diff options
Diffstat (limited to 'common/timing.cc')
| -rw-r--r-- | common/timing.cc | 43 |
1 files changed, 25 insertions, 18 deletions
diff --git a/common/timing.cc b/common/timing.cc index d214793c..c00e1ba5 100644 --- a/common/timing.cc +++ b/common/timing.cc @@ -2,6 +2,7 @@ * nextpnr -- Next Generation Place and Route * * Copyright (C) 2018 David Shah <david@symbioticeda.com> + * Copyright (C) 2018 Eddie Hung <eddieh@ece.ubc.ca> * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above @@ -32,36 +33,42 @@ typedef std::map<int, unsigned> DelayFrequency; struct Timing { Context *ctx; + bool net_delays; bool update; delay_t min_slack; PortRefVector current_path; PortRefVector *crit_path; DelayFrequency *slack_histogram; - Timing(Context *ctx, bool update, PortRefVector *crit_path = nullptr, DelayFrequency *slack_histogram = nullptr) - : ctx(ctx), update(update), min_slack(1.0e12 / ctx->target_freq), crit_path(crit_path), - slack_histogram(slack_histogram) + Timing(Context *ctx, bool net_delays, bool update, PortRefVector *crit_path = nullptr, + DelayFrequency *slack_histogram = nullptr) + : ctx(ctx), net_delays(net_delays), update(update), min_slack(1.0e12 / ctx->target_freq), + crit_path(crit_path), slack_histogram(slack_histogram) { } delay_t follow_net(NetInfo *net, int path_length, delay_t slack) { - delay_t net_budget = slack / (path_length + 1); + const delay_t default_budget = slack / (path_length + 1); + delay_t net_budget = default_budget; for (auto &usr : net->users) { + auto delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t(); 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); + // If budget override exists, use that value and do not increment path_length + auto budget = default_budget; + if (ctx->getBudgetOverride(net, usr, budget)) { + if (update) + usr.budget = std::min(usr.budget, budget); + budget = follow_user_port(usr, path_length, slack - budget); + net_budget = std::min(net_budget, budget); + } + else { + budget = follow_user_port(usr, path_length + 1, slack - delay); + net_budget = std::min(net_budget, budget); + if (update) + usr.budget = std::min(usr.budget, delay + budget); } - auto delay = ctx->getNetinfoRouteDelay(net, usr); - net_budget = std::min(net_budget, follow_user_port(usr, pl, slack - delay)); - if (update) - usr.budget = std::min(usr.budget, delay + net_budget); if (crit_path) current_path.pop_back(); } @@ -149,10 +156,10 @@ void assign_budget(Context *ctx, bool quiet) { if (!quiet) { log_break(); - log_info("Annotating ports with timing budgets for target frequency %.2f MHz\n", ctx->target_freq/1e6); + log_info("Annotating ports with timing budgets for target frequency %.2f MHz\n", ctx->target_freq / 1e6); } - Timing timing(ctx, true /* update */); + Timing timing(ctx, ctx->slack_redist_iter > 0 /* net_delays */, true /* update */); timing.assign_budget(); if (!quiet || ctx->verbose) { @@ -194,7 +201,7 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_path) PortRefVector crit_path; DelayFrequency slack_histogram; - Timing timing(ctx, false /* update */, print_path ? &crit_path : nullptr, + Timing timing(ctx, true /* net_delays */, false /* update */, print_path ? &crit_path : nullptr, print_histogram ? &slack_histogram : nullptr); auto min_slack = timing.walk_paths(); |