diff options
Diffstat (limited to 'common/timing.cc')
| -rw-r--r-- | common/timing.cc | 150 |
1 files changed, 148 insertions, 2 deletions
diff --git a/common/timing.cc b/common/timing.cc index 88ab14c2..55d3a46f 100644 --- a/common/timing.cc +++ b/common/timing.cc @@ -85,7 +85,16 @@ struct CriticalPath delay_t path_period; }; +// Data for the timing optimisation algorithm +struct NetCriticalityInfo +{ + // One each per user + std::vector<delay_t> slack; + std::vector<float> criticality; +}; + typedef std::unordered_map<ClockPair, CriticalPath> CriticalPathMap; +typedef std::unordered_map<IdString, NetCriticalityInfo> NetCriticalityMap; struct Timing { @@ -96,6 +105,7 @@ struct Timing CriticalPathMap *crit_path; DelayFrequency *slack_histogram; IdString async_clock; + NetCriticalityMap *net_crit; struct TimingData { @@ -105,13 +115,15 @@ struct Timing unsigned max_path_length = 0; delay_t min_remaining_budget; bool false_startpoint = false; + std::vector<delay_t> min_required; std::unordered_map<ClockEvent, delay_t> arrival_time; }; Timing(Context *ctx, bool net_delays, bool update, CriticalPathMap *crit_path = nullptr, - DelayFrequency *slack_histogram = nullptr) + DelayFrequency *slack_histogram = nullptr, NetCriticalityMap *net_crit = nullptr) : ctx(ctx), net_delays(net_delays), update(update), min_slack(1.0e12 / ctx->target_freq), - crit_path(crit_path), slack_histogram(slack_histogram), async_clock(ctx->id("$async$")) + crit_path(crit_path), slack_histogram(slack_histogram), net_crit(net_crit), + async_clock(ctx->id("$async$")) { } @@ -454,6 +466,140 @@ struct Timing std::reverse(cp_ports.begin(), cp_ports.end()); } } + + if (net_crit) { + NPNR_ASSERT(crit_path); + // Go through in reverse topographical order to set required times + for (auto net : boost::adaptors::reverse(topographical_order)) { + if (!net_data.count(net)) + continue; + auto &nd_map = net_data.at(net); + for (auto &startdomain : nd_map) { + auto &nd = startdomain.second; + if (nd.false_startpoint) + 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()) + nd.min_required.resize(net->users.size(), std::numeric_limits<delay_t>::max()); + delay_t net_min_required = std::numeric_limits<delay_t>::max(); + for (size_t i = 0; i < net->users.size(); i++) { + auto &usr = net->users.at(i); + auto net_delay = ctx->getNetinfoRouteDelay(net, usr); + int port_clocks; + TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, usr.port, port_clocks); + if (portClass == TMG_REGISTER_INPUT || portClass == TMG_ENDPOINT) { + auto process_endpoint = [&](IdString clksig, ClockEdge edge, delay_t setup) { + delay_t period; + // Set default period + if (edge == startdomain.first.edge) { + period = clk_period; + } else { + period = clk_period / 2; + } + if (clksig != async_clock) { + if (ctx->nets.at(clksig)->clkconstr) { + if (edge == startdomain.first.edge) { + // same edge + period = ctx->nets.at(clksig)->clkconstr->period.minDelay(); + } else if (edge == RISING_EDGE) { + // falling -> rising + period = ctx->nets.at(clksig)->clkconstr->low.minDelay(); + } else if (edge == FALLING_EDGE) { + // rising -> falling + period = ctx->nets.at(clksig)->clkconstr->high.minDelay(); + } + } + } + nd.min_required.at(i) = std::min(period - setup, nd.min_required.at(i)); + }; + if (portClass == TMG_REGISTER_INPUT) { + for (int j = 0; j < port_clocks; j++) { + TimingClockingInfo clkInfo = ctx->getPortClockingInfo(usr.cell, usr.port, j); + const NetInfo *clknet = get_net_or_empty(usr.cell, clkInfo.clock_port); + IdString clksig = clknet ? clknet->name : async_clock; + process_endpoint(clksig, clknet ? clkInfo.edge : RISING_EDGE, + clkInfo.setup.maxDelay()); + } + } else { + process_endpoint(async_clock, RISING_EDGE, 0); + } + } + net_min_required = std::min(net_min_required, nd.min_required.at(i) - net_delay); + } + PortRef &drv = net->driver; + if (drv.cell == nullptr) + continue; + for (const auto &port : drv.cell->ports) { + if (port.second.type != PORT_IN || !port.second.net) + continue; + DelayInfo comb_delay; + bool is_path = ctx->getCellDelay(drv.cell, port.first, drv.port, comb_delay); + if (!is_path) + continue; + NetInfo *sink_net = port.second.net; + if (net_data.count(sink_net) && net_data.at(sink_net).count(startdomain.first)) { + auto &sink_nd = net_data.at(sink_net).at(startdomain.first); + if (sink_nd.min_required.empty()) + sink_nd.min_required.resize(sink_net->users.size(), + std::numeric_limits<delay_t>::max()); + for (size_t i = 0; i < sink_net->users.size(); i++) { + auto &user = sink_net->users.at(i); + if (user.cell == drv.cell && user.port == port.first) { + sink_nd.min_required.at(i) = net_min_required - comb_delay.maxDelay(); + break; + } + } + } + } + } + } + std::unordered_map<ClockEvent, delay_t> worst_slack; + + // Assign slack values + for (auto &net_entry : net_data) { + const NetInfo *net = net_entry.first; + for (auto &startdomain : net_entry.second) { + auto &nd = startdomain.second; + if (nd.min_required.empty()) + continue; + auto &nc = (*net_crit)[net->name]; + if (nc.slack.empty()) + nc.slack.resize(net->users.size(), std::numeric_limits<delay_t>::max()); + for (size_t i = 0; i < net->users.size(); i++) { + delay_t slack = nd.min_required.at(i) - + (nd.max_arrival + ctx->getNetinfoRouteDelay(net, net->users.at(i))); + if (worst_slack.count(startdomain.first)) + worst_slack.at(startdomain.first) = std::min(worst_slack.at(startdomain.first), slack); + else + worst_slack[startdomain.first] = slack; + nc.slack.at(i) = std::min(nc.slack.at(i), slack); + } + } + } + // Assign criticality values + for (auto &net_entry : net_data) { + const NetInfo *net = net_entry.first; + for (auto &startdomain : net_entry.second) { + auto &nd = startdomain.second; + if (nd.min_required.empty()) + continue; + auto &nc = (*net_crit)[net->name]; + if (nc.slack.empty()) + continue; + if (nc.criticality.empty()) + nc.criticality.resize(net->users.size(), 0); + // Only consider intra-clock paths for criticality + if (!crit_path->count(ClockPair{startdomain.first, startdomain.first})) + 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); + nc.criticality.at(i) = std::max(nc.criticality.at(i), criticality); + } + } + } + } return min_slack; } |