router2: fcroute-based rewrite
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Lofty
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a1ad114069
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c9b3c72bff
@ -368,12 +368,7 @@ struct Router2
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float get_togo_cost(NetInfo *net, store_index<PortRef> user, int wire, WireId src_sink, bool bwd, float crit_weight)
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{
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auto &nd = nets.at(net->udata);
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auto &wd = flat_wires[wire];
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int source_uses = 0;
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if (nd.wires.count(wd.w)) {
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source_uses = nd.wires.at(wd.w).second;
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}
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// FIXME: timing/wirelength balance?
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delay_t est_delay = ctx->estimateDelay(bwd ? src_sink : wd.w, bwd ? wd.w : src_sink);
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return ctx->getDelayNS(est_delay) * cfg.estimate_weight;
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@ -584,6 +579,259 @@ struct Router2
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(tmg.get_setup_slack(CellPortKey(net->users.at(usr_idx))) < (2 * ctx->getDelayEpsilon()));
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}
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ArcRouteResult route_arc_lofty(ThreadContext &t, NetInfo *net, store_index<PortRef> i, size_t phys_pin, bool is_mt,
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bool is_bb = true)
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{
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// Do some initial lookups and checks
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auto arc_start = std::chrono::high_resolution_clock::now();
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auto &nd = nets[net->udata];
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auto &ad = nd.arcs.at(i.idx()).at(phys_pin);
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auto &usr = net->users.at(i);
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ROUTE_LOG_DBG("Routing arc %d of net '%s' (%d, %d) -> (%d, %d)\n", i.idx(), ctx->nameOf(net), ad.bb.x0,
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ad.bb.y0, ad.bb.x1, ad.bb.y1);
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bool verbose = false; //strcmp(ctx->nameOf(net), "_zz_132__LUT4_A_Z") == 0;
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WireId src_wire = ctx->getNetinfoSourceWire(net), dst_wire = ctx->getNetinfoSinkWire(net, usr, phys_pin);
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if (src_wire == WireId())
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ARC_LOG_ERR("No wire found for port %s on source cell %s.\n", ctx->nameOf(net->driver.port),
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ctx->nameOf(net->driver.cell));
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if (dst_wire == WireId())
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ARC_LOG_ERR("No wire found for port %s on destination cell %s.\n", ctx->nameOf(usr.port),
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ctx->nameOf(usr.cell));
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int src_wire_idx = wire_to_idx.at(src_wire);
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int dst_wire_idx = wire_to_idx.at(dst_wire);
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// Calculate a timing weight based on criticality
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float crit = get_arc_crit(net, i);
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float crit_weight = (1.0f - std::pow(crit, 2));
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ROUTE_LOG_DBG(" crit=%.3f crit_weight=%.3f\n", crit, crit_weight);
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// Check if arc was already done _in this iteration_
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if (t.processed_sinks.count(dst_wire))
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return ARC_SUCCESS;
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if (verbose)
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log("awoo\n");
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// Impl note:
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// t.fwd_queue = H (i.e. the high priority nodes)
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// t.bwd_queue = G (i.e. the unexpanded nodes)
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auto low_prio = std::vector<QueuedWire>{};
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// Clear out the queues
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if (!t.fwd_queue.empty()) {
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std::priority_queue<QueuedWire, std::vector<QueuedWire>, QueuedWire::Greater> new_queue;
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t.fwd_queue.swap(new_queue);
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}
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if (!t.bwd_queue.empty()) {
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std::priority_queue<QueuedWire, std::vector<QueuedWire>, QueuedWire::Greater> new_queue;
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t.bwd_queue.swap(new_queue);
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}
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// Unvisit any previously visited wires
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reset_wires(t);
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auto wire_count = [](int x0, int x1) {
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unsigned int priority = 0;
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auto x = x1 - x0;
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// HACK: ECP5-specific.
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// H6 wires:
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priority += x / 6;
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x -= 6 * (x / 6);
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if (x % 6 == 2 || x % 6 == 4) {
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// Assume an extra H6 is used here.
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priority++;
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x -= x % 6;
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}
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// H2/H1 wires:
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priority += x / 2;
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if (x % 2 == 1) {
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// Assume an extra H2 or H1 is used here.
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priority++;
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}
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return priority;
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};
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// Fast maze search.
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auto fast_search = [&](QueuedWire curr){
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while (curr.wire != dst_wire_idx) {
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NPNR_ASSERT(curr.wire < flat_wires.size());
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auto &curr_data = flat_wires.at(curr.wire);
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// Neighbour pass 1: find priorities.
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auto lowest_priority = std::numeric_limits<unsigned int>::max();
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for (PipId dh : ctx->getPipsDownhill(curr_data.w)) {
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// Skip pips outside of box in bounding-box mode
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if (is_bb && !hit_test_pip(nd.bb, ctx->getPipLocation(dh)))
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continue;
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if (!ctx->checkPipAvailForNet(dh, net))
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continue;
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WireId next = ctx->getPipDstWire(dh);
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int next_idx = wire_to_idx.at(next);
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if (was_visited_fwd(next_idx)) {
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// Don't expand the same node twice.
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continue;
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}
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auto &nwd = flat_wires.at(next_idx);
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if (nwd.unavailable)
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continue;
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// Reserved for another net
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if (nwd.reserved_net != -1 && nwd.reserved_net != net->udata)
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continue;
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// Don't allow the same wire to be bound to the same net with a different driving pip
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auto fnd_wire = nd.wires.find(next);
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if (fnd_wire != nd.wires.end() && fnd_wire->second.first != dh)
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continue;
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if (!thread_test_wire(t, nwd))
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continue; // thread safety issue
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auto box = ctx->getRouteBoundingBox(ctx->getPipDstWire(dh), dst_wire);
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unsigned int priority = wire_count(box.x0, box.x1) + wire_count(box.y0, box.y1);
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lowest_priority = std::min(priority, lowest_priority);
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}
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// Neighbour pass 2: add high-priority nodes to the list.
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for (PipId dh : ctx->getPipsDownhill(curr_data.w)) {
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WireId next = ctx->getPipDstWire(dh);
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int next_idx = wire_to_idx.at(next);
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// Skip pips outside of box in bounding-box mode
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if (is_bb && !hit_test_pip(nd.bb, ctx->getPipLocation(dh)))
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continue;
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if (!ctx->checkPipAvailForNet(dh, net))
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continue;
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if (was_visited_fwd(next_idx))
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continue;
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auto &nwd = flat_wires.at(next_idx);
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if (nwd.unavailable)
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continue;
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// Reserved for another net
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if (nwd.reserved_net != -1 && nwd.reserved_net != net->udata)
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continue;
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// Don't allow the same wire to be bound to the same net with a different driving pip
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auto fnd_wire = nd.wires.find(next);
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if (fnd_wire != nd.wires.end() && fnd_wire->second.first != dh)
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continue;
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if (!thread_test_wire(t, nwd))
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continue; // thread safety issue
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WireScore next_score;
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next_score.criticality = crit;
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next_score.congest = curr.score.congest + score_wire_for_arc_congest(net, i, phys_pin, next, dh, crit_weight);
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next_score.delay = curr.score.delay + score_wire_for_arc_delay(net, i, phys_pin, next, dh, crit_weight);
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next_score.togo = get_togo_cost(net, i, next_idx, dst_wire, false, crit_weight);
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auto qw = QueuedWire(next_idx, next_score, t.rng.rng());
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auto box = ctx->getRouteBoundingBox(ctx->getPipDstWire(dh), dst_wire);
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unsigned int priority = wire_count(box.x0, box.x1) + wire_count(box.y0, box.y1);
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if (priority - lowest_priority == 0) {
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auto& unexplored_best = t.bwd_queue.top();
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if (t.bwd_queue.empty() || next_score.total() <= unexplored_best.score.total()) {
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t.fwd_queue.push(qw);
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} else {
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t.bwd_queue.push(qw);
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}
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} else {
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low_prio.push_back(qw);
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}
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set_visited_fwd(t, next_idx, dh);
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}
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if (t.fwd_queue.empty()) {
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return false;
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} else {
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curr = t.fwd_queue.top();
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t.fwd_queue.pop();
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}
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}
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return true;
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};
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auto backtrack = [&](){
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auto& unexplored_best = t.bwd_queue.top();
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auto unexplored_best_score = t.bwd_queue.empty() ? std::numeric_limits<float>::max() : unexplored_best.score.total();
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if (!low_prio.empty()) {
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auto p = std::partition(low_prio.begin(), low_prio.end(), [=](QueuedWire w) { return w.score.total() > unexplored_best_score; });
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for (auto it = p; it != low_prio.end(); it++) {
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//log("bt: wire %s -> G\n", ctx->getWireName(flat_wires.at(it->wire).w).str(ctx).c_str());
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t.bwd_queue.push(*it);
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}
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if (t.bwd_queue.empty()) {
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auto greater = [](const QueuedWire &lhs, const QueuedWire &rhs) {
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float lhs_score = lhs.score.total(),
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rhs_score = rhs.score.total();
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return lhs_score == rhs_score ? lhs.randtag > rhs.randtag : lhs_score > rhs_score;
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};
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std::nth_element(low_prio.begin(), low_prio.end()-1, low_prio.end(), greater);
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std::nth_element(low_prio.begin(), low_prio.end()-2, low_prio.end(), greater);
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std::nth_element(low_prio.begin(), low_prio.end()-3, low_prio.end(), greater);
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t.bwd_queue.push(*(low_prio.end()-1));
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t.bwd_queue.push(*(low_prio.end()-2));
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t.bwd_queue.push(*(low_prio.end()-3));
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p = low_prio.end() - 3;
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}
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low_prio.erase(p, low_prio.end());
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}
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NPNR_ASSERT(!t.bwd_queue.empty());
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auto curr = t.bwd_queue.top();
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t.bwd_queue.pop();
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NPNR_ASSERT(curr.wire < flat_wires.size());
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return curr;
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};
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WireScore next_score;
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next_score.criticality = crit;
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next_score.congest = 0.0;
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next_score.delay = 0.0;
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next_score.togo = get_togo_cost(net, i, src_wire_idx, dst_wire, false, crit_weight);
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auto curr = QueuedWire(src_wire_idx, next_score, t.rng.rng());
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NPNR_ASSERT(curr.wire < flat_wires.size());
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bool done = false;
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int fs_calls = 0;
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int bt_calls = 0;
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while (!done) {
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fs_calls++;
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done = fast_search(curr);
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if (!done) {
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if (t.bwd_queue.empty() && low_prio.empty()) {
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reset_wires(t);
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//log("fail; %d fs calls, %d bt calls\n", fs_calls, bt_calls);
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return ARC_RETRY_WITHOUT_BB;
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} else {
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curr = backtrack();
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bt_calls++;
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}
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}
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}
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int cursor_bwd = dst_wire_idx;
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while (was_visited_fwd(cursor_bwd)) {
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PipId pip = flat_wires.at(cursor_bwd).pip_fwd;
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if (pip == PipId() && cursor_bwd != src_wire_idx)
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break;
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bind_pip_internal(nd, i, cursor_bwd, pip);
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if (ctx->debug && !is_mt) {
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auto &wd = flat_wires.at(cursor_bwd);
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ROUTE_LOG_DBG(" fwd wire: %s (curr %d hist %f share %d)\n", ctx->nameOfWire(wd.w),
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wd.curr_cong - 1, wd.hist_cong_cost, nd.wires.at(wd.w).second);
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}
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if (pip == PipId()) {
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break;
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}
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ROUTE_LOG_DBG(" fwd pip: %s (%d, %d)\n", ctx->nameOfPip(pip), ctx->getPipLocation(pip).x,
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ctx->getPipLocation(pip).y);
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cursor_bwd = wire_to_idx.at(ctx->getPipSrcWire(pip));
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}
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reset_wires(t);
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//log("done; %d fs calls, %d bt calls\n", fs_calls, bt_calls);
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return ARC_SUCCESS;
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}
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ArcRouteResult route_arc(ThreadContext &t, NetInfo *net, store_index<PortRef> i, size_t phys_pin, bool is_mt,
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bool is_bb = true)
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{
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@ -910,7 +1158,7 @@ struct Router2
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return get_arc_crit(net, a.first) > get_arc_crit(net, b.first);
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});
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for (auto a : t.route_arcs) {
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auto res1 = route_arc(t, net, a.first, a.second, is_mt, true);
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auto res1 = route_arc_lofty(t, net, a.first, a.second, is_mt, true);
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if (res1 == ARC_FATAL)
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return false; // Arc failed irrecoverably
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else if (res1 == ARC_RETRY_WITHOUT_BB) {
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@ -921,7 +1169,7 @@ struct Router2
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// Attempt a re-route without the bounding box constraint
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ROUTE_LOG_DBG("Rerouting arc %d.%d of net '%s' without bounding box, possible tricky routing...\n",
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a.first.idx(), int(a.second), ctx->nameOf(net));
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auto res2 = route_arc(t, net, a.first, a.second, is_mt, false);
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auto res2 = route_arc_lofty(t, net, a.first, a.second, is_mt, false);
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// If this also fails, no choice but to give up
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if (res2 != ARC_SUCCESS) {
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if (ctx->debug) {
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