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router2: revisit nodes with lower cost

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This commit is contained in:
Lofty 2023-06-13 00:47:07 +01:00
parent 863ad4cee8
commit 8935c1867f
1 changed files with 28 additions and 23 deletions
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51
common/route/router2.cc
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@ -94,6 +94,7 @@ struct Router2
// Visit data // Visit data
PipId pip_fwd, pip_bwd; PipId pip_fwd, pip_bwd;
bool visited_fwd = false, visited_bwd = false; bool visited_fwd = false, visited_bwd = false;
float cost_fwd = 0.0, cost_bwd = 0.0;
}; };
Context *ctx; Context *ctx;
@ -522,6 +523,8 @@ struct Router2
flat_wires[w].pip_bwd = PipId(); flat_wires[w].pip_bwd = PipId();
flat_wires[w].visited_fwd = false; flat_wires[w].visited_fwd = false;
flat_wires[w].visited_bwd = false; flat_wires[w].visited_bwd = false;
flat_wires[w].cost_fwd = 0.0;
flat_wires[w].cost_bwd = 0.0;
} }
t.dirty_wires.clear(); t.dirty_wires.clear();
} }
@ -559,25 +562,27 @@ struct Router2
} }
// Functions for marking wires as visited, and checking if they have already been visited // Functions for marking wires as visited, and checking if they have already been visited
void set_visited_fwd(ThreadContext &t, int wire, PipId pip) void set_visited_fwd(ThreadContext &t, int wire, PipId pip, float cost)
{ {
auto &wd = flat_wires.at(wire); auto &wd = flat_wires.at(wire);
if (!wd.visited_fwd && !wd.visited_bwd) if (!wd.visited_fwd && !wd.visited_bwd)
t.dirty_wires.push_back(wire); t.dirty_wires.push_back(wire);
wd.pip_fwd = pip; wd.pip_fwd = pip;
wd.visited_fwd = true; wd.visited_fwd = true;
wd.cost_fwd = cost;
} }
void set_visited_bwd(ThreadContext &t, int wire, PipId pip) void set_visited_bwd(ThreadContext &t, int wire, PipId pip, float cost)
{ {
auto &wd = flat_wires.at(wire); auto &wd = flat_wires.at(wire);
if (!wd.visited_fwd && !wd.visited_bwd) if (!wd.visited_fwd && !wd.visited_bwd)
t.dirty_wires.push_back(wire); t.dirty_wires.push_back(wire);
wd.pip_bwd = pip; wd.pip_bwd = pip;
wd.visited_bwd = true; wd.visited_bwd = true;
wd.cost_bwd = cost;
} }
bool was_visited_fwd(int wire) { return flat_wires.at(wire).visited_fwd; } bool was_visited_fwd(int wire, float cost) { return flat_wires.at(wire).visited_fwd && flat_wires.at(wire).cost_fwd <= cost; }
bool was_visited_bwd(int wire) { return flat_wires.at(wire).visited_bwd; } bool was_visited_bwd(int wire, float cost) { return flat_wires.at(wire).visited_bwd && flat_wires.at(wire).cost_bwd <= cost; }
float get_arc_crit(NetInfo *net, store_index<PortRef> i) float get_arc_crit(NetInfo *net, store_index<PortRef> i)
{ {
@ -652,7 +657,7 @@ struct Router2
int wire_idx = wire_to_idx.at(wire); int wire_idx = wire_to_idx.at(wire);
base_score.togo_cost = get_togo_cost(net, i, wire_idx, dst_wire, false, crit_weight); base_score.togo_cost = get_togo_cost(net, i, wire_idx, dst_wire, false, crit_weight);
t.fwd_queue.push(QueuedWire(wire_idx, base_score)); t.fwd_queue.push(QueuedWire(wire_idx, base_score));
set_visited_fwd(t, wire_idx, PipId()); set_visited_fwd(t, wire_idx, PipId(), 0.0);
}; };
auto &dst_data = flat_wires.at(dst_wire_idx); auto &dst_data = flat_wires.at(dst_wire_idx);
// Look for nearby existing routing // Look for nearby existing routing
@ -674,7 +679,7 @@ struct Router2
// Seed forwards with the source wire, if less than 8 existing wires added // Seed forwards with the source wire, if less than 8 existing wires added
seed_queue_fwd(src_wire); seed_queue_fwd(src_wire);
} else { } else {
set_visited_fwd(t, src_wire_idx, PipId()); set_visited_fwd(t, src_wire_idx, PipId(), 0.0);
} }
auto seed_queue_bwd = [&](WireId wire) { auto seed_queue_bwd = [&](WireId wire) {
WireScore base_score; WireScore base_score;
@ -682,7 +687,7 @@ struct Router2
int wire_idx = wire_to_idx.at(wire); int wire_idx = wire_to_idx.at(wire);
base_score.togo_cost = get_togo_cost(net, i, wire_idx, src_wire, true, crit_weight); base_score.togo_cost = get_togo_cost(net, i, wire_idx, src_wire, true, crit_weight);
t.bwd_queue.push(QueuedWire(wire_idx, base_score)); t.bwd_queue.push(QueuedWire(wire_idx, base_score));
set_visited_bwd(t, wire_idx, PipId()); set_visited_bwd(t, wire_idx, PipId(), 0.0);
}; };
// Seed backwards with the dest wire // Seed backwards with the dest wire
@ -701,7 +706,7 @@ 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)) { if (was_visited_bwd(curr.wire, FLT_MAX)) {
// Meet in the middle; done // Meet in the middle; done
midpoint_wire = curr.wire; midpoint_wire = curr.wire;
break; break;
@ -715,7 +720,11 @@ struct Router2
continue; continue;
WireId next = ctx->getPipDstWire(dh); WireId next = ctx->getPipDstWire(dh);
int next_idx = wire_to_idx.at(next); int next_idx = wire_to_idx.at(next);
if (was_visited_fwd(next_idx)) { WireScore next_score;
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, phys_pin, next, dh, crit_weight);
next_score.togo_cost =
cfg.estimate_weight * get_togo_cost(net, i, next_idx, dst_wire, false, crit_weight);
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;
} }
@ -731,11 +740,7 @@ struct Router2
continue; continue;
if (!thread_test_wire(t, nwd)) if (!thread_test_wire(t, nwd))
continue; // thread safety issue continue; // thread safety issue
WireScore next_score; set_visited_fwd(t, next_idx, dh, next_score.cost);
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, phys_pin, next, dh, crit_weight);
next_score.togo_cost =
cfg.estimate_weight * get_togo_cost(net, i, next_idx, dst_wire, false, crit_weight);
set_visited_fwd(t, next_idx, dh);
t.fwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng())); t.fwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng()));
} }
} }
@ -744,7 +749,7 @@ struct Router2
auto curr = t.bwd_queue.top(); auto curr = t.bwd_queue.top();
t.bwd_queue.pop(); t.bwd_queue.pop();
++explored; ++explored;
if (was_visited_fwd(curr.wire)) { if (was_visited_fwd(curr.wire, FLT_MAX)) {
// Meet in the middle; done // Meet in the middle; done
midpoint_wire = curr.wire; midpoint_wire = curr.wire;
break; break;
@ -765,7 +770,11 @@ struct Router2
continue; continue;
WireId next = ctx->getPipSrcWire(uh); WireId next = ctx->getPipSrcWire(uh);
int next_idx = wire_to_idx.at(next); int next_idx = wire_to_idx.at(next);
if (was_visited_bwd(next_idx)) { WireScore next_score;
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, phys_pin, next, uh, crit_weight);
next_score.togo_cost =
cfg.estimate_weight * get_togo_cost(net, i, next_idx, src_wire, true, crit_weight);
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;
} }
@ -777,11 +786,7 @@ struct Router2
continue; continue;
if (!thread_test_wire(t, nwd)) if (!thread_test_wire(t, nwd))
continue; // thread safety issue continue; // thread safety issue
WireScore next_score; set_visited_bwd(t, next_idx, uh, next_score.cost);
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, phys_pin, next, uh, crit_weight);
next_score.togo_cost =
cfg.estimate_weight * get_togo_cost(net, i, next_idx, src_wire, true, crit_weight);
set_visited_bwd(t, next_idx, uh);
t.bwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng())); t.bwd_queue.push(QueuedWire(next_idx, next_score, t.rng.rng()));
} }
} }
@ -793,7 +798,7 @@ struct Router2
if (midpoint_wire != -1) { if (midpoint_wire != -1) {
ROUTE_LOG_DBG(" Routed (explored %d wires): ", explored); ROUTE_LOG_DBG(" Routed (explored %d wires): ", explored);
int cursor_bwd = midpoint_wire; int cursor_bwd = midpoint_wire;
while (was_visited_fwd(cursor_bwd)) { while (was_visited_fwd(cursor_bwd, FLT_MAX)) {
PipId pip = flat_wires.at(cursor_bwd).pip_fwd; PipId pip = flat_wires.at(cursor_bwd).pip_fwd;
if (pip == PipId() && cursor_bwd != src_wire_idx) if (pip == PipId() && cursor_bwd != src_wire_idx)
break; break;
@ -832,7 +837,7 @@ struct Router2
NPNR_ASSERT(cursor_bwd == src_wire_idx); NPNR_ASSERT(cursor_bwd == src_wire_idx);
int cursor_fwd = midpoint_wire; int cursor_fwd = midpoint_wire;
while (was_visited_bwd(cursor_fwd)) { while (was_visited_bwd(cursor_fwd, FLT_MAX)) {
PipId pip = flat_wires.at(cursor_fwd).pip_bwd; PipId pip = flat_wires.at(cursor_fwd).pip_bwd;
if (pip == PipId()) { if (pip == PipId()) {
break; break;