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router2: delay-based lookahead prototype

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This commit is contained in:
Lofty 2024-05-03 08:36:48 +01:00
parent edcafcf085
commit e044d00a24
1 changed files with 153 additions and 4 deletions
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157
common/route/router2.cc
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@ -255,6 +255,154 @@ struct Router2
bool hit_test_pip(BoundingBox &bb, Loc l) { return l.x >= bb.x0 && l.x <= bb.x1 && l.y >= bb.y0 && l.y <= bb.y1; }
std::mutex delay_lookahead_mutex;
dict<IdString, dict<IdString, std::vector<delay_t>>> delay_lookahead;
dict<IdString, pool<IdString>> lookahead_learning_complete;
int total_lookahead_calc_us = 0;
void compute_delay_lookahead(WireId src, WireId dst) {
std::priority_queue<QueuedWire, std::vector<QueuedWire>, QueuedWire::Greater> queue;
pool<WireId> visited;
auto src_type = ctx->getWireType(src);
auto dst_type = ctx->getWireType(dst);
// Are we likely to gain anything from another round of search?
if (lookahead_learning_complete.count(src_type) == 0)
lookahead_learning_complete.insert({src_type, pool<IdString>{}});
if (lookahead_learning_complete.at(src_type).count(dst_type) != 0)
return;
auto setup = [&](WireId s, WireId d) {
auto s_type = ctx->getWireType(s);
auto d_type = ctx->getWireType(d);
if (delay_lookahead.count(s_type) == 0)
delay_lookahead.insert({s_type, dict<IdString, std::vector<delay_t>>{}});
if (delay_lookahead.at(s_type).count(d_type) == 0)
delay_lookahead.at(s_type).insert({d_type, std::vector<delay_t>((ctx->getGridDimX() + 1)*(ctx->getGridDimY() + 1), ctx->getDelayFromNS(1000.0))});
};
auto start_time = std::chrono::high_resolution_clock::now();
setup(src, dst);
auto sd_bb = ctx->getRouteBoundingBox(src, dst);
auto sd_dx = std::abs(sd_bb.x1 - sd_bb.x0);
auto sd_dy = std::abs(sd_bb.y1 - sd_bb.y0);
{
WireScore score;
score.delay = 0;
score.cost = 0;
score.togo_cost = 0;
queue.push(QueuedWire(wire_to_idx.at(src), score));
}
int updates = 0;
while (!queue.empty()) {
auto w = queue.top();
queue.pop();
for (auto dh : ctx->getPipsDownhill(flat_wires.at(w.wire).w)) {
auto wire = ctx->getPipDstWire(dh);
auto wire_type = ctx->getWireType(wire);
if (visited.count(wire))
continue;
visited.insert(wire);
auto bb = ctx->getRouteBoundingBox(src, wire);
auto dx = std::min(std::abs(bb.x1 - bb.x0), ctx->getGridDimX());
auto dy = std::min(std::abs(bb.y1 - bb.y0), ctx->getGridDimY());
auto delay = w.score.cost;
setup(src, wire);
auto lookahead_delay = delay_lookahead.at(src_type).at(wire_type).at((ctx->getGridDimX() + 1)*dy + dx);
updates += lookahead_delay > ctx->getDelayFromNS(delay);
delay_lookahead.at(src_type).at(wire_type).at((ctx->getGridDimX() + 1)*dy + dx) = std::min(lookahead_delay, ctx->getDelayFromNS(delay));
setup(wire, src);
lookahead_delay = delay_lookahead.at(wire_type).at(src_type).at((ctx->getGridDimX() + 1)*dy + dx);
updates += lookahead_delay > ctx->getDelayFromNS(delay);
delay_lookahead.at(wire_type).at(src_type).at((ctx->getGridDimX() + 1)*dy + dx) = std::min(lookahead_delay, ctx->getDelayFromNS(delay));
WireScore score;
score.delay = 0;
score.cost = delay + cfg.get_base_cost(ctx, wire, dh, 1.0);
score.togo_cost = 0;
queue.push(QueuedWire(wire_to_idx.at(wire), score));
}
}
{
WireScore score;
score.delay = 0;
score.cost = 0;
score.togo_cost = 0;
queue.push(QueuedWire(wire_to_idx.at(src), score));
}
while (!queue.empty()) {
auto w = queue.top();
queue.pop();
for (auto uh : ctx->getPipsUphill(flat_wires.at(w.wire).w)) {
auto wire = ctx->getPipSrcWire(uh);
auto wire_type = ctx->getWireType(wire);
if (visited.count(wire))
continue;
visited.insert(wire);
auto bb = ctx->getRouteBoundingBox(src, wire);
auto dx = std::min(std::abs(bb.x1 - bb.x0), ctx->getGridDimX());
auto dy = std::min(std::abs(bb.y1 - bb.y0), ctx->getGridDimY());
auto delay = w.score.cost;
setup(src, wire);
auto lookahead_delay = delay_lookahead.at(src_type).at(wire_type).at((ctx->getGridDimX() + 1)*dy + dx);
updates += lookahead_delay > ctx->getDelayFromNS(delay);
delay_lookahead.at(src_type).at(wire_type).at((ctx->getGridDimX() + 1)*dy + dx) = std::min(lookahead_delay, ctx->getDelayFromNS(delay));
setup(wire, src);
lookahead_delay = delay_lookahead.at(wire_type).at(src_type).at((ctx->getGridDimX() + 1)*dy + dx);
updates += lookahead_delay > ctx->getDelayFromNS(delay);
delay_lookahead.at(wire_type).at(src_type).at((ctx->getGridDimX() + 1)*dy + dx) = std::min(lookahead_delay, ctx->getDelayFromNS(delay));
WireScore score;
score.delay = 0;
score.cost = delay + cfg.get_base_cost(ctx, wire, uh, 1.0);
score.togo_cost = 0;
queue.push(QueuedWire(wire_to_idx.at(wire), score));
}
}
auto end_time = std::chrono::high_resolution_clock::now();
total_lookahead_calc_us += std::chrono::duration_cast<std::chrono::microseconds>(end_time - start_time).count();
if (updates == 0)
lookahead_learning_complete.at(src_type).insert(dst_type);
}
delay_t get_delay_lookahead(WireId src, WireId dst) {
auto src_type = ctx->getWireType(src);
auto dst_type = ctx->getWireType(dst);
auto bb = ctx->getRouteBoundingBox(src, dst);
auto dx = std::min(std::abs(bb.x1 - bb.x0), ctx->getGridDimX());
auto dy = std::min(std::abs(bb.y1 - bb.y0), ctx->getGridDimY());
if (delay_lookahead.count(src_type) != 0 && delay_lookahead.at(src_type).count(dst_type) != 0 && delay_lookahead.at(src_type).at(dst_type).at((ctx->getGridDimX() + 1)*dy + dx) < ctx->getDelayFromNS(500))
return delay_lookahead.at(src_type).at(dst_type).at((ctx->getGridDimX() + 1)*dy + dx);
std::unique_lock lock(delay_lookahead_mutex);
compute_delay_lookahead(src, dst);
return delay_lookahead.at(src_type).at(dst_type).at((ctx->getGridDimX() + 1)*dy + dx);
}
double curr_cong_weight, hist_cong_weight, estimate_weight;
struct ThreadContext
@ -387,7 +535,7 @@ struct Router2
source_uses = nd.wires.at(wd.w).second;
}
// FIXME: timing/wirelength balance?
delay_t est_delay = ctx->estimateDelay(bwd ? src_sink : wd.w, bwd ? wd.w : src_sink);
delay_t est_delay = get_delay_lookahead(bwd ? src_sink : wd.w, bwd ? wd.w : src_sink); //ctx->estimateDelay(bwd ? src_sink : wd.w, bwd ? wd.w : src_sink);
return (ctx->getDelayNS(est_delay) / (1 + source_uses * crit_weight)) + cfg.ipin_cost_adder;
}
@ -579,11 +727,11 @@ struct Router2
bool was_visited_fwd(int wire, float cost)
{
return flat_wires.at(wire).visited_fwd && flat_wires.at(wire).cost_fwd <= cost;
return flat_wires.at(wire).visited_fwd;
}
bool was_visited_bwd(int wire, float cost)
{
return flat_wires.at(wire).visited_bwd && flat_wires.at(wire).cost_bwd <= cost;
return flat_wires.at(wire).visited_bwd;
}
float get_arc_crit(NetInfo *net, store_index<PortRef> i)
@ -1493,6 +1641,7 @@ struct Router2
}
auto rend = std::chrono::high_resolution_clock::now();
log_info("Router2 time %.02fs\n", std::chrono::duration<float>(rend - rstart).count());
log_info(" Lookahead calculation time %.02fs\n", float(total_lookahead_calc_us) * 1e-6);
log_info("Running router1 to check that route is legal...\n");
@ -1527,7 +1676,7 @@ Router2Cfg::Router2Cfg(Context *ctx)
init_curr_cong_weight = ctx->setting<float>("router2/initCurrCongWeight", 0.5f);
hist_cong_weight = ctx->setting<float>("router2/histCongWeight", 1.0f);
curr_cong_mult = ctx->setting<float>("router2/currCongWeightMult", 2.0f);
estimate_weight = ctx->setting<float>("router2/estimateWeight", 1.25f);
estimate_weight = ctx->setting<float>("router2/estimateWeight", 0.75f);
}
perf_profile = ctx->setting<bool>("router2/perfProfile", false);
if (ctx->settings.count(ctx->id("router2/heatmap")))