, [&](PortRef &port, int user_idx) { + int pos = cell_pos(port.cell); + if (pos < lbpos) { + lbpos = pos; + lbport = &port; + } + if (pos > ubpos) { + ubpos = pos; + ubport = &port; + } + }); + NPNR_ASSERT(lbport != nullptr); + NPNR_ASSERT(ubport != nullptr); + + auto stamp_equation = [&](PortRef &var, PortRef &eqn, double weight) { + if (eqn.cell->udata == dont_solve) + return; + int row = eqn.cell->udata; + int v_pos = cell_pos(var.cell); + if (var.cell->udata != dont_solve) { + es.add_coeff(row, var.cell->udata, weight); + } else { + es.add_rhs(row, -v_pos * weight); + } + if (cell_offsets.count(var.cell->name)) { + es.add_rhs(row, -(yaxis ? cell_offsets.at(var.cell->name).second + : cell_offsets.at(var.cell->name).first) * + weight); + } + }; + + // Add all relevant connections to the matrix + foreach_port(ni, [&](PortRef &port, int user_idx) { + int this_pos = cell_pos(port.cell); + auto process_arc = [&](PortRef *other) { + if (other == &port) + return; + int o_pos = cell_pos(other->cell); + double weight = 1.0 / (ni->users.size() * std::max<double>(1, std::abs(o_pos - this_pos))); + + if (user_idx != -1 && net_crit.count(ni->name)) { + auto &nc = net_crit.at(ni->name); + if (user_idx < int(nc.criticality.size())) + weight *= (1.0 + cfg.timingWeight * + std::pow(nc.criticality.at(user_idx), cfg.criticalityExponent)); + } + + // If cell 0 is not fixed, it will stamp +w on its equation and -w on the other end's equation, + // if the other end isn't fixed + stamp_equation(port, port, weight); + stamp_equation(port, *other, -weight); + stamp_equation(*other, *other, weight); + stamp_equation(*other, port, -weight); + }; + process_arc(lbport); + process_arc(ubport); + }); + } + if (iter != -1) { + float alpha = cfg.alpha; + for (size_t row = 0; row < solve_cells.size(); row++) { + int l_pos = legal_pos(solve_cells.at(row)); + int c_pos = cell_pos(solve_cells.at(row)); + + double weight = alpha * iter / std::max<double>(1, std::abs(l_pos - c_pos)); + // Add an arc from legalised to current position + es.add_coeff(row, row, weight); + es.add_rhs(row, weight * l_pos); + } + } + } + + // Build the system of equations for either X or Y + void solve_equations(EquationSystem<double> &es, bool yaxis) + { + // Return the x or y position of a cell, depending on ydir + auto cell_pos = [&](CellInfo *cell) { return yaxis ? cell_locs.at(cell->name).y : cell_locs.at(cell->name).x; }; + std::vector<double> vals; + std::transform(solve_cells.begin(), solve_cells.end(), std::back_inserter(vals), cell_pos); + es.solve(vals); + for (size_t i = 0; i < vals.size(); i++) + if (yaxis) { + cell_locs.at(solve_cells.at(i)->name).rawy = vals.at(i); + cell_locs.at(solve_cells.at(i)->name).y = std::min(max_y, std::max(0, int(vals.at(i)))); + } else { + cell_locs.at(solve_cells.at(i)->name).rawx = vals.at(i); + cell_locs.at(solve_cells.at(i)->name).x = std::min(max_x, std::max(0, int(vals.at(i)))); + } + } + + // Compute HPWL + wirelen_t total_hpwl() + { + wirelen_t hpwl = 0; + for (auto net : sorted(ctx->nets)) { + NetInfo *ni = net.second; + if (ni->driver.cell == nullptr) + continue; + CellLocation &drvloc = cell_locs.at(ni->driver.cell->name); + if (drvloc.global) + continue; + int xmin = drvloc.x, xmax = drvloc.x, ymin = drvloc.y, ymax = drvloc.y; + for (auto &user : ni->users) { + CellLocation &usrloc = cell_locs.at(user.cell->name); + xmin = std::min(xmin, usrloc.x); + xmax = std::max(xmax, usrloc.x); + ymin = std::min(ymin, usrloc.y); + ymax = std::max(ymax, usrloc.y); + } + hpwl += (xmax - xmin) + (ymax - ymin); + } + return hpwl; + } + + // Strict placement legalisation, performed after the initial HeAP spreading + void legalise_placement_strict(bool require_validity = false) + { + auto startt = std::chrono::high_resolution_clock::now(); + + // Unbind all cells placed in this solution + for (auto cell : sorted(ctx->cells)) { + CellInfo *ci = cell.second; + if (ci->bel != BelId() && (ci->udata != dont_solve || + (chain_root.count(ci->name) && chain_root.at(ci->name)->udata != dont_solve))) + ctx->unbindBel(ci->bel); + } + + // At the moment we don't follow the full HeAP algorithm using cuts for legalisation, instead using + // the simple greedy largest-macro-first approach. + std::priority_queue<std::pair<int, IdString>> remaining; + for (auto cell : solve_cells) { + remaining.emplace(chain_size[cell->name], cell->name); + } + int ripup_radius = 2; + int total_iters = 0; + while (!remaining.empty()) { + auto top = remaining.top(); + remaining.pop(); + + CellInfo *ci = ctx->cells.at(top.second).get(); + // Was now placed, ignore + if (ci->bel != BelId()) + continue; + // log_info(" Legalising %s (%s)\n", top.second.c_str(ctx), ci->type.c_str(ctx)); + int bt = std::get<0>(bel_types.at(ci->type)); + auto &fb = fast_bels.at(bt); + int radius = 0; + int iter = 0; + int iter_at_radius = 0; + bool placed = false; + BelId bestBel; + int best_inp_len = std::numeric_limits<int>::max(); + + total_iters++; + if (total_iters > int(solve_cells.size())) { + total_iters = 0; + ripup_radius = std::max(std::max(max_x, max_y), ripup_radius * 2); + } + + while (!placed) { + + int nx = ctx->rng(2 * radius + 1) + std::max(cell_locs.at(ci->name).x - radius, 0); + int ny = ctx->rng(2 * radius + 1) + std::max(cell_locs.at(ci->name).y - radius, 0); + + iter++; + iter_at_radius++; + if (iter >= (10 * (radius + 1))) { + radius = std::min(std::max(max_x, max_y), radius + 1); + while (radius < std::max(max_x, max_y)) { + for (int x = std::max(0, cell_locs.at(ci->name).x - radius); + x <= std::min(max_x, cell_locs.at(ci->name).x + radius); x++) { + if (x >= int(fb.size())) + break; + for (int y = std::max(0, cell_locs.at(ci->name).y - radius); + y <= std::min(max_y, cell_locs.at(ci->name).y + radius); y++) { + if (y >= int(fb.at(x).size())) + break; + if (fb.at(x).at(y).size() > 0) + goto notempty; + } + } + radius = std::min(std::max(max_x, max_y), radius + 1); + } + notempty: + iter_at_radius = 0; + iter = 0; + } + if (nx < 0 || nx > max_x) + continue; + if (ny < 0 || ny > max_y) + continue; + + // ny = nearest_row_with_bel.at(bt).at(ny); + // nx = nearest_col_with_bel.at(bt).at(nx); + + if (nx >= int(fb.size())) + continue; + if (ny >= int(fb.at(nx).size())) + continue; + if (fb.at(nx).at(ny).empty()) + continue; + + int need_to_explore = 2 * radius; + + if (iter_at_radius >= need_to_explore && bestBel != BelId()) { + CellInfo *bound = ctx->getBoundBelCell(bestBel); + if (bound != nullptr) { + ctx->unbindBel(bound->bel); + remaining.emplace(chain_size[bound->name], bound->name); + } + ctx->bindBel(bestBel, ci, STRENGTH_WEAK); + placed = true; + Loc loc = ctx->getBelLocation(bestBel); + cell_locs[ci->name].x = loc.x; + cell_locs[ci->name].y = loc.y; + break; + } + + if (ci->constr_children.empty() && !ci->constr_abs_z) { + for (auto sz : fb.at(nx).at(ny)) { + if (ctx->checkBelAvail(sz) || (radius > ripup_radius || ctx->rng(20000) < 10)) { + CellInfo *bound = ctx->getBoundBelCell(sz); + if (bound != nullptr) { + if (bound->constr_parent != nullptr || !bound->constr_children.empty() || + bound->constr_abs_z) + continue; + ctx->unbindBel(bound->bel); + } + ctx->bindBel(sz, ci, STRENGTH_WEAK); + if (require_validity && !ctx->isBelLocationValid(sz)) { + ctx->unbindBel(sz); + if (bound != nullptr) + ctx->bindBel(sz, bound, STRENGTH_WEAK); + } else if (iter_at_radius < need_to_explore) { + ctx->unbindBel(sz); + if (bound != nullptr) + ctx->bindBel(sz, bound, STRENGTH_WEAK); + int input_len = 0; + for (auto &port : ci->ports) { + auto &p = port.second; + if (p.type != PORT_IN || p.net == nullptr || p.net->driver.cell == nullptr) + continue; + CellInfo *drv = p.net->driver.cell; + auto drv_loc = cell_locs.find(drv->name); + if (drv_loc == cell_locs.end()) + continue; + if (drv_loc->second.global) + continue; + input_len += std::abs(drv_loc->second.x - nx) + std::abs(drv_loc->second.y - ny); + } + if (input_len < best_inp_len) { + best_inp_len = input_len; + bestBel = sz; + } + break; + } else { + if (bound != nullptr) + remaining.emplace(chain_size[bound->name], bound->name); + Loc loc = ctx->getBelLocation(sz); + cell_locs[ci->name].x = loc.x; + cell_locs[ci->name].y = loc.y; + placed = true; + break; + } + } + } + } else { + for (auto sz : fb.at(nx).at(ny)) { + Loc loc = ctx->getBelLocation(sz); + if (ci->constr_abs_z && loc.z != ci->constr_z) + continue; + std::vector<std::pair<CellInfo *, BelId>> targets; + std::vector<std::pair<BelId, CellInfo *>> swaps_made; + std::queue<std::pair<CellInfo *, Loc>> visit; + visit.emplace(ci, loc); + while (!visit.empty()) { + CellInfo *vc = visit.front().first; + NPNR_ASSERT(vc->bel == BelId()); + Loc ploc = visit.front().second; + visit.pop(); + BelId target = ctx->getBelByLocation(ploc); + CellInfo *bound; + if (target == BelId() || ctx->getBelType(target) != vc->type) + goto fail; + bound = ctx->getBoundBelCell(target); + // Chains cannot overlap + if (bound != nullptr) + if (bound->constr_z != bound->UNCONSTR || bound->constr_parent != nullptr || + !bound->constr_children.empty() || bound->belStrength > STRENGTH_WEAK) + goto fail; + targets.emplace_back(vc, target); + for (auto child : vc->constr_children) { + Loc cloc = ploc; + if (child->constr_x != child->UNCONSTR) + cloc.x += child->constr_x; + if (child->constr_y != child->UNCONSTR) + cloc.y += child->constr_y; + if (child->constr_z != child->UNCONSTR) + cloc.z = child->constr_abs_z ? child->constr_z : (ploc.z + child->constr_z); + visit.emplace(child, cloc); + } + } + + for (auto &target : targets) { + CellInfo *bound = ctx->getBoundBelCell(target.second); + if (bound != nullptr) + ctx->unbindBel(target.second); + ctx->bindBel(target.second, target.first, STRENGTH_STRONG); + swaps_made.emplace_back(target.second, bound); + } + + for (auto &sm : swaps_made) { + if (!ctx->isBelLocationValid(sm.first)) + goto fail; + } + + if (false) { + fail: + for (auto &swap : swaps_made) { + ctx->unbindBel(swap.first); + if (swap.second != nullptr) + ctx->bindBel(swap.first, swap.second, STRENGTH_WEAK); + } + continue; + } + for (auto &target : targets) { + Loc loc = ctx->getBelLocation(target.second); + cell_locs[target.first->name].x = loc.x; + cell_locs[target.first->name].y = loc.y; + // log_info("%s %d %d %d\n", target.first->name.c_str(ctx), loc.x, loc.y, loc.z); + } + for (auto &swap : swaps_made) { + if (swap.second != nullptr) + remaining.emplace(chain_size[swap.second->name], swap.second->name); + } + + placed = true; + break; + } + } + } + } + auto endt = std::chrono::high_resolution_clock::now(); + sl_time += std::chrono::duration<float>(endt - startt).count(); + } + // Implementation of the cut-based spreading as described in the HeAP/SimPL papers + static constexpr float beta = 0.9; + + struct ChainExtent + { + int x0, y0, x1, y1; + }; + + struct SpreaderRegion + { + int id; + int x0, y0, x1, y1; + int cells, bels; + bool overused() const + { + if (bels < 4) + return cells > bels; + else + return cells > beta * bels; + } + }; + + class CutSpreader + { + public: + CutSpreader(HeAPPlacer *p, IdString beltype) + : p(p), ctx(p->ctx), beltype(beltype), fb(p->fast_bels.at(std::get<0>(p->bel_types.at(beltype)))) + { + } + static int seq; + void run() + { + auto startt = std::chrono::high_resolution_clock::now(); + init(); + find_overused_regions(); + for (auto &r : regions) { + if (merged_regions.count(r.id)) + continue; +#if 0 + log_info("%s (%d, %d) |_> (%d, %d) %d/%d\n", beltype.c_str(ctx), r.x0, r.y0, r.x1, r.y1, r.cells, + r.bels); +#endif + } + expand_regions(); + std::queue<std::pair<int, bool>> workqueue; +#if 0 + std::vector<std::pair<double, double>> orig; + if (ctx->debug) + for (auto c : p->solve_cells) + orig.emplace_back(p->cell_locs[c->name].rawx, p->cell_locs[c->name].rawy); +#endif + for (auto &r : regions) { + if (merged_regions.count(r.id)) + continue; +#if 0 + log_info("%s (%d, %d) |_> (%d, %d) %d/%d\n", beltype.c_str(ctx), r.x0, r.y0, r.x1, r.y1, r.cells, + r.bels); +#endif + workqueue.emplace(r.id, false); + // cut_region(r, false); + } + while (!workqueue.empty()) { + auto front = workqueue.front(); + workqueue.pop(); + auto &r = regions.at(front.first); + if (r.cells == 0) + continue; + auto res = cut_region(r, front.second); + if (res) { + workqueue.emplace(res->first, !front.second); + workqueue.emplace(res->second, !front.second); + } else { + // Try the other dir, in case stuck in one direction only + auto res2 = cut_region(r, !front.second); + if (res2) { + // log_info("RETRY SUCCESS\n"); + workqueue.emplace(res2->first, front.second); + workqueue.emplace(res2->second, front.second); + } + } + } +#if 0 + if (ctx->debug) { + std::ofstream sp("spread" + std::to_string(seq) + ".csv"); + for (size_t i = 0; i < p->solve_cells.size(); i++) { + auto &c = p->solve_cells.at(i); + if (c->type != beltype) + continue; + sp << orig.at(i).first << "," << orig.at(i).second << "," << p->cell_locs[c->name].rawx << "," << p->cell_locs[c->name].rawy << std::endl; + } + std::ofstream oc("cells" + std::to_string(seq) + ".csv"); + for (size_t y = 0; y <= p->max_y; y++) { + for (size_t x = 0; x <= p->max_x; x++) { + oc << cells_at_location.at(x).at(y).size() << ", "; + } + oc << std::endl; + } + ++seq; + } +#endif + auto endt = std::chrono::high_resolution_clock::now(); + p->cl_time += std::chrono::duration<float>(endt - startt).count(); + } + + private: + HeAPPlacer *p; + Context *ctx; + IdString beltype; + std::vector<std::vector<int>> occupancy; + std::vector<std::vector<int>> groups; + std::vector<std::vector<ChainExtent>> chaines; + std::map<IdString, ChainExtent> cell_extents; + + std::vector<std::vector<std::vector<BelId>>> &fb; + + std::vector<SpreaderRegion> regions; + std::unordered_set<int> merged_regions; + // Cells at a location, sorted by real (not integer) x and y + std::vector<std::vector<std::vector<CellInfo *>>> cells_at_location; + + int occ_at(int x, int y) { return occupancy.at(x).at(y); } + + int bels_at(int x, int y) + { + if (x >= int(fb.size()) || y >= int(fb.at(x).size())) + return 0; + return int(fb.at(x).at(y).size()); + } + + void init() + { + occupancy.resize(p->max_x + 1, std::vector<int>(p->max_y + 1, 0)); + groups.resize(p->max_x + 1, std::vector<int>(p->max_y + 1, -1)); + chaines.resize(p->max_x + 1, std::vector<ChainExtent>(p->max_y + 1)); + cells_at_location.resize(p->max_x + 1, std::vector<std::vector<CellInfo *>>(p->max_y + 1)); + for (int x = 0; x <= p->max_x; x++) + for (int y = 0; y <= p->max_y; y++) { + occupancy.at(x).at(y) = 0; + groups.at(x).at(y) = -1; + chaines.at(x).at(y) = {x, y, x, y}; + } + + auto set_chain_ext = [&](IdString cell, int x, int y) { + if (!cell_extents.count(cell)) + cell_extents[cell] = {x, y, x, y}; + else { + cell_extents[cell].x0 = std::min(cell_extents[cell].x0, x); + cell_extents[cell].y0 = std::min(cell_extents[cell].y0, y); + cell_extents[cell].x1 = std::max(cell_extents[cell].x1, x); + cell_extents[cell].y1 = std::max(cell_extents[cell].y1, y); + } + }; + + for (auto &cell : p->cell_locs) { + if (ctx->cells.at(cell.first)->type != beltype) + continue; + if (ctx->cells.at(cell.first)->belStrength > STRENGTH_STRONG) + continue; + occupancy.at(cell.second.x).at(cell.second.y)++; + // Compute ultimate extent of each chain root + if (p->chain_root.count(cell.first)) { + set_chain_ext(p->chain_root.at(cell.first)->name, cell.second.x, cell.second.y); + } else if (!ctx->cells.at(cell.first)->constr_children.empty()) { + set_chain_ext(cell.first, cell.second.x, cell.second.y); + } + } + for (auto &cell : p->cell_locs) { + if (ctx->cells.at(cell.first)->type != beltype) + continue; + // Transfer chain extents to the actual chaines structure + ChainExtent *ce = nullptr; + if (p->chain_root.count(cell.first)) + ce = &(cell_extents.at(p->chain_root.at(cell.first)->name)); + else if (!ctx->cells.at(cell.first)->constr_children.empty()) + ce = &(cell_extents.at(cell.first)); + if (ce) { + auto &lce = chaines.at(cell.second.x).at(cell.second.y); + lce.x0 = std::min(lce.x0, ce->x0); + lce.y0 = std::min(lce.y0, ce->y0); + lce.x1 = std::max(lce.x1, ce->x1); + lce.y1 = std::max(lce.y1, ce->y1); + } + } + for (auto cell : p->solve_cells) { + if (cell->type != beltype) + continue; + cells_at_location.at(p->cell_locs.at(cell->name).x).at(p->cell_locs.at(cell->name).y).push_back(cell); + } + } + void merge_regions(SpreaderRegion &merged, SpreaderRegion &mergee) + { + // Prevent grow_region from recursing while doing this + for (int x = mergee.x0; x <= mergee.x1; x++) + for (int y = mergee.y0; y <= mergee.y1; y++) { + // log_info("%d %d\n", groups.at(x).at(y), mergee.id); + NPNR_ASSERT(groups.at(x).at(y) == mergee.id); + groups.at(x).at(y) = merged.id; + merged.cells += occ_at(x, y); + merged.bels += bels_at(x, y); + } + merged_regions.insert(mergee.id); + grow_region(merged, mergee.x0, mergee.y0, mergee.x1, mergee.y1); + } + + void grow_region(SpreaderRegion &r, int x0, int y0, int x1, int y1, bool init = false) + { + // log_info("growing to (%d, %d) |_> (%d, %d)\n", x0, y0, x1, y1); + if ((x0 >= r.x0 && y0 >= r.y0 && x1 <= r.x1 && y1 <= r.y1) || init) + return; + int old_x0 = r.x0 + (init ? 1 : 0), old_y0 = r.y0, old_x1 = r.x1, old_y1 = r.y1; + r.x0 = std::min(r.x0, x0); + r.y0 = std::min(r.y0, y0); + r.x1 = std::max(r.x1, x1); + r.y1 = std::max(r.y1, y1); + + auto process_location = [&](int x, int y) { + // Merge with any overlapping regions + if (groups.at(x).at(y) == -1) { + r.bels += bels_at(x, y); + r.cells += occ_at(x, y); + } + if (groups.at(x).at(y) != -1 && groups.at(x).at(y) != r.id) + merge_regions(r, regions.at(groups.at(x).at(y))); + groups.at(x).at(y) = r.id; + // Grow to cover any chains + auto &chaine = chaines.at(x).at(y); + grow_region(r, chaine.x0, chaine.y0, chaine.x1, chaine.y1); + }; + for (int x = r.x0; x < old_x0; x++) + for (int y = r.y0; y <= r.y1; y++) + process_location(x, y); + for (int x = old_x1 + 1; x <= x1; x++) + for (int y = r.y0; y <= r.y1; y++) + process_location(x, y); + for (int y = r.y0; y < old_y0; y++) + for (int x = r.x0; x <= r.x1; x++) + process_location(x, y); + for (int y = old_y1 + 1; y <= r.y1; y++) + for (int x = r.x0; x <= r.x1; x++) + process_location(x, y); + } + + void find_overused_regions() + { + for (int x = 0; x <= p->max_x; x++) + for (int y = 0; y <= p->max_y; y++) { + // Either already in a group, or not overutilised. Ignore + if (groups.at(x).at(y) != -1 || (occ_at(x, y) <= bels_at(x, y))) + continue; + // log_info("%d %d %d\n", x, y, occ_at(x, y)); + int id = int(regions.size()); + groups.at(x).at(y) = id; + SpreaderRegion reg; + reg.id = id; + reg.x0 = reg.x1 = x; + reg.y0 = reg.y1 = y; + reg.bels = bels_at(x, y); + reg.cells = occ_at(x, y); + // Make sure we cover carries, etc + grow_region(reg, reg.x0, reg.y0, reg.x1, reg.y1, true); + + bool expanded = true; + while (expanded) { + expanded = false; + // Keep trying expansion in x and y, until we find no over-occupancy cells + // or hit grouped cells + + // First try expanding in x + if (reg.x1 < p->max_x) { + bool over_occ_x = false; + for (int y1 = reg.y0; y1 <= reg.y1; y1++) { + if (occ_at(reg.x1 + 1, y1) > bels_at(reg.x1 + 1, y1)) { + // log_info("(%d, %d) occ %d bels %d\n", reg.x1+ 1, y1, occ_at(reg.x1 + 1, y1), + // bels_at(reg.x1 + 1, y1)); + over_occ_x = true; + break; + } + } + if (over_occ_x) { + expanded = true; + grow_region(reg, reg.x0, reg.y0, reg.x1 + 1, reg.y1); + } + } + + if (reg.y1 < p->max_y) { + bool over_occ_y = false; + for (int x1 = reg.x0; x1 <= reg.x1; x1++) { + if (occ_at(x1, reg.y1 + 1) > bels_at(x1, reg.y1 + 1)) { + // log_info("(%d, %d) occ %d bels %d\n", x1, reg.y1 + 1, occ_at(x1, reg.y1 + 1), + // bels_at(x1, reg.y1 + 1)); + over_occ_y = true; + break; + } + } + if (over_occ_y) { + expanded = true; + grow_region(reg, reg.x0, reg.y0, reg.x1, reg.y1 + 1); + } + } + } + regions.push_back(reg); + } + } + + void expand_regions() + { + std::queue<int> overu_regions; + for (auto &r : regions) { + if (!merged_regions.count(r.id) && r.overused()) + overu_regions.push(r.id); + } + while (!overu_regions.empty()) { + int rid = overu_regions.front(); + overu_regions.pop(); + if (merged_regions.count(rid)) + continue; + auto ® = regions.at(rid); + while (reg.overused()) { + bool changed = false; + if (reg.x0 > 0) { + grow_region(reg, reg.x0 - 1, reg.y0, reg.x1, reg.y1); + changed = true; + if (!reg.overused()) + break; + } + if (reg.x1 < p->max_x) { + grow_region(reg, reg.x0, reg.y0, reg.x1 + 1, reg.y1); + changed = true; + if (!reg.overused()) + break; + } + if (reg.y0 > 0) { + grow_region(reg, reg.x0, reg.y0 - 1, reg.x1, reg.y1); + changed = true; + if (!reg.overused()) + break; + } + if (reg.y1 < p->max_y) { + grow_region(reg, reg.x0, reg.y0, reg.x1, reg.y1 + 1); + changed = true; + if (!reg.overused()) + break; + } + if (!changed) { + if (reg.cells > reg.bels) + log_error("Failed to expand region (%d, %d) |_> (%d, %d) of %d %ss\n", reg.x0, reg.y0, + reg.x1, reg.y1, reg.cells, beltype.c_str(ctx)); + else + break; + } + } + } + } + + // Implementation of the recursive cut-based spreading as described in the HeAP paper + // Note we use "left" to mean "-x/-y" depending on dir and "right" to mean "+x/+y" depending on dir + + std::vector<CellInfo *> cut_cells; + + boost::optional<std::pair<int, int>> cut_region(SpreaderRegion &r, bool dir) + { + cut_cells.clear(); + auto &cal = cells_at_location; + int total_cells = 0, total_bels = 0; + for (int x = r.x0; x <= r.x1; x++) { + for (int y = r.y0; y <= r.y1; y++) { + std::copy(cal.at(x).at(y).begin(), cal.at(x).at(y).end(), std::back_inserter(cut_cells)); + total_bels += bels_at(x, y); + } + } + for (auto &cell : cut_cells) { + total_cells += p->chain_size.count(cell->name) ? p->chain_size.at(cell->name) : 1; + } + std::sort(cut_cells.begin(), cut_cells.end(), [&](const CellInfo *a, const CellInfo *b) { + return dir ? (p->cell_locs.at(a->name).rawy < p->cell_locs.at(b->name).rawy) + : (p->cell_locs.at(a->name).rawx < p->cell_locs.at(b->name).rawx); + }); + + if (cut_cells.size() < 2) + return {}; + // Find the cells midpoint, counting chains in terms of their total size - making the initial source cut + int pivot_cells = 0; + int pivot = 0; + for (auto &cell : cut_cells) { + pivot_cells += p->chain_size.count(cell->name) ? p->chain_size.at(cell->name) : 1; + if (pivot_cells >= total_cells / 2) + break; + pivot++; + } + if (pivot == int(cut_cells.size())) + pivot = int(cut_cells.size()) - 1; + // log_info("orig pivot %d lc %d rc %d\n", pivot, pivot_cells, r.cells - pivot_cells); + + // Find the clearance required either side of the pivot + int clearance_l = 0, clearance_r = 0; + for (size_t i = 0; i < cut_cells.size(); i++) { + int size; + if (cell_extents.count(cut_cells.at(i)->name)) { + auto &ce = cell_extents.at(cut_cells.at(i)->name); + size = dir ? (ce.y1 - ce.y0 + 1) : (ce.x1 - ce.x0 + 1); + } else { + size = 1; + } + if (int(i) < pivot) + clearance_l = std::max(clearance_l, size); + else + clearance_r = std::max(clearance_r, size); + } + // Find the target cut that minimises difference in utilisation, whilst trying to ensure that all chains + // still fit + + // First trim the boundaries of the region in the axis-of-interest, skipping any rows/cols without any + // bels of the appropriate type + int trimmed_l = dir ? r.y0 : r.x0, trimmed_r = dir ? r.y1 : r.x1; + while (trimmed_l < (dir ? r.y1 : r.x1)) { + bool have_bels = false; + for (int i = dir ? r.x0 : r.y0; i <= (dir ? r.x1 : r.y1); i++) + if (bels_at(dir ? i : trimmed_l, dir ? trimmed_l : i) > 0) { + have_bels = true; + break; + } + if (have_bels) + break; + trimmed_l++; + } + while (trimmed_r > (dir ? r.y0 : r.x0)) { + bool have_bels = false; + for (int i = dir ? r.x0 : r.y0; i <= (dir ? r.x1 : r.y1); i++) + if (bels_at(dir ? i : trimmed_r, dir ? trimmed_r : i) > 0) { + have_bels = true; + break; + } + if (have_bels) + break; + trimmed_r--; + } + // log_info("tl %d tr %d cl %d cr %d\n", trimmed_l, trimmed_r, clearance_l, clearance_r); + if ((trimmed_r - trimmed_l + 1) <= std::max(clearance_l, clearance_r)) + return {}; + // Now find the initial target cut that minimises utilisation imbalance, whilst + // meeting the clearance requirements for any large macros + int left_cells = pivot_cells, right_cells = total_cells - pivot_cells; + int left_bels = 0, right_bels = total_bels; + int best_tgt_cut = -1; + double best_deltaU = std::numeric_limits<double>::max(); + std::pair<int, int> target_cut_bels; + for (int i = trimmed_l; i <= trimmed_r; i++) { + int slither_bels = 0; + for (int j = dir ? r.x0 : r.y0; j <= (dir ? r.x1 : r.y1); j++) { + slither_bels += dir ? bels_at(j, i) : bels_at(i, j); + } + left_bels += slither_bels; + right_bels -= slither_bels; + if (((i - trimmed_l) + 1) >= clearance_l && ((trimmed_r - i) + 1) >= clearance_r) { + // Solution is potentially valid + double aU = + std::abs(double(left_cells) / double(left_bels) - double(right_cells) / double(right_bels)); + if (aU < best_deltaU) { + best_deltaU = aU; + best_tgt_cut = i; + target_cut_bels = std::make_pair(left_bels, right_bels); + } + } + } + if (best_tgt_cut == -1) + return {}; + left_bels = target_cut_bels.first; + right_bels = target_cut_bels.second; + // log_info("pivot %d target cut %d lc %d lb %d rc %d rb %d\n", pivot, best_tgt_cut, left_cells, left_bels, + // right_cells, right_bels); + + // Peturb the source cut to eliminate overutilisation + while (pivot > 0 && (double(left_cells) / double(left_bels) > double(right_cells) / double(right_bels))) { + auto &move_cell = cut_cells.at(pivot); + int size = p->chain_size.count(move_cell->name) ? p->chain_size.at(move_cell->name) : 1; + left_cells -= size; + right_cells += size; + pivot--; + } + while (pivot < int(cut_cells.size()) - 1 && + (double(left_cells) / double(left_bels) < double(right_cells) / double(right_bels))) { + auto &move_cell = cut_cells.at(pivot + 1); + int size = p->chain_size.count(move_cell->name) ? p->chain_size.at(move_cell->name) : 1; + left_cells += size; + right_cells -= size; + pivot++; + } + // log_info("peturbed pivot %d lc %d lb %d rc %d rb %d\n", pivot, left_cells, left_bels, right_cells, + // right_bels); + // Split regions into bins, and then spread cells by linear interpolation within those bins + auto spread_binlerp = [&](int cells_start, int cells_end, double area_l, double area_r) { + int N = cells_end - cells_start; + if (N <= 2) { + for (int i = cells_start; i < cells_end; i++) { + auto &pos = dir ? p->cell_locs.at(cut_cells.at(i)->name).rawy + : p->cell_locs.at(cut_cells.at(i)->name).rawx; + pos = area_l + i * ((area_r - area_l) / N); + } + return; + } + // Split region into up to 10 (K) bins + int K = std::min<int>(N, 10); + std::vector<std::pair<int, double>> bin_bounds; // [(cell start, area start)] + bin_bounds.emplace_back(cells_start, area_l); + for (int i = 1; i < K; i++) + bin_bounds.emplace_back(cells_start + (N * i) / K, area_l + ((area_r - area_l + 0.99) * i) / K); + bin_bounds.emplace_back(cells_end, area_r + 0.99); + for (int i = 0; i < K; i++) { + auto &bl = bin_bounds.at(i), br = bin_bounds.at(i + 1); + double orig_left = dir ? p->cell_locs.at(cut_cells.at(bl.first)->name).rawy + : p->cell_locs.at(cut_cells.at(bl.first)->name).rawx; + double orig_right = dir ? p->cell_locs.at(cut_cells.at(br.first - 1)->name).rawy + : p->cell_locs.at(cut_cells.at(br.first - 1)->name).rawx; + double m = (br.second - bl.second) / std::max(0.00001, orig_right - orig_left); + for (int j = bl.first; j < br.first; j++) { + auto &pos = dir ? p->cell_locs.at(cut_cells.at(j)->name).rawy + : p->cell_locs.at(cut_cells.at(j)->name).rawx; + NPNR_ASSERT(pos >= orig_left && pos <= orig_right); + pos = bl.second + m * (pos - orig_left); + // log("[%f, %f] -> [%f, %f]: %f -> %f\n", orig_left, orig_right, bl.second, br.second, + // orig_pos, pos); + } + } + }; + spread_binlerp(0, pivot + 1, trimmed_l, best_tgt_cut); + spread_binlerp(pivot + 1, int(cut_cells.size()), best_tgt_cut + 1, trimmed_r); + // Update various data structures + for (int x = r.x0; x <= r.x1; x++) + for (int y = r.y0; y <= r.y1; y++) { + cells_at_location.at(x).at(y).clear(); + } + for (auto cell : cut_cells) { + auto &cl = p->cell_locs.at(cell->name); + cl.x = std::min(r.x1, std::max(r.x0, int(cl.rawx))); + cl.y = std::min(r.y1, std::max(r.y0, int(cl.rawy))); + cells_at_location.at(cl.x).at(cl.y).push_back(cell); + // log_info("spread pos %d %d\n", cl.x, cl.y); + } + SpreaderRegion rl, rr; + rl.id = int(regions.size()); + rl.x0 = r.x0; + rl.y0 = r.y0; + rl.x1 = dir ? r.x1 : best_tgt_cut; + rl.y1 = dir ? best_tgt_cut : r.y1; + rl.cells = left_cells; + rl.bels = left_bels; + rr.id = int(regions.size()) + 1; + rr.x0 = dir ? r.x0 : (best_tgt_cut + 1); + rr.y0 = dir ? (best_tgt_cut + 1) : r.y0; + rr.x1 = r.x1; + rr.y1 = r.y1; + rr.cells = right_cells; + rr.bels = right_bels; + regions.push_back(rl); + regions.push_back(rr); + for (int x = rl.x0; x <= rl.x1; x++) + for (int y = rl.y0; y <= rl.y1; y++) + groups.at(x).at(y) = rl.id; + for (int x = rr.x0; x <= rr.x1; x++) + for (int y = rr.y0; y <= rr.y1; y++) + groups.at(x).at(y) = rr.id; + return std::make_pair(rl.id, rr.id); + }; + }; + typedef decltype(CellInfo::udata) cell_udata_t; + cell_udata_t dont_solve = std::numeric_limits<cell_udata_t>::max(); +}; +int HeAPPlacer::CutSpreader::seq = 0; + +bool placer_heap(Context *ctx, PlacerHeapCfg cfg) { return HeAPPlacer(ctx, cfg).place(); } + +PlacerHeapCfg::PlacerHeapCfg(Context *ctx) : Settings(ctx) +{ + alpha = get<float>("placerHeap/alpha", 0.1); + criticalityExponent = get<int>("placerHeap/criticalityExponent", 2); + timingWeight = get<int>("placerHeap/timingWeight", 10); +} + +NEXTPNR_NAMESPACE_END + +#else + +#include "log.h" +#include "nextpnr.h" +#include "placer_heap.h" + +NEXTPNR_NAMESPACE_BEGIN +bool placer_heap(Context *ctx, PlacerHeapCfg cfg) +{ + log_error("nextpnr was built without the HeAP placer\n"); + return false; +} + +PlacerHeapCfg::PlacerHeapCfg(Context *ctx) : Settings(ctx) {} + +NEXTPNR_NAMESPACE_END + +#endif |