diff options
Diffstat (limited to 'common/router2.cc')
-rw-r--r-- | common/router2.cc | 52 |
1 files changed, 39 insertions, 13 deletions
diff --git a/common/router2.cc b/common/router2.cc index 24bccec7..b62873c0 100644 --- a/common/router2.cc +++ b/common/router2.cc @@ -434,20 +434,35 @@ struct Router2 } // Returns true if a wire contains no source ports or driving pips - bool is_wire_undriveable(WireId wire) + bool is_wire_undriveable(WireId wire, const NetInfo *net, int iter_count = 0) { + // This is specifically designed to handle a particularly icky case that the current router struggles with in + // the nexus device, + // C -> C lut input only + // C; D; or F from another lut -> D lut input + // D or M -> M ff input + // without careful reservation of C for C lut input and D for D lut input, there is fighting for D between FF + // and LUT + if (iter_count > 7) + return false; // heuristic to assume we've hit general routing + if (wire_data(wire).reserved_net != -1 && wire_data(wire).reserved_net != net->udata) + return true; // reserved for another net for (auto bp : ctx->getWireBelPins(wire)) - if (ctx->getBelPinType(bp.bel, bp.pin) != PORT_IN) + if ((net->driver.cell == nullptr || bp.bel == net->driver.cell->bel) && + ctx->getBelPinType(bp.bel, bp.pin) != PORT_IN) return false; for (auto p : ctx->getPipsUphill(wire)) - if (ctx->checkPipAvail(p)) - return false; + if (ctx->checkPipAvail(p)) { + if (!is_wire_undriveable(ctx->getPipSrcWire(p), net, iter_count + 1)) + return false; + } return true; } // Find all the wires that must be used to route a given arc - void reserve_wires_for_arc(NetInfo *net, size_t i) + bool reserve_wires_for_arc(NetInfo *net, size_t i) { + bool did_something = false; WireId src = ctx->getNetinfoSourceWire(net); for (auto sink : ctx->getNetinfoSinkWires(net, net->users.at(i))) { std::unordered_set<WireId> rsv; @@ -459,13 +474,14 @@ struct Router2 auto &wd = wire_data(cursor); if (ctx->debug) log(" %s\n", ctx->nameOfWire(cursor)); + did_something |= (wd.reserved_net != net->udata); wd.reserved_net = net->udata; if (cursor == src) break; WireId next_cursor; for (auto uh : ctx->getPipsUphill(cursor)) { WireId w = ctx->getPipSrcWire(uh); - if (is_wire_undriveable(w)) + if (is_wire_undriveable(w, net)) continue; if (next_cursor != WireId()) { done = true; @@ -478,17 +494,23 @@ struct Router2 cursor = next_cursor; } } + return did_something; } void find_all_reserved_wires() { - for (auto net : nets_by_udata) { - WireId src = ctx->getNetinfoSourceWire(net); - if (src == WireId()) - continue; - for (size_t i = 0; i < net->users.size(); i++) - reserve_wires_for_arc(net, i); - } + // Run iteratively, as reserving wires for one net might limit choices for another + bool did_something = false; + do { + did_something = false; + for (auto net : nets_by_udata) { + WireId src = ctx->getNetinfoSourceWire(net); + if (src == WireId()) + continue; + for (size_t i = 0; i < net->users.size(); i++) + did_something |= reserve_wires_for_arc(net, i); + } + } while (did_something); } void reset_wires(ThreadContext &t) @@ -720,6 +742,7 @@ struct Router2 next_score.delay = curr.score.delay + ctx->getPipDelay(dh).maxDelay() + ctx->getWireDelay(next).maxDelay(); next_score.togo_cost = cfg.estimate_weight * get_togo_cost(net, i, next_idx, dst_wire, &forward); +#if 0 ROUTE_LOG_DBG( "src_wire = %s -> next %s -> dst_wire = %s (backward: %s, forward: %s, sum: %s, cost = %f, " "togo_cost = %f, total = %f), dt = %02fs\n", @@ -728,6 +751,7 @@ struct Router2 std::to_string(next_score.delay + forward).c_str(), next_score.cost, next_score.togo_cost, next_score.cost + next_score.togo_cost, std::chrono::duration<float>(std::chrono::high_resolution_clock::now() - arc_start).count()); +#endif const auto &v = nwd.visit; if (!v.visited || (v.score.total() > next_score.total())) { ++explored; @@ -809,7 +833,9 @@ struct Router2 // Ripup failed arcs to start with // Check if arc is already legally routed if (check_arc_routing(net, i, j)) { +#if 0 ROUTE_LOG_DBG("Arc '%s' (user %zu, arc %zu) already routed skipping.\n", ctx->nameOf(net), i, j); +#endif continue; } |