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Merge pull request #697 from YosysHQ/gatecat/router2-dynamic-bb-expand

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router2: Dynamicly expand bounding box based on congestion
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gatecat 2021-05-06 22:05:04 +01:00 committed by GitHub
commit 3144e83950
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1 changed files with 61 additions and 23 deletions
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84
common/router2.cc
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@ -68,6 +68,7 @@ struct Router2
int cx, cy, hpwl;
int total_route_us = 0;
float max_crit = 0;
int fail_count = 0;
};
struct WireScore
@ -189,6 +190,10 @@ struct Router2
log_info("%s: bb=(%d, %d)->(%d, %d) c=(%d, %d) hpwl=%d\n", ctx->nameOf(ni), nets.at(i).bb.x0,
nets.at(i).bb.y0, nets.at(i).bb.x1, nets.at(i).bb.y1, nets.at(i).cx, nets.at(i).cy,
nets.at(i).hpwl);
nets.at(i).bb.x0 = std::max(nets.at(i).bb.x0 - cfg.bb_margin_x, 0);
nets.at(i).bb.y0 = std::max(nets.at(i).bb.y0 - cfg.bb_margin_y, 0);
nets.at(i).bb.x1 = std::min(nets.at(i).bb.x1 + cfg.bb_margin_x, ctx->getGridDimX());
nets.at(i).bb.y1 = std::min(nets.at(i).bb.y1 + cfg.bb_margin_y, ctx->getGridDimY());
i++;
}
}
@ -264,11 +269,7 @@ struct Router2
};
};
bool hit_test_pip(ArcBounds &bb, Loc l)
{
return l.x >= (bb.x0 - cfg.bb_margin_x) && l.x <= (bb.x1 + cfg.bb_margin_x) &&
l.y >= (bb.y0 - cfg.bb_margin_y) && l.y <= (bb.y1 + cfg.bb_margin_y);
}
bool hit_test_pip(ArcBounds &bb, Loc l) { return l.x >= bb.x0 && l.x <= bb.x1 && l.y >= bb.y0 && l.y <= bb.y1; }
double curr_cong_weight, hist_cong_weight, estimate_weight;
@ -433,20 +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;
@ -458,13 +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;
@ -477,17 +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)
@ -684,7 +707,7 @@ struct Router2
if (is_bb && !hit_test_pip(ad.bb, ctx->getPipLocation(dh)) && wire_intent != ID_PSEUDO_GND && wire_intent != ID_PSEUDO_VCC)
continue;
#else
if (is_bb && !hit_test_pip(ad.bb, ctx->getPipLocation(dh)))
if (is_bb && !hit_test_pip(nd.bb, ctx->getPipLocation(dh)))
continue;
if (!ctx->checkPipAvailForNet(dh, net)) {
ROUTE_LOG_DBG("Skipping pip %s because it is bound to net '%s' not net '%s'\n", ctx->nameOfPip(dh),
@ -719,6 +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",
@ -727,6 +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;
@ -808,7 +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;
}
@ -870,6 +897,17 @@ struct Router2
failed_nets.insert(bound.first);
}
}
for (int n : failed_nets) {
auto &net_data = nets.at(n);
++net_data.fail_count;
if ((net_data.fail_count % 3) == 0) {
// Every three times a net fails to route, expand the bounding box to increase the search space
net_data.bb.x0 = std::max(net_data.bb.x0 - 1, 0);
net_data.bb.y0 = std::max(net_data.bb.y0 - 1, 0);
net_data.bb.x1 = std::min(net_data.bb.x1 + 1, ctx->getGridDimX());
net_data.bb.y1 = std::min(net_data.bb.y1 + 1, ctx->getGridDimY());
}
}
}
bool bind_and_check(NetInfo *net, int usr_idx, int phys_pin)
@ -1113,10 +1151,10 @@ struct Router2
for (auto &th : tcs) {
th.rng.rngseed(ctx->rng64());
}
int le_x = mid_x - cfg.bb_margin_x;
int rs_x = mid_x + cfg.bb_margin_x;
int le_y = mid_y - cfg.bb_margin_y;
int rs_y = mid_y + cfg.bb_margin_y;
int le_x = mid_x;
int rs_x = mid_x;
int le_y = mid_y;
int rs_y = mid_y;
// Set up thread bounding boxes
tcs.at(0).bb = ArcBounds(0, 0, mid_x, mid_y);
tcs.at(1).bb = ArcBounds(mid_x + 1, 0, std::numeric_limits<int>::max(), le_y);