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timing_opt: Neighbour related fixes

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2018-12-02 16:34:58 +00:00
parent f53dc8d3c9
commit 745960fa85
1 changed files with 23 additions and 8 deletions
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31
common/timing_opt.cc
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@ -86,11 +86,11 @@ class TimingOptimiser
#if 1 #if 1
timing_analysis(ctx, false, true, false, false); timing_analysis(ctx, false, true, false, false);
#endif #endif
for (int i = 0; i < 20; i++) { for (int i = 0; i < 100; i++) {
log_info(" Iteration %d...\n", i); log_info(" Iteration %d...\n", i);
get_criticalities(ctx, &net_crit); get_criticalities(ctx, &net_crit);
setup_delay_limits(); setup_delay_limits();
auto crit_paths = find_crit_paths(0.98, 1000); auto crit_paths = find_crit_paths(0.98, 50000);
for (auto &path : crit_paths) for (auto &path : crit_paths)
optimise_path(path); optimise_path(path);
#if 1 #if 1
@ -122,7 +122,7 @@ class TimingOptimiser
delay_t net_delay = ctx->getNetinfoRouteDelay(ni, usr); delay_t net_delay = ctx->getNetinfoRouteDelay(ni, usr);
if (nc.max_path_length != 0) { if (nc.max_path_length != 0) {
max_net_delay[std::make_pair(usr.cell->name, usr.port)] = max_net_delay[std::make_pair(usr.cell->name, usr.port)] =
net_delay + ((nc.slack.at(i) - nc.cd_worst_slack) / nc.max_path_length); net_delay + ((nc.slack.at(i) - nc.cd_worst_slack) / 10);
} }
} }
} }
@ -168,6 +168,8 @@ class TimingOptimiser
BelId cell_swap_bel(CellInfo *cell, BelId newBel) BelId cell_swap_bel(CellInfo *cell, BelId newBel)
{ {
BelId oldBel = cell->bel; BelId oldBel = cell->bel;
if (oldBel == newBel)
return oldBel;
CellInfo *other_cell = ctx->getBoundBelCell(newBel); CellInfo *other_cell = ctx->getBoundBelCell(newBel);
NPNR_ASSERT(other_cell == nullptr || other_cell->belStrength <= STRENGTH_WEAK); NPNR_ASSERT(other_cell == nullptr || other_cell->belStrength <= STRENGTH_WEAK);
ctx->unbindBel(oldBel); ctx->unbindBel(oldBel);
@ -221,14 +223,14 @@ class TimingOptimiser
CellInfo *bound = ctx->getBoundBelCell(bel); CellInfo *bound = ctx->getBoundBelCell(bel);
if (bound == nullptr) { if (bound == nullptr) {
free_bels_at_loc.push_back(bel); free_bels_at_loc.push_back(bel);
} else if (bound->belStrength <= STRENGTH_WEAK || bound->constr_parent != nullptr || } else if (bound->belStrength <= STRENGTH_WEAK && bound->constr_parent == nullptr &&
!bound->constr_children.empty()) { bound->constr_children.empty()) {
bound_bels_at_loc.push_back(bel); bound_bels_at_loc.push_back(bel);
} }
} }
BelId candidate; BelId candidate;
while (!free_bels_at_loc.empty() && !bound_bels_at_loc.empty()) { while (!free_bels_at_loc.empty() || !bound_bels_at_loc.empty()) {
BelId try_bel; BelId try_bel;
if (!free_bels_at_loc.empty()) { if (!free_bels_at_loc.empty()) {
int try_idx = ctx->rng(int(free_bels_at_loc.size())); int try_idx = ctx->rng(int(free_bels_at_loc.size()));
@ -244,7 +246,7 @@ class TimingOptimiser
// edges in the graph), or if allow_swap is true to deal with cases where overlap means few // edges in the graph), or if allow_swap is true to deal with cases where overlap means few
// neighbours are identified // neighbours are identified
if (bel_candidate_cells.at(try_bel).size() > 1 || if (bel_candidate_cells.at(try_bel).size() > 1 ||
(bel_candidate_cells.at(try_bel).size() == 0 || (bel_candidate_cells.at(try_bel).size() == 1 &&
*(bel_candidate_cells.at(try_bel).begin()) != prev_cell)) *(bel_candidate_cells.at(try_bel).begin()) != prev_cell))
continue; continue;
} }
@ -304,6 +306,10 @@ class TimingOptimiser
std::unordered_set<PortRef *> used_ports; std::unordered_set<PortRef *> used_ports;
for (auto crit_net : crit_nets) { for (auto crit_net : crit_nets) {
if (used_ports.count(&(crit_net.first->users.at(crit_net.second))))
continue;
std::deque<PortRef *> crit_path; std::deque<PortRef *> crit_path;
// FIXME: This will fail badly on combinational loops // FIXME: This will fail badly on combinational loops
@ -460,13 +466,22 @@ class TimingOptimiser
} }
IdString last_cell; IdString last_cell;
const int d = 3; // FIXME: how to best determine d const int d = 5; // FIXME: how to best determine d
for (auto cell : path_cells) { for (auto cell : path_cells) {
// FIXME: when should we allow swapping due to a lack of candidates // FIXME: when should we allow swapping due to a lack of candidates
find_neighbours(ctx->cells[cell].get(), last_cell, d, false); find_neighbours(ctx->cells[cell].get(), last_cell, d, false);
last_cell = cell; last_cell = cell;
} }
if (ctx->debug) {
for (auto cell : path_cells) {
log_info("Candidate neighbours for %s (%s):\n", cell.c_str(ctx), ctx->getBelName(ctx->cells[cell]->bel).c_str(ctx));
for (auto neigh : cell_neighbour_bels.at(cell)) {
log_info(" %s\n", ctx->getBelName(neigh).c_str(ctx));
}
}
}
// Actual BFS path optimisation algorithm // Actual BFS path optimisation algorithm
std::unordered_map<IdString, std::unordered_map<BelId, delay_t>> cumul_costs; std::unordered_map<IdString, std::unordered_map<BelId, delay_t>> cumul_costs;
std::unordered_map<std::pair<IdString, BelId>, std::pair<IdString, BelId>> backtrace; std::unordered_map<std::pair<IdString, BelId>, std::pair<IdString, BelId>> backtrace;