diff options
Diffstat (limited to 'common')
| -rw-r--r-- | common/nextpnr.h | 1 | ||||
| -rw-r--r-- | common/place_common.cc | 6 | ||||
| -rw-r--r-- | common/placer1.cc | 11 | ||||
| -rw-r--r-- | common/router1.cc | 4 | ||||
| -rw-r--r-- | common/timing.cc | 177 | ||||
| -rw-r--r-- | common/timing.h | 8 |
6 files changed, 162 insertions, 45 deletions
diff --git a/common/nextpnr.h b/common/nextpnr.h index 908b8266..38a313fd 100644 --- a/common/nextpnr.h +++ b/common/nextpnr.h @@ -475,6 +475,7 @@ struct Context : Arch, DeterministicRNG bool force = false; bool timing_driven = true; float target_freq = 12e6; + bool user_freq = false; Context(ArchArgs args) : Arch(args) {} diff --git a/common/place_common.cc b/common/place_common.cc index 5673c847..9fba90f9 100644 --- a/common/place_common.cc +++ b/common/place_common.cc @@ -40,7 +40,7 @@ wirelen_t get_net_metric(const Context *ctx, const NetInfo *net, MetricType type WireId drv_wire = ctx->getBelPinWire(driver_cell->bel, ctx->portPinFromId(net->driver.port)); if (driver_gb) return 0; - float worst_slack = 1000; + delay_t worst_slack = std::numeric_limits<delay_t>::max(); int xmin = driver_loc.x, xmax = driver_loc.x, ymin = driver_loc.y, ymax = driver_loc.y; for (auto load : net->users) { if (load.cell == nullptr) @@ -51,7 +51,7 @@ wirelen_t get_net_metric(const Context *ctx, const NetInfo *net, MetricType type if (ctx->timing_driven && type == MetricType::COST) { WireId user_wire = ctx->getBelPinWire(load_cell->bel, ctx->portPinFromId(load.port)); delay_t raw_wl = ctx->estimateDelay(drv_wire, user_wire); - float slack = ctx->getDelayNS(load.budget) - ctx->getDelayNS(raw_wl); + auto slack = load.budget - raw_wl; if (slack < 0) tns += slack; worst_slack = std::min(slack, worst_slack); @@ -67,7 +67,7 @@ wirelen_t get_net_metric(const Context *ctx, const NetInfo *net, MetricType type ymax = std::max(ymax, load_loc.y); } if (ctx->timing_driven && type == MetricType::COST) { - wirelength = wirelen_t((((ymax - ymin) + (xmax - xmin)) * std::min(5.0, (1.0 + std::exp(-worst_slack / 5))))); + wirelength = wirelen_t((((ymax - ymin) + (xmax - xmin)) * std::min(5.0, (1.0 + std::exp(-ctx->getDelayNS(worst_slack) / 5))))); } else { wirelength = wirelen_t((ymax - ymin) + (xmax - xmin)); } diff --git a/common/placer1.cc b/common/placer1.cc index ee7225b5..c677a22a 100644 --- a/common/placer1.cc +++ b/common/placer1.cc @@ -152,6 +152,7 @@ class SAPlacer } int n_no_progress = 0; + wirelen_t min_metric = curr_metric; double avg_metric = curr_metric; temp = 10000; @@ -177,6 +178,11 @@ class SAPlacer } } + if (curr_metric < min_metric) { + min_metric = curr_metric; + improved = true; + } + // Heuristic to improve placement on the 8k if (improved) n_no_progress = 0; @@ -230,6 +236,8 @@ class SAPlacer diameter *= post_legalise_dia_scale; ctx->shuffle(autoplaced); assign_budget(ctx); + } else { + assign_budget(ctx, true /* quiet */); } // Recalculate total metric entirely to avoid rounding errors @@ -264,6 +272,7 @@ class SAPlacer } } } + timing_analysis(ctx, true /* print_fmax */); ctx->unlock(); return true; } @@ -379,8 +388,6 @@ class SAPlacer // SA acceptance criterea if (delta < 0 || (temp > 1e-6 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) { n_accept++; - if (delta < 2) - improved = true; } else { if (other != IdString()) ctx->unbindBel(oldBel); diff --git a/common/router1.cc b/common/router1.cc index 4ef7df64..0bd257fd 100644 --- a/common/router1.cc +++ b/common/router1.cc @@ -22,6 +22,7 @@ #include "log.h" #include "router1.h" +#include "timing.h" namespace { @@ -615,6 +616,8 @@ bool router1(Context *ctx) if (ctx->verbose || iterCnt == 1) log_info("routing queue contains %d jobs.\n", int(jobQueue.size())); + assign_budget(ctx, true /* quiet */); + bool printNets = ctx->verbose && (jobQueue.size() < 10); while (!jobQueue.empty()) { @@ -811,6 +814,7 @@ bool router1(Context *ctx) #ifndef NDEBUG ctx->check(); #endif + timing_analysis(ctx, true /* print_fmax */, true /* print_path */); ctx->unlock(); return true; } catch (log_execution_error_exception) { diff --git a/common/timing.cc b/common/timing.cc index d91dea20..78a56ba9 100644 --- a/common/timing.cc +++ b/common/timing.cc @@ -22,99 +22,200 @@ #include <unordered_map> #include <utility> #include "log.h" +#include "util.h" NEXTPNR_NAMESPACE_BEGIN -static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack); +typedef std::list<const PortRef *> PortRefList; + +static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, bool update, delay_t &min_slack, + PortRefList *current_path, PortRefList *crit_path); // Follow a path, returning budget to annotate -static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, delay_t slack) +static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, delay_t slack, bool update, + delay_t &min_slack, PortRefList *current_path, PortRefList *crit_path) { delay_t value; if (ctx->getPortClock(user.cell, user.port) != IdString()) { // At the end of a timing path (arguably, should check setup time // here too) value = slack / path_length; + if (slack < min_slack) { + min_slack = slack; + if (crit_path) + *crit_path = *current_path; + } } else { // Default to the path ending here, if no further paths found value = slack / path_length; // Follow outputs of the user for (auto port : user.cell->ports) { if (port.second.type == PORT_OUT) { - delay_t comb_delay; + DelayInfo comb_delay; // Look up delay through this path bool is_path = ctx->getCellDelay(user.cell, user.port, port.first, comb_delay); if (is_path) { NetInfo *net = port.second.net; if (net) { - delay_t path_budget = follow_net(ctx, net, path_length, slack - comb_delay); + delay_t path_budget = follow_net(ctx, net, path_length, slack - comb_delay.maxDelay(), update, min_slack, + current_path, crit_path); value = std::min(value, path_budget); } } } } } - - if (value < user.budget) { - user.budget = value; - } return value; } -static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack) +static delay_t follow_net(Context *ctx, NetInfo *net, int path_length, delay_t slack, bool update, delay_t &min_slack, + PortRefList *current_path, PortRefList *crit_path) { delay_t net_budget = slack / (path_length + 1); - for (auto &usr : net->users) { - net_budget = std::min(net_budget, follow_user_port(ctx, usr, path_length + 1, slack)); + for (unsigned i = 0; i < net->users.size(); ++i) { + auto &usr = net->users[i]; + if (crit_path) + current_path->push_back(&usr); + // If budget override is less than existing budget, then do not increment path length + int pl = path_length + 1; + auto budget = ctx->getBudgetOverride(net, i, net_budget); + if (budget < net_budget) { + net_budget = budget; + pl = std::max(1, path_length); + } + auto delay = ctx->getNetinfoRouteDelay(net, i); + net_budget = std::min( + net_budget, follow_user_port(ctx, usr, pl, slack - delay, update, min_slack, current_path, crit_path)); + if (update) + usr.budget = std::min(usr.budget, delay + net_budget); + if (crit_path) + current_path->pop_back(); } return net_budget; } -void assign_budget(Context *ctx) +static delay_t walk_paths(Context *ctx, bool update, PortRefList *crit_path) { - log_break(); - log_info("Annotating ports with timing budgets\n"); - // Clear delays to a very high value first delay_t default_slack = delay_t(1.0e12 / ctx->target_freq); - for (auto &net : ctx->nets) { - for (auto &usr : net.second->users) { - usr.budget = default_slack; - } - } - // Go through all clocked drivers and set up paths + delay_t min_slack = default_slack; + + PortRefList current_path; + + // Go through all clocked drivers and distribute the available path + // slack evenly into the budget of every sink on the path --- + // record this value into the UpdateMap for (auto &cell : ctx->cells) { for (auto port : cell.second->ports) { if (port.second.type == PORT_OUT) { IdString clock_domain = ctx->getPortClock(cell.second.get(), port.first); if (clock_domain != IdString()) { - delay_t slack = delay_t(1.0e12 / ctx->target_freq); // TODO: clock constraints - delay_t clkToQ; + delay_t slack = default_slack; // TODO: clock constraints + DelayInfo clkToQ; if (ctx->getCellDelay(cell.second.get(), clock_domain, port.first, clkToQ)) - slack -= clkToQ; + slack -= clkToQ.maxDelay(); if (port.second.net) - follow_net(ctx, port.second.net, 0, slack); + follow_net(ctx, port.second.net, 0, slack, update, min_slack, ¤t_path, crit_path); } } } } - // Post-allocation check + return min_slack; +} + +void assign_budget(Context *ctx, bool quiet) +{ + if (!quiet) { + log_break(); + log_info("Annotating ports with timing budgets\n"); + } + + // Clear delays to a very high value first + delay_t default_slack = delay_t(1.0e12 / ctx->target_freq); for (auto &net : ctx->nets) { - for (auto user : net.second->users) { - if (user.budget < 0) - log_warning("port %s.%s, connected to net '%s', has negative " - "timing budget of %fns\n", - user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx), - ctx->getDelayNS(user.budget)); - if (ctx->verbose) - log_info("port %s.%s, connected to net '%s', has " - "timing budget of %fns\n", - user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx), - ctx->getDelayNS(user.budget)); + for (auto &usr : net.second->users) { + usr.budget = default_slack; + } + } + + delay_t min_slack = walk_paths(ctx, true, nullptr); + + if (!quiet || ctx->verbose) { + for (auto &net : ctx->nets) { + for (auto &user : net.second->users) { + // Post-update check + if (ctx->user_freq && user.budget < 0) + log_warning("port %s.%s, connected to net '%s', has negative " + "timing budget of %fns\n", + user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx), + ctx->getDelayNS(user.budget)); + else if (ctx->verbose) + log_info("port %s.%s, connected to net '%s', has " + "timing budget of %fns\n", + user.cell->name.c_str(ctx), user.port.c_str(ctx), net.first.c_str(ctx), + ctx->getDelayNS(user.budget)); + } } } - log_info("Checksum: 0x%08x\n", ctx->checksum()); + // If user has not specified a frequency, dynamically adjust the target + // frequency to be the current maximum + if (!ctx->user_freq) { + ctx->target_freq = 1e12 / (default_slack - min_slack); + if (ctx->verbose) + log_info("minimum slack for this assign = %d, target Fmax for next update = %.2f MHz\n", min_slack, + ctx->target_freq / 1e6); + } + + if (!quiet) + log_info("Checksum: 0x%08x\n", ctx->checksum()); +} + +delay_t timing_analysis(Context *ctx, bool print_fmax, bool print_path) +{ + delay_t default_slack = delay_t(1.0e12 / ctx->target_freq); + PortRefList crit_path; + delay_t min_slack = walk_paths(ctx, false, &crit_path); + if (print_path) { + delay_t total = 0; + log_break(); + log_info("Critical path report:\n"); + log_info("curr total\n"); + auto &front = crit_path.front(); + auto &front_port = front->cell->ports.at(front->port); + auto &front_driver = front_port.net->driver; + auto last_port = ctx->getPortClock(front_driver.cell, front_driver.port); + for (auto sink : crit_path) { + auto sink_cell = sink->cell; + auto &port = sink_cell->ports.at(sink->port); + auto net = port.net; + unsigned i = 0; + for (auto &usr : net->users) + if (&usr == sink) + break; + else + ++i; + auto &driver = net->driver; + auto driver_cell = driver.cell; + DelayInfo comb_delay; + ctx->getCellDelay(sink_cell, last_port, driver.port, comb_delay); + total += comb_delay.maxDelay(); + log_info("%4d %4d Source %s.%s\n", comb_delay.maxDelay(), total, driver_cell->name.c_str(ctx), + driver.port.c_str(ctx)); + auto net_delay = ctx->getNetinfoRouteDelay(net, i); + total += net_delay; + auto driver_loc = ctx->getBelLocation(driver_cell->bel); + auto sink_loc = ctx->getBelLocation(sink_cell->bel); + log_info("%4d %4d Net %s budget %d (%d,%d) -> (%d,%d)\n", net_delay, total, net->name.c_str(ctx), + sink->budget, driver_loc.x, driver_loc.y, sink_loc.x, sink_loc.y); + log_info(" Sink %s.%s\n", sink_cell->name.c_str(ctx), sink->port.c_str(ctx)); + last_port = sink->port; + } + log_break(); + } + if (print_fmax) + log_info("estimated Fmax = %.2f MHz\n", 1e6 / (default_slack - min_slack)); + return min_slack; } NEXTPNR_NAMESPACE_END diff --git a/common/timing.h b/common/timing.h index 025e4a76..d0159d5c 100644 --- a/common/timing.h +++ b/common/timing.h @@ -24,8 +24,12 @@ NEXTPNR_NAMESPACE_BEGIN -// Assign "budget" values for all user ports in the design -void assign_budget(Context *ctx); +// Evenly redistribute the total path slack amongst all sinks on each path +void assign_budget(Context *ctx, bool quiet = false); + +// Perform timing analysis and return the minimum path slack, +// optionally, print out the fmax and critical path +delay_t timing_analysis(Context *ctx, bool print_fmax = false, bool print_path = false); NEXTPNR_NAMESPACE_END |