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HeAP: Add SA-based iterative refinement after AP

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2019-01-23 16:36:53 +00:00
parent 0570cb7ae9
commit f3d9b45387
3 changed files with 145 additions and 89 deletions
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49
common/placer1.cc
View File

@ -147,12 +147,15 @@ class SAPlacer
net.second->udata = old_udata[net.second->udata];
}
bool place()
bool place(bool refine = false)
{
log_break();
ctx->lock();
size_t placed_cells = 0;
std::vector<CellInfo *> autoplaced;
std::vector<CellInfo *> chain_basis;
if (!refine) {
// Initial constraints placer
for (auto &cell_entry : ctx->cells) {
CellInfo *cell = cell_entry.second.get();
@ -194,8 +197,7 @@ class SAPlacer
ctx->yield();
// Sort to-place cells for deterministic initial placement
std::vector<CellInfo *> autoplaced;
std::vector<CellInfo *> chain_basis;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
@ -224,8 +226,23 @@ class SAPlacer
ctx->yield();
auto iplace_end = std::chrono::high_resolution_clock::now();
log_info("Initial placement time %.02fs\n", std::chrono::duration<float>(iplace_end - iplace_start).count());
auto saplace_start = std::chrono::high_resolution_clock::now();
log_info("Running simulated annealing placer.\n");
} else {
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
if (ci->belStrength > STRENGTH_STRONG)
continue;
else if (ci->constr_parent != nullptr)
continue;
else if (!ci->constr_children.empty() || ci->constr_z != ci->UNCONSTR)
chain_basis.push_back(ci);
else
autoplaced.push_back(ci);
}
require_legal = false;
diameter = 3;
}
auto saplace_start = std::chrono::high_resolution_clock::now();
// Invoke timing analysis to obtain criticalities
if (!cfg.budgetBased)
@ -242,7 +259,7 @@ class SAPlacer
wirelen_t min_wirelen = curr_wirelen_cost;
int n_no_progress = 0;
temp = cfg.startTemp;
temp = refine ? 1e-8 : cfg.startTemp;
// Main simulated annealing loop
for (int iter = 1;; iter++) {
@ -284,7 +301,7 @@ class SAPlacer
else
n_no_progress++;
if (temp <= 1e-7 && n_no_progress >= 5) {
if (temp <= 1e-7 && n_no_progress >= (refine ? 1 : 5)) {
log_info(" at iteration #%d: temp = %f, timing cost = "
"%.0f, wirelen = %.0f \n",
iter, temp, double(curr_timing_cost), double(curr_wirelen_cost));
@ -934,4 +951,24 @@ bool placer1(Context *ctx, Placer1Cfg cfg)
}
}
bool placer1_refine(Context *ctx, Placer1Cfg cfg) {
try {
SAPlacer placer(ctx, cfg);
placer.place(true);
log_info("Checksum: 0x%08x\n", ctx->checksum());
#ifndef NDEBUG
ctx->lock();
ctx->check();
ctx->unlock();
#endif
return true;
} catch (log_execution_error_exception) {
#ifndef NDEBUG
ctx->check();
#endif
return false;
}
}
NEXTPNR_NAMESPACE_END

1
common/placer1.h
View File

@ -35,6 +35,7 @@ struct Placer1Cfg : public Settings
};
extern bool placer1(Context *ctx, Placer1Cfg cfg);
extern bool placer1_refine(Context *ctx, Placer1Cfg cfg);
NEXTPNR_NAMESPACE_END

30
common/placer_heap.cc
View File

@ -34,6 +34,7 @@
#include "nextpnr.h"
#include "place_common.h"
#include "placer_math.h"
#include "placer1.h"
#include "util.h"
NEXTPNR_NAMESPACE_BEGIN
@ -191,6 +192,9 @@ class HeAPPlacer
++iter;
}
ctx->unlock();
placer1_refine(ctx, Placer1Cfg(ctx));
return true;
}
@ -355,14 +359,17 @@ class HeAPPlacer
// FIXME: Are there better approaches to the initial placement (e.g. greedy?)
void seed_placement()
{
std::unordered_map<IdString, std::vector<BelId>> available_bels;
std::unordered_map<IdString, std::deque<BelId>> available_bels;
for (auto bel : ctx->getBels()) {
if (!ctx->checkBelAvail(bel))
continue;
available_bels[ctx->getBelType(bel)].push_back(bel);
}
for (auto &ab : available_bels)
ctx->shuffle(ab.second);
for (auto &t : available_bels) {
std::random_shuffle(t.second.begin(), t.second.end(), [&](size_t n){
return ctx->rng(int(n));
});
}
for (auto cell : sorted(ctx->cells)) {
CellInfo *ci = cell.second;
if (ci->bel != BelId()) {
@ -372,6 +379,8 @@ class HeAPPlacer
cell_locs[cell.first].locked = true;
cell_locs[cell.first].global = ctx->getBelGlobalBuf(ci->bel);
} else if (ci->constr_parent == nullptr) {
bool placed = false;
while (!placed) {
if (!available_bels.count(ci->type) || available_bels.at(ci->type).empty())
log_error("Unable to place cell '%s', no Bels remaining of type '%s'\n", ci->name.c_str(ctx),
ci->type.c_str(ctx));
@ -385,10 +394,19 @@ class HeAPPlacer
// FIXME
if (has_connectivity(cell.second) && cell.second->type != ctx->id("SB_IO")) {
place_cells.push_back(ci);
placed = true;
} else {
if (ctx->isValidBelForCell(ci, bel)) {
ctx->bindBel(bel, ci, STRENGTH_STRONG);
cell_locs[cell.first].locked = true;
placed = true;
} else {
available_bels.at(ci->type).push_front(bel);
}
}
}
}
}
}
@ -728,8 +746,8 @@ class HeAPPlacer
for (auto &r : regions) {
if (merged_regions.count(r.id))
continue;
/*log_info("%s (%d, %d) |_> (%d, %d) %d/%d\n", beltype.c_str(ctx), r.x0, r.y0, r.x1, r.y1, r.cells,
r.bels);*/
log_info("%s (%d, %d) |_> (%d, %d) %d/%d\n", beltype.c_str(ctx), r.x0, r.y0, r.x1, r.y1, r.cells,
r.bels);
workqueue.emplace(r.id, false);
//cut_region(r, false);
}
@ -865,7 +883,7 @@ class HeAPPlacer
auto process_location = [&](int x, int y) {
// Merge with any overlapping regions
if (groups.at(x).at(y) != r.id) {
if (groups.at(x).at(y) == -1) {
r.bels += bels_at(x, y);
r.cells += occ_at(x, y);
}