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Code Issues Releases Wiki Activity

heap: Allow chains to ripup other chains (opt-in only) (#1552)

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Signed-off-by: gatecat <gatecat@ds0.me>
This commit is contained in:
myrtle 2025-09-05 09:02:19 +02:00 committed by GitHub
parent 141abe60a6
commit 9715a1d565
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GPG Key ID: B5690EEEBB952194
3 changed files with 38 additions and 18 deletions
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50
common/place/placer_heap.cc
View File

@ -865,6 +865,7 @@ class HeAPPlacer
remaining.emplace(chain_size[cell->name] * cfg.get_cell_legalisation_weight(ctx, cell), cell->name);
}
int ripup_radius = 2;
int chain_ripup_radius = std::max(max_x, max_y); // only ripup chains as last resort
int total_iters = 0;
int total_iters_noreset = 0;
while (!remaining.empty()) {
@ -1054,7 +1055,7 @@ class HeAPPlacer
// List of cells and their destination
std::vector<std::pair<CellInfo *, BelId>> targets;
// List of bels we placed things at; and the cell that was there before if applicable
std::vector<std::pair<BelId, CellInfo *>> swaps_made;
dict<BelId, CellInfo *> moves_made;
if (!ctx->getClusterPlacement(ci->cluster, sz, targets))
continue;
@ -1065,31 +1066,45 @@ class HeAPPlacer
goto fail;
CellInfo *bound = ctx->getBoundBelCell(target.second);
// Chains cannot overlap; so if we have to ripup a cell make sure it isn't part of a chain
if (bound != nullptr)
if (bound->cluster != ClusterId() || bound->belStrength > STRENGTH_WEAK)
if (bound != nullptr) {
if (bound->belStrength > (cfg.chainRipup ? STRENGTH_STRONG : STRENGTH_WEAK))
goto fail;
if (bound->cluster != ClusterId() && (!cfg.chainRipup || radius < chain_ripup_radius))
goto fail;
}
}
// Actually perform the move; keeping track of the moves we make so we can revert them if needed
for (auto &target : targets) {
CellInfo *bound = ctx->getBoundBelCell(target.second);
if (bound != nullptr)
ctx->unbindBel(target.second);
if (bound != nullptr) {
if (bound->cluster != ClusterId()) {
for (auto cell : cluster2cells[bound->cluster]) {
if (cell->bel != BelId()) {
moves_made[cell->bel] = cell;
ctx->unbindBel(cell->bel);
}
}
} else {
ctx->unbindBel(target.second);
}
}
ctx->bindBel(target.second, target.first, STRENGTH_STRONG);
swaps_made.emplace_back(target.second, bound);
moves_made[target.second] = bound;
}
// Check that the move we have made is legal
for (auto &sm : swaps_made) {
if (!ctx->isBelLocationValid(sm.first))
for (auto &move : moves_made) {
if (!ctx->isBelLocationValid(move.first))
goto fail;
}
if (false) {
fail:
// If the move turned out to be illegal; revert all the moves we made
for (auto &swap : swaps_made) {
ctx->unbindBel(swap.first);
if (swap.second != nullptr)
ctx->bindBel(swap.first, swap.second, STRENGTH_WEAK);
for (auto &move : moves_made) {
if (ctx->getBoundBelCell(move.first))
ctx->unbindBel(move.first);
if (move.second != nullptr)
ctx->bindBel(move.first, move.second, STRENGTH_WEAK);
}
continue;
}
@ -1099,12 +1114,12 @@ class HeAPPlacer
cell_locs[target.first->name].y = loc.y;
// log_info("%s %d %d %d\n", target.first->name.c_str(ctx), loc.x, loc.y, loc.z);
}
for (auto &swap : swaps_made) {
for (auto &move : moves_made) {
// Where we have ripped up cells; add them to the queue
if (swap.second != nullptr)
remaining.emplace(chain_size[swap.second->name] *
cfg.get_cell_legalisation_weight(ctx, swap.second),
swap.second->name);
if (move.second != nullptr && (move.second->cluster == ClusterId() || ctx->getClusterRootCell(move.second->cluster) == move.second))
remaining.emplace(chain_size[move.second->name] *
cfg.get_cell_legalisation_weight(ctx, move.second),
move.second->name);
}
placed = true;
@ -1841,6 +1856,7 @@ PlacerHeapCfg::PlacerHeapCfg(Context *ctx)
timing_driven = ctx->setting<bool>("timing_driven");
solverTolerance = 1e-5;
placeAllAtOnce = false;
chainRipup = false;
int timeout_divisor = ctx->setting<int>("placerHeap/cellPlacementTimeout", 8);
if (timeout_divisor > 0) {

1
common/place/placer_heap.h
View File

@ -45,6 +45,7 @@ struct PlacerHeapCfg
bool placeAllAtOnce;
float netShareWeight;
bool parallelRefine;
bool chainRipup;
int cell_placement_timeout;
int hpwl_scale_x, hpwl_scale_y;

5
himbaechel/uarch/gatemate/gatemate.cc
View File

@ -456,7 +456,10 @@ void GateMateImpl::expandBoundingBox(BoundingBox &bb) const
bb.y1 = std::min((bb.y1 & 0xfffe) + 5, ctx->getGridDimY());
}
void GateMateImpl::configurePlacerHeap(PlacerHeapCfg &cfg) { cfg.placeAllAtOnce = true; }
void GateMateImpl::configurePlacerHeap(PlacerHeapCfg &cfg) {
cfg.chainRipup = true;
cfg.placeAllAtOnce = true;
}
int GateMateImpl::get_dff_config(CellInfo *dff) const
{