caiyu/nextpnr
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

timing_opt: Fixes including single-move legality

Browse Source 
Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2018-12-02 12:23:18 +00:00
parent b51308708b
commit e1c74ad3db
2 changed files with 60 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
common/timing.cc
View File

@ -472,6 +472,8 @@ struct Timing
auto &nd = startdomain.second;
if (nd.false_startpoint)
continue;
if (startdomain.first.clock == async_clock)
continue;
const delay_t net_length_plus_one = nd.max_path_length + 1;
auto &net_min_remaining_budget = nd.min_remaining_budget;
if (nd.min_required.empty())
@ -555,6 +557,8 @@ struct Timing
const NetInfo *net = net_entry.first;
for (auto &startdomain : net_entry.second) {
auto &nd = startdomain.second;
if (startdomain.first.clock == async_clock)
continue;
if (nd.min_required.empty())
continue;
auto &nc = (*net_crit)[net->name];
@ -575,6 +579,8 @@ struct Timing
for (auto &net_entry : net_data) {
const NetInfo *net = net_entry.first;
for (auto &startdomain : net_entry.second) {
if (startdomain.first.clock == async_clock)
continue;
auto &nd = startdomain.second;
if (nd.min_required.empty())
continue;
@ -588,7 +594,7 @@ struct Timing
continue;
delay_t dmax = crit_path->at(ClockPair{startdomain.first, startdomain.first}).path_delay;
for (size_t i = 0; i < net->users.size(); i++) {
float criticality = 1.0 - ((nc.slack.at(i) - worst_slack.at(startdomain.first)) / dmax);
float criticality = 1.0f - (float(nc.slack.at(i) - worst_slack.at(startdomain.first)) / dmax);
nc.criticality.at(i) = std::max(nc.criticality.at(i), criticality);
}
nc.max_path_length = std::max(nc.max_path_length, nd.max_path_length);

69
common/timing_opt.cc
View File

@ -80,7 +80,7 @@ class TimingOptimiser
bool optimise() {
log_info("Running timing-driven placement optimisation...\n");
#if 1
timing_analysis(ctx, false, true, ctx->debug, false);
timing_analysis(ctx, false, true, false, false);
#endif
for (int i = 0; i < 20; i++) {
log_info(" Iteration %d...\n", i);
@ -90,7 +90,7 @@ class TimingOptimiser
for (auto &path : crit_paths)
optimise_path(path);
#if 1
timing_analysis(ctx, false, true, ctx->debug, false);
timing_analysis(ctx, false, true, false, false);
#endif
}
return true;
@ -146,8 +146,17 @@ class TimingOptimiser
if (dstBel == BelId())
continue;
if (ctx->estimateDelay(ctx->getBelPinWire(cell->bel, port.first),
ctx->getBelPinWire(dstBel, user.port)) > max_net_delay.at(std::make_pair(user.cell->name, user.port)))
ctx->getBelPinWire(dstBel, user.port)) > max_net_delay.at(std::make_pair(user.cell->name, user.port))) {
#if 0
if (ctx->debug) {
log_info(" est delay %.02fns exceeded maximum %.02fns\n", ctx->getDelayNS(ctx->estimateDelay(ctx->getBelPinWire(cell->bel, port.first),
ctx->getBelPinWire(dstBel, user.port))),
ctx->getDelayNS(max_net_delay.at(std::make_pair(user.cell->name, user.port))));
}
#endif
return false;
}
}
}
@ -193,6 +202,7 @@ class TimingOptimiser
BelId curr = cell->bel;
Loc curr_loc = ctx->getBelLocation(curr);
int found_count = 0;
cell_neighbour_bels[cell->name] = std::unordered_set<BelId>{};
for (int dy = -d; dy <= d; dy++) {
for (int dx = -d; dx <= d; dx++) {
// Go through all the Bels at this location
@ -207,7 +217,7 @@ class TimingOptimiser
CellInfo *bound = ctx->getBoundBelCell(bel);
if (bound == nullptr) {
free_bels_at_loc.push_back(bel);
} else if (bound->belStrength <= STRENGTH_WEAK) {
} else if (bound->belStrength <= STRENGTH_WEAK || bound->constr_parent != nullptr || !bound->constr_children.empty()) {
bound_bels_at_loc.push_back(bel);
}
}
@ -286,6 +296,7 @@ class TimingOptimiser
}
NPNR_ASSERT_FALSE("port user not found on net");
};
std::unordered_set<PortRef*> used_ports;
for (auto crit_net : crit_nets) {
std::deque<PortRef*> crit_path;
@ -318,6 +329,8 @@ class TimingOptimiser
continue;
size_t user_idx = port_user_index(cell, port.second);
float usr_crit = net_crit.at(pn->name).criticality.at(user_idx);
if (used_ports.count(&(pn->users.at(user_idx))))
continue;
if (usr_crit >= max_crit) {
max_crit = usr_crit;
crit_sink = std::make_pair(pn, user_idx);
@ -326,6 +339,7 @@ class TimingOptimiser
if (crit_sink.first != nullptr) {
crit_path.push_front(&(crit_sink.first->users.at(crit_sink.second)));
used_ports.insert(&(crit_sink.first->users.at(crit_sink.second)));
}
back_cursor = crit_sink.first;
}
@ -350,14 +364,19 @@ class TimingOptimiser
if (tpclass != TMG_COMB_OUTPUT)
continue;
auto &crits = net_crit.at(pn->name).criticality;
auto most_crit_usr = std::max_element(crits.begin(), crits.end());
if (*most_crit_usr >= max_crit) {
max_crit = *most_crit_usr;
crit_sink = std::make_pair(pn, std::distance(crits.begin(), most_crit_usr));
for (size_t i = 0; i < crits.size(); i++) {
if (used_ports.count(&(pn->users.at(i))))
continue;
if (crits.at(i) >= max_crit) {
max_crit = crits.at(i);
crit_sink = std::make_pair(pn, i);
}
}
}
if (crit_sink.first != nullptr) {
fwd_cursor = &(crit_sink.first->users.at(crit_sink.second));
used_ports.insert(&(crit_sink.first->users.at(crit_sink.second)));
} else {
fwd_cursor = nullptr;
}
@ -378,20 +397,30 @@ class TimingOptimiser
if (ctx->debug)
log_info("Optimising the following path: \n");
for (auto port : path) {
if (ctx->debug)
log_info(" %s.%s at %s\n", port->cell->name.c_str(ctx), port->port.c_str(ctx), ctx->getBelName(port->cell->bel).c_str(ctx));
if (ctx->debug) {
float crit = 0;
NetInfo *pn = port->cell->ports.at(port->port).net;
if (net_crit.count(pn->name) && !net_crit.at(pn->name).criticality.empty())
for (size_t i = 0; i < pn->users.size(); i++)
if (pn->users.at(i).cell == port->cell && pn->users.at(i).port == port->port)
crit = net_crit.at(pn->name).criticality.at(i);
log_info(" %s.%s at %s crit %0.02f\n", port->cell->name.c_str(ctx), port->port.c_str(ctx), ctx->getBelName(port->cell->bel).c_str(ctx), crit);
}
if (std::find(path_cells.begin(), path_cells.end(), port->cell->name) != path_cells.end())
continue;
if (port->cell->belStrength > STRENGTH_WEAK || !cfg.cellTypes.count(port->cell->type))
if (port->cell->belStrength > STRENGTH_WEAK || !cfg.cellTypes.count(port->cell->type) || port->cell->constr_parent != nullptr || !port->cell->constr_children.empty())
continue;
if (ctx->debug)
log_info(" can move\n");
path_cells.push_back(port->cell->name);
}
if (path_cells.empty())
if (path_cells.size() < 3) {
log_info("Too few moveable cells; skipping path\n");
log_break();
return;
}
IdString last_cell;
const int d = 3; // FIXME: how to best determine d
for (auto cell : path_cells) {
@ -420,9 +449,17 @@ class TimingOptimiser
std::unordered_set<std::pair<int, BelId>> to_visit;
for (auto startbel : cell_neighbour_bels[path_cells.front()]) {
auto entry = std::make_pair(0, startbel);
visit.push(entry);
cumul_costs[path_cells.front()][startbel] = 0;
// Swap for legality check
CellInfo *cell = ctx->cells.at(path_cells.front()).get();
BelId origBel = cell_swap_bel(cell, startbel);
std::vector<std::pair<CellInfo*,BelId>> move{std::make_pair(cell, origBel)};
if (acceptable_move(move)) {
auto entry = std::make_pair(0, startbel);
visit.push(entry);
cumul_costs[path_cells.front()][startbel] = 0;
}
// Swap back
cell_swap_bel(cell, origBel);
}
while(!visit.empty()) {