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placer1: New temperature heuristic

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2018-12-10 18:53:21 +00:00
parent 222abb5be2
commit 0cb351df52
3 changed files with 18 additions and 19 deletions
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4
common/command.cc
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@ -122,6 +122,7 @@ po::options_description CommandHandler::getGeneralOptions()
general.add_options()("randomize-seed,r", "randomize seed value for random number generator"); general.add_options()("randomize-seed,r", "randomize seed value for random number generator");
general.add_options()("slack_redist_iter", po::value<int>(), "number of iterations between slack redistribution"); general.add_options()("slack_redist_iter", po::value<int>(), "number of iterations between slack redistribution");
general.add_options()("cstrweight", po::value<float>(), "placer weighting for relative constraint satisfaction"); general.add_options()("cstrweight", po::value<float>(), "placer weighting for relative constraint satisfaction");
general.add_options()("starttemp", po::value<float>(), "placer SA start temperature");
general.add_options()("placer-budgets", "use budget rather than criticality in placer timing weights"); general.add_options()("placer-budgets", "use budget rather than criticality in placer timing weights");
general.add_options()("pack-only", "pack design only without placement or routing"); general.add_options()("pack-only", "pack design only without placement or routing");
@ -188,6 +189,9 @@ void CommandHandler::setupContext(Context *ctx)
if (vm.count("cstrweight")) { if (vm.count("cstrweight")) {
settings->set("placer1/constraintWeight", vm["cstrweight"].as<float>()); settings->set("placer1/constraintWeight", vm["cstrweight"].as<float>());
} }
if (vm.count("starttemp")) {
settings->set("placer1/startTemp", vm["starttemp"].as<float>());
}
if (vm.count("placer-budgets")) { if (vm.count("placer-budgets")) {
settings->set("placer1/budgetBased", true); settings->set("placer1/budgetBased", true);

32
common/placer1.cc
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@ -202,7 +202,7 @@ class SAPlacer
wirelen_t min_wirelen = curr_wirelen_cost; wirelen_t min_wirelen = curr_wirelen_cost;
int n_no_progress = 0; int n_no_progress = 0;
temp = 1; temp = cfg.startTemp;
// Main simulated annealing loop // Main simulated annealing loop
for (int iter = 1;; iter++) { for (int iter = 1;; iter++) {
@ -255,8 +255,6 @@ class SAPlacer
int M = std::max(max_x, max_y) + 1; int M = std::max(max_x, max_y) + 1;
double upper = 0.6, lower = 0.4;
if (ctx->verbose) if (ctx->verbose)
log("iter #%d: temp = %f, timing cost = " log("iter #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f, dia = %d, Ra = %.02f \n", "%.0f, wirelen = %.0f, dia = %d, Ra = %.02f \n",
@ -265,21 +263,16 @@ class SAPlacer
if (curr_wirelen_cost < 0.95 * avg_wirelen && curr_wirelen_cost > 0) { if (curr_wirelen_cost < 0.95 * avg_wirelen && curr_wirelen_cost > 0) {
avg_wirelen = 0.8 * avg_wirelen + 0.2 * curr_wirelen_cost; avg_wirelen = 0.8 * avg_wirelen + 0.2 * curr_wirelen_cost;
} else { } else {
if (Raccept >= 0.8) { double diam_next = diameter * (1.0 - 0.44 + Raccept);
temp *= 0.7; diameter = std::max<int>(1, std::min<int>(M, int(diam_next + 0.5)));
} else if (Raccept > upper) { if (Raccept > 0.96) {
if (diameter < M) temp *= 0.5;
diameter++; } else if (Raccept > 0.8) {
else temp *= 0.9;
temp *= 0.9; } else if (Raccept > 0.15 && diameter > 1) {
} else if (Raccept > lower) {
temp *= 0.95; temp *= 0.95;
} else { } else {
// Raccept < 0.3 temp *= 0.8;
if (diameter > 1)
diameter--;
else
temp *= 0.8;
} }
} }
// Once cooled below legalise threshold, run legalisation and start requiring // Once cooled below legalise threshold, run legalisation and start requiring
@ -553,7 +546,7 @@ class SAPlacer
(1 - lambda) * (double(moveChange.wirelen_delta) / last_wirelen_cost); (1 - lambda) * (double(moveChange.wirelen_delta) / last_wirelen_cost);
n_move++; n_move++;
// SA acceptance criterea // SA acceptance criterea
if (delta < 0 || (temp > 1e-9 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / (5 * temp)))) { if (delta < 0 || (temp > 1e-9 && (ctx->rng() / float(0x3fffffff)) <= std::exp(-delta / temp))) {
n_accept++; n_accept++;
if (ctx->debug) if (ctx->debug)
log_info("accepted chain swap %s\n", cell->name.c_str(ctx)); log_info("accepted chain swap %s\n", cell->name.c_str(ctx));
@ -806,8 +799,8 @@ swap_fail:
std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels; std::vector<std::vector<std::vector<std::vector<BelId>>>> fast_bels;
std::unordered_set<BelId> locked_bels; std::unordered_set<BelId> locked_bels;
bool require_legal = true; bool require_legal = true;
const float legalise_temp = 0.00015; const float legalise_temp = 0.001;
const float post_legalise_temp = 0.0003; const float post_legalise_temp = 0.002;
const float post_legalise_dia_scale = 1.5; const float post_legalise_dia_scale = 1.5;
Placer1Cfg cfg; Placer1Cfg cfg;
}; };
@ -817,6 +810,7 @@ Placer1Cfg::Placer1Cfg(Context *ctx) : Settings(ctx)
constraintWeight = get<float>("placer1/constraintWeight", 10); constraintWeight = get<float>("placer1/constraintWeight", 10);
minBelsForGridPick = get<int>("placer1/minBelsForGridPick", 64); minBelsForGridPick = get<int>("placer1/minBelsForGridPick", 64);
budgetBased = get<bool>("placer1/budgetBased", false); budgetBased = get<bool>("placer1/budgetBased", false);
startTemp = get<float> ("placer1/startTemp", 1);
} }
bool placer1(Context *ctx, Placer1Cfg cfg) bool placer1(Context *ctx, Placer1Cfg cfg)

1
common/placer1.h
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@ -30,6 +30,7 @@ struct Placer1Cfg : public Settings
float constraintWeight; float constraintWeight;
int minBelsForGridPick; int minBelsForGridPick;
bool budgetBased; bool budgetBased;
float startTemp;
}; };
extern bool placer1(Context *ctx, Placer1Cfg cfg); extern bool placer1(Context *ctx, Placer1Cfg cfg);