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Merge pull request #6248 from eder-matheus/grt_layer_out_of_range
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grt: avoid segments out of layer range in congested routing
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@eder-matheus
eder-matheus authored Nov 27, 2024
2 parents 3501a4c + 5ee297e commit 421bcd9
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Showing 8 changed files with 1,920 additions and 1,431 deletions.
8 changes: 2 additions & 6 deletions src/grt/src/MakeWireParasitics.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -184,17 +184,13 @@ void MakeWireParasitics::makeRouteParasitics(
NodeRoutePtMap& node_map)
{
const int min_routing_layer = grouter_->getMinRoutingLayer();
const bool is_congested = grouter_->isCongested();

size_t resistor_id_ = 1;
for (GSegment& segment : route) {
const int wire_length_dbu = segment.length();

const int init_layer = segment.init_layer;
// allow segments out of the layer range only when the design have
// congestion, becaus GRT may produce segments out of the layer range in
// this scenario.
bool is_valid_layer = init_layer >= min_routing_layer || is_congested;
bool is_valid_layer = init_layer >= min_routing_layer;
sta::ParasiticNode* n1 = is_valid_layer
? ensureParasiticNode(segment.init_x,
segment.init_y,
Expand All @@ -205,7 +201,7 @@ void MakeWireParasitics::makeRouteParasitics(
: nullptr;

const int final_layer = segment.final_layer;
is_valid_layer = final_layer >= min_routing_layer || is_congested;
is_valid_layer = final_layer >= min_routing_layer;
sta::ParasiticNode* n2 = is_valid_layer
? ensureParasiticNode(segment.final_x,
segment.final_y,
Expand Down
91 changes: 40 additions & 51 deletions src/grt/src/fastroute/src/utility.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -494,10 +494,10 @@ void FastRouteCore::assignEdge(int netID, int edgeID, bool processDIR)
}
}

if (best_cost
<= 0) { // assigning the edge to the layer range would cause overflow
// try to assign the edge to the closest layer below the min routing
// layer
// assigning the edge to the layer range would cause overflow try to
// assign the edge to the closest layer below the min routing layer.
// if design has 2D overflow, accept the congestion in layer assignment
if (best_cost <= 0 && !has_2D_overflow_) {
int min_layer = net->getMinLayer();
for (l = net->getMinLayer() - 1; l >= 0; l--) {
fixEdgeAssignment(min_layer,
Expand Down Expand Up @@ -549,10 +549,10 @@ void FastRouteCore::assignEdge(int netID, int edgeID, bool processDIR)
}
}

if (best_cost
<= 0) { // assigning the edge to the layer range would cause overflow
// try to assign the edge to the closest layer below the min routing
// layer
// assigning the edge to the layer range would cause overflow try to
// assign the edge to the closest layer below the min routing layer.
// if design has 2D overflow, accept the congestion in layer assignment
if (best_cost <= 0 && !has_2D_overflow_) {
int min_layer = net->getMinLayer();
for (l = net->getMinLayer() - 1; l >= 0; l--) {
fixEdgeAssignment(min_layer,
Expand Down Expand Up @@ -621,7 +621,8 @@ void FastRouteCore::assignEdge(int netID, int edgeID, bool processDIR)
for (l = 0; l < num_layers_; l++) {
if (layer_grid[l][k] > 0) {
gridD[l][k + 1] = gridD[l][k] + 1;
} else if (layer_grid[l][k] == std::numeric_limits<int>::min()) {
} else if (layer_grid[l][k] == std::numeric_limits<int>::min()
|| l < net->getMinLayer() || l > net->getMaxLayer()) {
// when the layer orientation doesn't match the edge orientation,
// set a larger weight to avoid assigning to this layer when the
// routing has 3D overflow
Expand Down Expand Up @@ -736,7 +737,8 @@ void FastRouteCore::assignEdge(int netID, int edgeID, bool processDIR)
for (l = 0; l < num_layers_; l++) {
if (layer_grid[l][k - 1] > 0) {
gridD[l][k - 1] = gridD[l][k] + 1;
} else if (layer_grid[l][k] == std::numeric_limits<int>::min()) {
} else if (layer_grid[l][k] == std::numeric_limits<int>::min()
|| l < net->getMinLayer() || l > net->getMaxLayer()) {
// when the layer orientation doesn't match the edge orientation,
// set a larger weight to avoid assigning to this layer when the
// routing has 3D overflow
Expand Down Expand Up @@ -962,9 +964,8 @@ void FastRouteCore::layerAssignmentV4()
}

treenodes[n2a].assigned = true;

} // edge len > 0
} // eunmerating edges
}
}
}
}

Expand Down Expand Up @@ -2139,8 +2140,7 @@ int FastRouteCore::edgeShift(Tree& t, int net)
// add the cost of all edges adjacent to the two steiner nodes
for (l = 0; l < nbrCnt[n1]; l++) {
n3 = nbr[n1][l];
if (n3 != n2) // exclude current edge n1-n2
{
if (n3 != n2) { // exclude current edge n1-n2
cost1 = cost2 = 0;
if (t.branch[n1].x < t.branch[n3].x) {
smallX = t.branch[n1].x;
Expand All @@ -2165,12 +2165,11 @@ int FastRouteCore::edgeShift(Tree& t, int net)
cost2 += v_edges_[m][smallX].est_usage;
}
costH[j] += std::min(cost1, cost2);
} // if(n3!=n2)
} // loop l
}
}
for (l = 0; l < nbrCnt[n2]; l++) {
n3 = nbr[n2][l];
if (n3 != n1) // exclude current edge n1-n2
{
if (n3 != n1) { // exclude current edge n1-n2
cost1 = cost2 = 0;
if (t.branch[n2].x < t.branch[n3].x) {
smallX = t.branch[n2].x;
Expand All @@ -2195,9 +2194,9 @@ int FastRouteCore::edgeShift(Tree& t, int net)
cost2 += v_edges_[m][smallX].est_usage;
}
costH[j] += std::min(cost1, cost2);
} // if(n3!=n1)
} // loop l
} // loop j
}
}
}
bestCost = BIG_INT;
Pos = t.branch[n1].y;
for (j = minY; j <= maxY; j++) {
Expand All @@ -2206,8 +2205,7 @@ int FastRouteCore::edgeShift(Tree& t, int net)
Pos = j;
}
}
if (Pos != t.branch[n1].y) // find a better position than current
{
if (Pos != t.branch[n1].y) { // find a better position than current
benefit = costH[t.branch[n1].y] - bestCost;
if (benefit > bestBenefit) {
bestBenefit = benefit;
Expand All @@ -2217,8 +2215,7 @@ int FastRouteCore::edgeShift(Tree& t, int net)
}
}

} else // a vertical edge
{
} else { // a vertical edge
// find the shifting range for the edge (minX~maxX)
maxX1 = minX1 = t.branch[n1].x;
for (j = 0; j < 3; j++) {
Expand All @@ -2240,8 +2237,7 @@ int FastRouteCore::edgeShift(Tree& t, int net)
maxX = std::min(maxX1, maxX2);

// find the best position (least total usage) to shift
if (minX < maxX) // more than 1 possible positions
{
if (minX < maxX) { // more than 1 possible positions
for (j = minX; j <= maxX; j++) {
costV[j] = 0;
for (k = t.branch[n1].y; k < t.branch[n2].y; k++) {
Expand Down Expand Up @@ -2276,12 +2272,11 @@ int FastRouteCore::edgeShift(Tree& t, int net)
cost2 += v_edges_[m][smallX].est_usage;
}
costV[j] += std::min(cost1, cost2);
} // if(n3!=n2)
} // loop l
}
}
for (l = 0; l < nbrCnt[n2]; l++) {
n3 = nbr[n2][l];
if (n3 != n1) // exclude current edge n1-n2
{
if (n3 != n1) { // exclude current edge n1-n2
cost1 = cost2 = 0;
if (j < t.branch[n3].x) {
smallX = j;
Expand All @@ -2306,9 +2301,9 @@ int FastRouteCore::edgeShift(Tree& t, int net)
cost2 += v_edges_[m][smallX].est_usage;
}
costV[j] += std::min(cost1, cost2);
} // if(n3!=n1)
} // loop l
} // loop j
}
}
}
bestCost = BIG_INT;
Pos = t.branch[n1].x;
for (j = minX; j <= maxX; j++) {
Expand All @@ -2317,8 +2312,7 @@ int FastRouteCore::edgeShift(Tree& t, int net)
Pos = j;
}
}
if (Pos != t.branch[n1].x) // find a better position than current
{
if (Pos != t.branch[n1].x) { // find a better position than current
benefit = costV[t.branch[n1].x] - bestCost;
if (benefit > bestBenefit) {
bestBenefit = benefit;
Expand All @@ -2327,27 +2321,23 @@ int FastRouteCore::edgeShift(Tree& t, int net)
}
}
}

} // else (a vertical edge)

} // loop i
}
}

if (bestBenefit > 0) {
n1 = pairN1[bestPair];
n2 = pairN2[bestPair];

if (t.branch[n1].y == t.branch[n2].y) // horizontal edge
{
if (t.branch[n1].y == t.branch[n2].y) { // horizontal edge
t.branch[n1].y = bestPos;
t.branch[n2].y = bestPos;
} // vertical edge
else {
} else { // vertical edge
t.branch[n1].x = bestPos;
t.branch[n2].x = bestPos;
}
numShift++;
}
} // while(bestBenefit>0)
}

return (numShift);
}
Expand Down Expand Up @@ -2453,13 +2443,12 @@ int FastRouteCore::edgeShiftNew(Tree& t, int net)
}
numShift += edgeShift(t, net);
}
} // if(isPair)
}

} // if(pairCnt>0)
else
} else {
iter = 3;

} // while
}
}

return (numShift);
}
Expand Down
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