diff options
Diffstat (limited to 'common')
| -rw-r--r-- | common/nextpnr.cc | 17 | ||||
| -rw-r--r-- | common/nextpnr.h | 13 | ||||
| -rw-r--r-- | common/place_common.cc | 15 | ||||
| -rw-r--r-- | common/placer1.cc | 12 | ||||
| -rw-r--r-- | common/router1.cc | 17 | ||||
| -rw-r--r-- | common/timing.cc | 162 | ||||
| -rw-r--r-- | common/timing.h | 8 |
7 files changed, 177 insertions, 67 deletions
diff --git a/common/nextpnr.cc b/common/nextpnr.cc index cf1b5982..dbea26d8 100644 --- a/common/nextpnr.cc +++ b/common/nextpnr.cc @@ -51,7 +51,7 @@ void IdString::initialize_add(const BaseCtx *ctx, const char *s, int idx) ctx->idstring_idx_to_str->push_back(&insert_rc.first->first); } -WireId Context::getNetinfoSourceWire(NetInfo *net_info) const +WireId Context::getNetinfoSourceWire(const NetInfo *net_info) const { if (net_info->driver.cell == nullptr) return WireId(); @@ -70,9 +70,8 @@ WireId Context::getNetinfoSourceWire(NetInfo *net_info) const return getBelPinWire(src_bel, portPinFromId(driver_port)); } -WireId Context::getNetinfoSinkWire(NetInfo *net_info, int user_idx) const +WireId Context::getNetinfoSinkWire(const NetInfo *net_info, const PortRef &user_info) const { - auto &user_info = net_info->users[user_idx]; auto dst_bel = user_info.cell->bel; if (dst_bel == BelId()) @@ -88,12 +87,14 @@ WireId Context::getNetinfoSinkWire(NetInfo *net_info, int user_idx) const return getBelPinWire(dst_bel, portPinFromId(user_port)); } -delay_t Context::getNetinfoRouteDelay(NetInfo *net_info, int user_idx) const +delay_t Context::getNetinfoRouteDelay(const NetInfo *net_info, const PortRef &user_info) const { WireId src_wire = getNetinfoSourceWire(net_info); if (src_wire == WireId()) return 0; - WireId cursor = getNetinfoSinkWire(net_info, user_idx); + + WireId dst_wire = getNetinfoSinkWire(net_info, user_info); + WireId cursor = dst_wire; delay_t delay = 0; while (cursor != WireId() && cursor != src_wire) { @@ -107,11 +108,9 @@ delay_t Context::getNetinfoRouteDelay(NetInfo *net_info, int user_idx) const } if (cursor == src_wire) - delay += getWireDelay(src_wire).maxDelay(); - else - delay += estimateDelay(src_wire, cursor); + return delay + getWireDelay(src_wire).maxDelay(); - return delay; + return predictDelay(net_info, user_info); } static uint32_t xorshift32(uint32_t x) diff --git a/common/nextpnr.h b/common/nextpnr.h index 908b8266..f01173e6 100644 --- a/common/nextpnr.h +++ b/common/nextpnr.h @@ -205,10 +205,7 @@ struct DecalXY DecalId decal; float x = 0, y = 0; - bool operator==(const DecalXY &other) const - { - return (decal == other.decal && x == other.x && y == other.y); - } + bool operator==(const DecalXY &other) const { return (decal == other.decal && x == other.x && y == other.y); } }; struct BelPin @@ -475,14 +472,16 @@ struct Context : Arch, DeterministicRNG bool force = false; bool timing_driven = true; float target_freq = 12e6; + bool user_freq = false; + int slack_redist_iter = 0; Context(ArchArgs args) : Arch(args) {} // -------------------------------------------------------------- - WireId getNetinfoSourceWire(NetInfo *net_info) const; - WireId getNetinfoSinkWire(NetInfo *net_info, int user_idx) const; - delay_t getNetinfoRouteDelay(NetInfo *net_info, int user_idx) const; + WireId getNetinfoSourceWire(const NetInfo *net_info) const; + WireId getNetinfoSinkWire(const NetInfo *net_info, const PortRef &sink) const; + delay_t getNetinfoRouteDelay(const NetInfo *net_info, const PortRef &sink) const; // provided by router1.cc bool getActualRouteDelay(WireId src_wire, WireId dst_wire, delay_t &delay); diff --git a/common/place_common.cc b/common/place_common.cc index 5673c847..fd38429f 100644 --- a/common/place_common.cc +++ b/common/place_common.cc @@ -37,10 +37,10 @@ wirelen_t get_net_metric(const Context *ctx, const NetInfo *net, MetricType type return 0; driver_gb = ctx->getBelGlobalBuf(driver_cell->bel); driver_loc = ctx->getBelLocation(driver_cell->bel); - WireId drv_wire = ctx->getBelPinWire(driver_cell->bel, ctx->portPinFromId(net->driver.port)); if (driver_gb) return 0; - float worst_slack = 1000; + delay_t negative_slack = 0; + 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) @@ -49,11 +49,10 @@ wirelen_t get_net_metric(const Context *ctx, const NetInfo *net, MetricType type if (load_cell->bel == BelId()) continue; 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); + delay_t net_delay = ctx->predictDelay(net, load); + auto slack = load.budget - net_delay; if (slack < 0) - tns += slack; + negative_slack += slack; worst_slack = std::min(slack, worst_slack); } @@ -67,11 +66,13 @@ 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)); } + tns += ctx->getDelayNS(negative_slack); return wirelength; } diff --git a/common/placer1.cc b/common/placer1.cc index ee7225b5..68db9650 100644 --- a/common/placer1.cc +++ b/common/placer1.cc @@ -138,6 +138,7 @@ class SAPlacer if ((placed_cells - constr_placed_cells) % 500 != 0) log_info(" initial placement placed %d/%d cells\n", int(placed_cells - constr_placed_cells), int(autoplaced.size())); + assign_budget(ctx); ctx->yield(); log_info("Running simulated annealing placer.\n"); @@ -152,6 +153,7 @@ class SAPlacer } int n_no_progress = 0; + wirelen_t min_metric = curr_metric; double avg_metric = curr_metric; temp = 10000; @@ -177,6 +179,11 @@ 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 +237,8 @@ class SAPlacer diameter *= post_legalise_dia_scale; ctx->shuffle(autoplaced); assign_budget(ctx); + } else if (ctx->slack_redist_iter > 0 && iter % ctx->slack_redist_iter == 0) { + assign_budget(ctx, true /* quiet */); } // Recalculate total metric entirely to avoid rounding errors @@ -264,6 +273,7 @@ class SAPlacer } } } + timing_analysis(ctx, true /* print_fmax */); ctx->unlock(); return true; } @@ -379,8 +389,6 @@ 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..d35a7621 100644 --- a/common/router1.cc +++ b/common/router1.cc @@ -22,6 +22,7 @@ #include "log.h" #include "router1.h" +#include "timing.h" namespace { @@ -297,7 +298,7 @@ struct Router src_wires[src_wire] = ctx->getWireDelay(src_wire).maxDelay(); for (int user_idx = 0; user_idx < int(net_info->users.size()); user_idx++) { - auto dst_wire = ctx->getNetinfoSinkWire(net_info, user_idx); + auto dst_wire = ctx->getNetinfoSinkWire(net_info, net_info->users[user_idx]); if (dst_wire == WireId()) log_error("No wire found for port %s on destination cell %s.\n", @@ -351,7 +352,7 @@ struct Router log(" Route to: %s.%s.\n", net_info->users[user_idx].cell->name.c_str(ctx), net_info->users[user_idx].port.c_str(ctx)); - auto dst_wire = ctx->getNetinfoSinkWire(net_info, user_idx); + auto dst_wire = ctx->getNetinfoSinkWire(net_info, net_info->users[user_idx]); if (dst_wire == WireId()) log_error("No wire found for port %s on destination cell %s.\n", @@ -482,7 +483,7 @@ void addFullNetRouteJob(Context *ctx, IdString net_name, std::unordered_map<IdSt if (net_cache[user_idx]) continue; - auto dst_wire = ctx->getNetinfoSinkWire(net_info, user_idx); + auto dst_wire = ctx->getNetinfoSinkWire(net_info, net_info->users[user_idx]); if (dst_wire == WireId()) log_error("No wire found for port %s on destination cell %s.\n", net_info->users[user_idx].port.c_str(ctx), @@ -539,7 +540,7 @@ void addNetRouteJobs(Context *ctx, IdString net_name, std::unordered_map<IdStrin if (net_cache[user_idx]) continue; - auto dst_wire = ctx->getNetinfoSinkWire(net_info, user_idx); + auto dst_wire = ctx->getNetinfoSinkWire(net_info, net_info->users[user_idx]); if (dst_wire == WireId()) log_error("No wire found for port %s on destination cell %s.\n", net_info->users[user_idx].port.c_str(ctx), @@ -614,6 +615,8 @@ bool router1(Context *ctx) if (ctx->verbose || iterCnt == 1) log_info("routing queue contains %d jobs.\n", int(jobQueue.size())); + else if (ctx->slack_redist_iter > 0 && iterCnt % ctx->slack_redist_iter == 0) + assign_budget(ctx, true /* quiet */); bool printNets = ctx->verbose && (jobQueue.size() < 10); @@ -764,7 +767,7 @@ bool router1(Context *ctx) bool got_negative_slack = false; NetInfo *net_info = ctx->nets.at(net_it.first).get(); for (int user_idx = 0; user_idx < int(net_info->users.size()); user_idx++) { - delay_t arc_delay = ctx->getNetinfoRouteDelay(net_info, user_idx); + delay_t arc_delay = ctx->getNetinfoRouteDelay(net_info, net_info->users[user_idx]); delay_t arc_budget = net_info->users[user_idx].budget; delay_t arc_slack = arc_budget - arc_delay; if (arc_slack < 0) { @@ -776,7 +779,8 @@ bool router1(Context *ctx) if (ctx->verbose) log_info(" arc %s -> %s has %f ns slack (delay %f, budget %f)\n", ctx->getWireName(ctx->getNetinfoSourceWire(net_info)).c_str(ctx), - ctx->getWireName(ctx->getNetinfoSinkWire(net_info, user_idx)).c_str(ctx), + ctx->getWireName(ctx->getNetinfoSinkWire(net_info, net_info->users[user_idx])) + .c_str(ctx), ctx->getDelayNS(arc_slack), ctx->getDelayNS(arc_delay), ctx->getDelayNS(arc_budget)); tns += ctx->getDelayNS(arc_slack); @@ -811,6 +815,7 @@ 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 4486fc24..2beaeee9 100644 --- a/common/timing.cc +++ b/common/timing.cc @@ -22,19 +22,29 @@ #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; @@ -47,74 +57,158 @@ static delay_t follow_user_port(Context *ctx, PortRef &user, int path_length, de if (is_path) { NetInfo *net = port.second.net; if (net) { - delay_t path_budget = follow_net(ctx, net, path_length, slack - comb_delay.maxDelay()); + 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)); + 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, usr, net_budget); + if (budget < net_budget) { + net_budget = budget; + pl = std::max(1, path_length); + } + auto delay = ctx->getNetinfoRouteDelay(net, usr); + 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 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 slack = default_slack; // TODO: clock constraints DelayInfo clkToQ; if (ctx->getCellDelay(cell.second.get(), clock_domain, port.first, 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()); + // For slack redistribution, if user has not specified a frequency + // dynamically adjust the target frequency to be the currently + // achieved maximum + if (!ctx->user_freq && ctx->slack_redist_iter > 0) { + 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; + 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, *sink); + 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 |