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router2: A* main loop

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2019-11-08 17:42:08 +00:00
parent dbb771dfe4
commit 37d5775694
1 changed files with 81 additions and 9 deletions
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90
common/router2.cc
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@ -202,10 +202,15 @@ struct Router2
double curr_cong_weight, hist_cong_weight, estimate_weight;
// Soft-route a net (don't touch Arch data structures which might not be thread safe)
// If is_mt is true, then strict bounding box rules are applied and log_* won't be called
struct VisitInfo
{
WireScore score;
PipId pip;
};
struct ThreadContext
{
std::priority_queue<QueuedWire, std::vector<QueuedWire>, QueuedWire::Greater> queue;
std::unordered_map<WireId, QueuedWire> visited;
std::unordered_map<WireId, VisitInfo> visited;
};
enum ArcRouteResult
@ -280,8 +285,21 @@ struct Router2
return base_cost * hist_cost * present_cost / (1 + source_uses) + bias_cost;
}
float get_togo_cost(NetInfo *net, size_t user, WireId wire, WireId sink)
{
auto &wd = wires.at(wire);
int source_uses = 0;
if (wd.bound_nets.count(net->udata))
source_uses = wd.bound_nets.at(net->udata).first;
// FIXME: timing/wirelength balance?
return ctx->getDelayNS(ctx->estimateDelay(wire, sink)) / (1 + source_uses);
}
ArcRouteResult route_arc(ThreadContext &t, NetInfo *net, size_t i, bool is_mt, bool is_bb = true)
{
auto &nd = nets[net->udata];
auto &ad = nd.arcs[i];
auto &usr = net->users.at(i);
ROUTE_LOG_DBG("Routing arc %d of net '%s'", int(i), ctx->nameOf(net));
WireId src_wire = ctx->getNetinfoSourceWire(net), dst_wire = ctx->getNetinfoSinkWire(net, usr);
@ -292,20 +310,74 @@ struct Router2
if (dst_wire == WireId())
ARC_LOG_ERR("No wire found for port %s on destination cell %s.\n", ctx->nameOf(usr.port),
ctx->nameOf(usr.cell));
// Ripup arc to start with
ripup_arc(net, i);
bind_pip_internal(net, i, src_wire, PipId());
return ARC_SUCCESS;
}
#undef ARC_ERR
bool route_net(ThreadContext &t, NetInfo *net, bool is_mt)
{
ROUTE_LOG_DBG("Routing net '%s'...\n", ctx->nameOf(net));
if (!t.queue.empty()) {
std::priority_queue<QueuedWire, std::vector<QueuedWire>, QueuedWire::Greater> new_queue;
t.queue.swap(new_queue);
}
t.visited.clear();
// Add source wire to queue
WireScore base_score;
base_score.cost = 0;
base_score.delay = ctx->getWireDelay(src_wire).maxDelay();
base_score.togo_cost = get_togo_cost(net, i, src_wire, dst_wire);
t.queue.push(QueuedWire(src_wire, PipId(), Loc(), base_score));
t.visited[src_wire].score = base_score;
t.visited[src_wire].pip = PipId();
while (!t.queue.empty()) {
auto curr = t.queue.top();
t.queue.pop();
// Explore all pips downhill of cursor
for (auto dh : ctx->getPipsDownhill(curr.wire)) {
// Skip pips outside of box in bounding-box mode
if (is_bb && !hit_test_pip(ad.bb, ctx->getPipLocation(dh)))
continue;
// Evaluate score of next wire
WireId next = ctx->getPipSrcWire(dh);
WireScore next_score;
next_score.cost = curr.score.cost + score_wire_for_arc(net, i, next, dh);
next_score.delay =
curr.score.delay + ctx->getPipDelay(dh).maxDelay() + ctx->getWireDelay(next).maxDelay();
next_score.togo_cost = get_togo_cost(net, i, next, dst_wire);
if (!t.visited.count(next) || (t.visited.at(next).score.total() > next_score.total())) {
// Add wire to queue if it meets criteria
t.queue.push(QueuedWire(next, dh, ctx->getPipLocation(dh), next_score, ctx->rng()));
t.visited[next].score = next_score;
t.visited[next].pip = dh;
if (next == dst_wire)
goto loop_done;
}
}
if (0) {
loop_done:
break;
}
}
if (t.visited.count(dst_wire)) {
WireId cursor_bwd = dst_wire;
while (t.visited.count(cursor_bwd)) {
auto &v = t.visited.at(cursor_bwd);
bind_pip_internal(net, i, cursor_bwd, v.pip);
if (v.pip == PipId()) {
NPNR_ASSERT(cursor_bwd == src_wire);
break;
}
cursor_bwd = ctx->getPipSrcWire(v.pip);
}
return ARC_SUCCESS;
} else {
return ARC_RETRY_WITHOUT_BB;
}
}
#undef ARC_ERR
bool route_net(ThreadContext &t, NetInfo *net, bool is_mt)
{
ROUTE_LOG_DBG("Routing net '%s'...\n", ctx->nameOf(net));
bool have_failures = false;
for (size_t i = 0; i < net->users.size(); i++) {
auto res1 = route_arc(t, net, i, is_mt, true);