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wip midpoint revisit

This commit is contained in:
gatecat 2026-08-14 17:10:00 +02:00
parent 3d71bf678c
commit 9b117b8b95
1 changed files with 40 additions and 14 deletions
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54
common/route/router2.cc
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@ -836,6 +836,8 @@ struct Router2
float best_midpoint_cost = 0; float best_midpoint_cost = 0;
int explored = 1; int explored = 1;
float est_cost = ctx->getDelayNS(std::max(ctx->estimateDelay(src_wire, dst_wire), ctx->getDelayEpsilon()));
for (; mode < 2; mode++) { for (; mode < 2; mode++) {
// Clear out the queues // Clear out the queues
if (!t.fwd_queue.empty()) { if (!t.fwd_queue.empty()) {
@ -910,12 +912,25 @@ struct Router2
auto curr = t.fwd_queue.top(); auto curr = t.fwd_queue.top();
t.fwd_queue.pop(); t.fwd_queue.pop();
++explored; ++explored;
if (was_visited_bwd(curr.wire, std::numeric_limits<float>::max())) {
// Meet in the middle; done
midpoint_wire = curr.wire;
break;
}
auto &curr_data = flat_wires.at(curr.wire); auto &curr_data = flat_wires.at(curr.wire);
if (was_visited_bwd(curr.wire, std::numeric_limits<float>::max())) {
auto total_cost = curr_data.cost_fwd + curr_data.cost_bwd;
if (midpoint_wire == -1) {
midpoint_wire = curr.wire;
best_midpoint_cost = total_cost;
toexplore = iter + std::min(1000, 20 * int(total_cost / est_cost));
} else if (total_cost < best_midpoint_cost) {
midpoint_wire = curr.wire;
best_midpoint_cost = total_cost;
// keep exploring while we find better solutions
toexplore = iter + std::min(1000, 20 * int(total_cost / est_cost));
}
// Never allow the forward and backward router to intersect, this could result in loops
continue;
}
for (PipId dh : ctx->getPipsDownhill(curr_data.w)) { for (PipId dh : ctx->getPipsDownhill(curr_data.w)) {
// Skip pips outside of box in bounding-box mode // Skip pips outside of box in bounding-box mode
if (is_bb && !hit_test_pip(nd.bb, ctx->getPipLocation(dh))) if (is_bb && !hit_test_pip(nd.bb, ctx->getPipLocation(dh)))
@ -926,10 +941,10 @@ struct Router2
int next_idx = wire_to_idx.at(next); int next_idx = wire_to_idx.at(next);
WireScore next_score; WireScore next_score;
next_score.delay = curr.score.delay + cfg.get_base_cost(ctx, next, dh, crit_weight); next_score.delay = curr.score.delay + cfg.get_base_cost(ctx, next, dh, crit_weight);
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, phys_pin, next, dh, crit_weight); next_score.cost = curr_data.cost_fwd + score_wire_for_arc(net, i, phys_pin, next, dh, crit_weight);
next_score.togo_cost = next_score.togo_cost =
cfg.estimate_weight * get_togo_cost(net, i, next_idx, dst_wire, false, crit_weight); cfg.estimate_weight * get_togo_cost(net, i, next_idx, dst_wire, false, crit_weight);
if (was_visited_fwd(next_idx, next_score.delay)) { if (was_visited_fwd(next_idx, next_score.cost)) {
// Don't expand the same node twice. // Don't expand the same node twice.
continue; continue;
} }
@ -953,7 +968,7 @@ struct Router2
} }
if (!thread_test_wire(t, nwd)) if (!thread_test_wire(t, nwd))
continue; // thread safety issue continue; // thread safety issue
set_visited_fwd(t, next_idx, dh, next_score.delay); set_visited_fwd(t, next_idx, dh, next_score.cost);
t.fwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng())); t.fwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng()));
} }
} }
@ -979,9 +994,20 @@ struct Router2
} }
} else { } else {
if (was_visited_fwd(curr.wire, std::numeric_limits<float>::max())) { if (was_visited_fwd(curr.wire, std::numeric_limits<float>::max())) {
// Meet in the middle; done auto total_cost = curr_data.cost_bwd + curr_data.cost_fwd;
midpoint_wire = curr.wire; if (midpoint_wire == -1) {
break; midpoint_wire = curr.wire;
best_midpoint_cost = total_cost;
toexplore = iter + std::min(1000, 20 * int(total_cost / est_cost));
} else if (total_cost < best_midpoint_cost) {
midpoint_wire = curr.wire;
best_midpoint_cost = total_cost;
// keep exploring while we find better solutions
toexplore = iter + std::min(1000, 20 * int(total_cost / est_cost));
}
// Never allow the forward and backward router to intersect, this could result in loops
continue;
} }
} }
// Don't allow the same wire to be bound to the same net with a different driving pip // Don't allow the same wire to be bound to the same net with a different driving pip
@ -1001,12 +1027,12 @@ struct Router2
int next_idx = wire_to_idx.at(next); int next_idx = wire_to_idx.at(next);
WireScore next_score; WireScore next_score;
next_score.delay = curr.score.delay + cfg.get_base_cost(ctx, next, uh, crit_weight); next_score.delay = curr.score.delay + cfg.get_base_cost(ctx, next, uh, crit_weight);
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, phys_pin, next, uh, crit_weight); next_score.cost = curr_data.cost_bwd + score_wire_for_arc(net, i, phys_pin, next, uh, crit_weight);
next_score.togo_cost = const_mode next_score.togo_cost = const_mode
? 0 ? 0
: cfg.estimate_weight * get_togo_cost(net, i, next_idx, src_wire, : cfg.estimate_weight * get_togo_cost(net, i, next_idx, src_wire,
true, crit_weight); true, crit_weight);
if (was_visited_bwd(next_idx, next_score.delay)) { if (was_visited_bwd(next_idx, next_score.cost)) {
// Don't expand the same node twice. // Don't expand the same node twice.
continue; continue;
} }
@ -1026,7 +1052,7 @@ struct Router2
} }
if (!thread_test_wire(t, nwd)) if (!thread_test_wire(t, nwd))
continue; // thread safety issue continue; // thread safety issue
set_visited_bwd(t, next_idx, uh, next_score.delay); set_visited_bwd(t, next_idx, uh, next_score.cost);
t.bwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng())); t.bwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng()));
} }
} }