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mpl: add support for IO Pads #6600

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Feb 7, 2025
Merged

mpl: add support for IO Pads #6600

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2 changes: 1 addition & 1 deletion src/mpl/src/SimulatedAnnealingCore.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -302,7 +302,7 @@ void SimulatedAnnealingCore<T>::calWirelength()
T& source = macros_[net.terminals.first];
T& target = macros_[net.terminals.second];

if (target.isIOCluster()) {
if (target.isClusterOfUnplacedIOPins()) {
addBoundaryDistToWirelength(source, target, net.weight);
continue;
}
Expand Down
122 changes: 88 additions & 34 deletions src/mpl/src/clusterEngine.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -65,11 +65,12 @@ void ClusteringEngine::run()
createRoot();
setBaseThresholds();

mapIOPinsAndPads();
createDataFlow();

createIOClusters();
classifyBoundariesStateForIOs();

createDataFlow();

if (design_metrics_->getNumStdCell() == 0) {
logger_->warn(MPL, 25, "Design has no standard cells!");
tree_->has_std_cells = false;
Expand Down Expand Up @@ -357,13 +358,20 @@ void ClusteringEngine::setBaseThresholds()
tree_->base_min_std_cell);
}

// Group IOs with the same constraints:
// 1. If an IO has a constraint region in a certain boundary,
// it is constrained to that entire boundary.
// 2. If an IO has no constraints, it is constrained to all boundaries.
// An IO Cluster may represent:
// 1. A Group of Unplaced Pins;
// 2. An IO Pad.
//
// For the former, we group IO pins with the same constraints based on:
// - If an IO pin has a constraint region in a certain boundary,
// it is constrained to that entire boundary;
// - If an IO pin has no constraints, it is constrained to all boundaries.
void ClusteringEngine::createIOClusters()
{
mapIOPads();
if (!tree_->maps.pad_to_bterm.empty()) {
createIOPadClusters();
return;
}

// Boundary with constrained IOs -> cluster
std::map<Boundary, Cluster*> boundary_to_cluster;
Expand Down Expand Up @@ -434,7 +442,7 @@ void ClusteringEngine::createIOCluster(
setIOClusterDimensions(die, constraint_boundary, x, y, width, height);
}

cluster->setAsIOCluster(
cluster->setAsClusterOfUnplacedIOPins(
std::pair<float, float>(block_->dbuToMicrons(x), block_->dbuToMicrons(y)),
block_->dbuToMicrons(width),
block_->dbuToMicrons(height),
Expand Down Expand Up @@ -512,7 +520,7 @@ void ClusteringEngine::setIOClusterDimensions(const odb::Rect& die,
}
}

void ClusteringEngine::mapIOPads()
void ClusteringEngine::mapIOPinsAndPads()
{
bool design_has_io_pads = false;
for (auto inst : block_->getInsts()) {
Expand All @@ -531,17 +539,56 @@ void ClusteringEngine::mapIOPads()
continue;
}

// If the design has IO pads, there is a net
// connecting the IO pin and IO pad instance
for (odb::dbBTerm* bterm : net->getBTerms()) {
for (odb::dbITerm* iterm : net->getITerms()) {
odb::dbInst* inst = iterm->getInst();
tree_->maps.bterm_to_inst[bterm] = inst;
tree_->maps.pad_to_bterm[inst] = bterm;
tree_->maps.bterm_to_pad[bterm] = inst;
}
}
}
}

void ClusteringEngine::createIOPadClusters()
{
for (const auto& io_pad_path : data_connections_.io_and_regs) {
// Registers or Macros
const PathInsts& connected_insts = io_pad_path.second;
bool path_is_empty = true;
for (const std::set<odb::dbInst*>& insts_of_curr_hop_dist :
connected_insts) {
if (!insts_of_curr_hop_dist.empty()) {
path_is_empty = false;
break;
}
}

if (path_is_empty) {
continue;
}

odb::dbBTerm* bterm = io_pad_path.first;
odb::dbInst* pad = tree_->maps.bterm_to_pad.at(bterm);

createIOPadCluster(pad, bterm);
}
}

void ClusteringEngine::createIOPadCluster(odb::dbInst* pad, odb::dbBTerm* bterm)
{
auto cluster = std::make_unique<Cluster>(id_, pad->getName(), logger_);
tree_->maps.bterm_to_cluster_id[bterm] = id_;
tree_->maps.id_to_cluster[id_++] = cluster.get();

const odb::Rect& pad_bbox = pad->getBBox()->getBox();

cluster->setAsIOPadCluster({block_->dbuToMicrons(pad_bbox.xMin()),
block_->dbuToMicrons(pad_bbox.yMin())},
block_->dbuToMicrons(pad_bbox.dx()),
block_->dbuToMicrons(pad_bbox.dy()));
tree_->root->addChild(std::move(cluster));
}

// Dataflow is used to improve quality of macro placement.
// Here we model each std cell instance, IO pin and macro pin as vertices.
void ClusteringEngine::createDataFlow()
Expand Down Expand Up @@ -682,23 +729,25 @@ DataFlowHypergraph ClusteringEngine::computeHypergraph(
graph.backward_vertices.resize(num_of_vertices);

for (odb::dbNet* net : block_->getNets()) {
if (net->getSigType().isSupply()) {
if (!isValidNet(net)) {
continue;
}

int driver_id = -1;
std::set<int> loads_id;
bool ignore = false;
bool net_has_stdcell_without_liberty = false;
for (odb::dbITerm* iterm : net->getITerms()) {
odb::dbInst* inst = iterm->getInst();
if (isIgnoredInst(inst)) {
ignore = true;
break;
}

int vertex_id = -1;

if (inst->isBlock()) {
vertex_id = odb::dbIntProperty::find(iterm, "vertex_id")->getValue();
} else if (inst->isPad()) {
// To properly consider the path of a signal that travels from a PAD
// to the core we use the path's bterm as the vertex.
odb::dbBTerm* pad_bterm = tree_->maps.pad_to_bterm.at(inst);
vertex_id
= odb::dbIntProperty::find(pad_bterm, "vertex_id")->getValue();
} else {
odb::dbIntProperty* int_prop
= odb::dbIntProperty::find(inst, "vertex_id");
Expand All @@ -707,7 +756,7 @@ DataFlowHypergraph ClusteringEngine::computeHypergraph(
if (int_prop) {
vertex_id = int_prop->getValue();
} else {
ignore = true;
net_has_stdcell_without_liberty = true;
break;
}
}
Expand All @@ -719,7 +768,7 @@ DataFlowHypergraph ClusteringEngine::computeHypergraph(
}
}

if (ignore) {
if (net_has_stdcell_without_liberty) {
continue;
}

Expand Down Expand Up @@ -1733,21 +1782,15 @@ void ClusteringEngine::updateConnections()
}

for (odb::dbNet* net : block_->getNets()) {
if (net->getSigType().isSupply()) {
if (!isValidNet(net)) {
continue;
}

int driver_cluster_id = -1;
std::vector<int> load_clusters_ids;
bool net_has_pad_or_cover = false;

for (odb::dbITerm* iterm : net->getITerms()) {
odb::dbInst* inst = iterm->getInst();
if (isIgnoredInst(inst)) {
net_has_pad_or_cover = true;
break;
}

const int cluster_id = tree_->maps.inst_to_cluster_id.at(inst);

if (iterm->getIoType() == odb::dbIoType::OUTPUT) {
Expand All @@ -1757,10 +1800,6 @@ void ClusteringEngine::updateConnections()
}
}

if (net_has_pad_or_cover) {
continue;
}

bool net_has_io_pin = false;
for (odb::dbBTerm* bterm : net->getBTerms()) {
const int cluster_id = tree_->maps.bterm_to_cluster_id.at(bterm);
Expand Down Expand Up @@ -1789,6 +1828,21 @@ void ClusteringEngine::updateConnections()
}
}

bool ClusteringEngine::isValidNet(odb::dbNet* net)
{
if (net->getSigType().isSupply()) {
return false;
}

for (odb::dbITerm* iterm : net->getITerms()) {
if (!isIgnoredInst(iterm->getInst())) {
return true;
}
}

return false;
}

void ClusteringEngine::fetchMixedLeaves(
Cluster* parent,
std::vector<std::vector<Cluster*>>& mixed_leaves)
Expand Down Expand Up @@ -2162,7 +2216,7 @@ void ClusteringEngine::printPhysicalHierarchyTree(Cluster* parent, int level)
parent->getId(),
parent->getClusterTypeString());

if (parent->isIOCluster()) {
if (parent->isClusterOfUnplacedIOPins()) {
int number_of_pins = 0;
for (const auto [pin, cluster_id] : tree_->maps.bterm_to_cluster_id) {
if (cluster_id == parent->getId()) {
Expand All @@ -2171,7 +2225,7 @@ void ClusteringEngine::printPhysicalHierarchyTree(Cluster* parent, int level)
}

line += fmt::format(" Pins: {}", number_of_pins);
} else {
} else if (!parent->isIOPadCluster()) {
line += fmt::format(" {}, StdCells: {} ({} μ²), Macros: {} ({} μ²)",
parent->getIsLeafString(),
parent->getNumStdCell(),
Expand Down
19 changes: 11 additions & 8 deletions src/mpl/src/clusterEngine.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@ namespace mpl {

using InstToHardMap = std::map<odb::dbInst*, std::unique_ptr<HardMacro>>;
using ModuleToMetricsMap = std::map<odb::dbModule*, std::unique_ptr<Metrics>>;
using PathInsts = std::vector<std::set<odb::dbInst*>>;

struct DataFlowHypergraph
{
Expand All @@ -80,20 +81,17 @@ struct DataFlow

// Macro Pins --> Registers
// Registers --> Macro Pins
std::vector<std::pair<odb::dbITerm*, std::vector<std::set<odb::dbInst*>>>>
macro_pins_and_regs;
std::vector<std::pair<odb::dbITerm*, PathInsts>> macro_pins_and_regs;

// IO --> Register
// Register --> IO
// IO --> Macro Pin
// Macro Pin --> IO
std::vector<std::pair<odb::dbBTerm*, std::vector<std::set<odb::dbInst*>>>>
io_and_regs;
std::vector<std::pair<odb::dbBTerm*, PathInsts>> io_and_regs;

// Macro Pin --> Macros
// Macros --> Macro Pin
std::vector<std::pair<odb::dbITerm*, std::vector<std::set<odb::dbInst*>>>>
macro_pins_and_macros;
std::vector<std::pair<odb::dbITerm*, PathInsts>> macro_pins_and_macros;
};

struct PhysicalHierarchyMaps
Expand All @@ -106,7 +104,8 @@ struct PhysicalHierarchyMaps
ModuleToMetricsMap module_to_metrics;

// Only for designs with IO Pads
std::map<odb::dbBTerm*, odb::dbInst*> bterm_to_inst;
std::map<odb::dbInst*, odb::dbBTerm*> pad_to_bterm;
std::map<odb::dbBTerm*, odb::dbInst*> bterm_to_pad;
};

struct PhysicalHierarchy
Expand Down Expand Up @@ -191,6 +190,8 @@ class ClusteringEngine
void createRoot();
void setBaseThresholds();
void createIOClusters();
void createIOPadClusters();
void createIOPadCluster(odb::dbInst* pad, odb::dbBTerm* bterm);
void classifyBoundariesStateForIOs();
std::map<Boundary, float> computeBlockageExtensionMap();
Boundary getConstraintBoundary(const odb::Rect& die,
Expand All @@ -205,7 +206,7 @@ class ClusteringEngine
int& y,
int& width,
int& height);
void mapIOPads();
void mapIOPinsAndPads();
void treatEachMacroAsSingleCluster();
void incorporateNewCluster(std::unique_ptr<Cluster> cluster, Cluster* parent);
void setClusterMetrics(Cluster* cluster);
Expand Down Expand Up @@ -279,6 +280,8 @@ class ClusteringEngine
void printPhysicalHierarchyTree(Cluster* parent, int level);
float computeMicronArea(odb::dbInst* inst);

bool isValidNet(odb::dbNet* net);

odb::dbBlock* block_;
sta::dbNetwork* network_;
utl::Logger* logger_;
Expand Down
4 changes: 2 additions & 2 deletions src/mpl/src/graphics.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -444,7 +444,7 @@ void Graphics::drawObjects(gui::Painter& painter)
continue;
}

if (cluster->isIOCluster()) {
if (cluster->isClusterOfUnplacedIOPins()) {
continue;
}

Expand Down Expand Up @@ -607,7 +607,7 @@ void Graphics::drawBundledNets(gui::Painter& painter,
const T& source = macros[bundled_net.terminals.first];
const T& target = macros[bundled_net.terminals.second];

if (target.isIOCluster()) {
if (target.isClusterOfUnplacedIOPins()) {
drawDistToIoConstraintBoundary(painter, source, target);
continue;
}
Expand Down
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