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rsz: skip ensureWireParasitic in repair_design hot path #10507

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rsz: skip ensureWireParasitic in repair_design hot path #10507

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3 changes: 2 additions & 1 deletion src/rsz/include/rsz/Resizer.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -641,7 +641,8 @@ class Resizer : public sta::dbStaState, public sta::dbNetworkObserver
bool getCin(const sta::LibertyCell* cell, float& cin);
// Resize drvr_pin instance to target slew.
// Return 1 if resized.
int resizeToTargetSlew(const sta::Pin* drvr_pin);
int resizeToTargetSlew(const sta::Pin* drvr_pin,
std::optional<float> load_cap_hint = std::nullopt);

// Resize drvr_pin instance to target cap ratio.
// Return 1 if resized.
Expand Down
24 changes: 17 additions & 7 deletions src/rsz/src/RepairDesign.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1592,6 +1592,10 @@ void RepairDesign::repairNetWire(
double d = (length == 0) ? 0.0 : buf_dist / length;
int buf_x = to_x + d * dx;
int buf_y = to_y + d * dy;
// Buffer is inserted at buf_dist from to_pt, so it drives only the
// downstream wire (buf_dist long) + ref_cap, not the full Steiner edge.
const float buffer_load_cap
= static_cast<float>(buf_dist / (dbu_ * 1e+6) * wire_cap + ref_cap);
float repeater_cap, repeater_fanout;
if (!makeRepeater("wire",
odb::Point(buf_x, buf_y),
Expand All @@ -1601,7 +1605,8 @@ void RepairDesign::repairNetWire(
load_pins,
repeater_cap,
repeater_fanout,
max_load_slew)) {
max_load_slew,
/* load_cap_hint= */ buffer_load_cap)) {
debugPrint(logger_,
RSZ,
"repair_net",
Expand Down Expand Up @@ -1796,7 +1801,8 @@ void RepairDesign::repairNetJunc(
loads_left,
cap_left,
fanout_left,
max_load_slew_left);
max_load_slew_left,
/* load_cap_hint= */ cap_left);
wire_length_left = 0;
}
if (repeater_right) {
Expand All @@ -1808,7 +1814,8 @@ void RepairDesign::repairNetJunc(
loads_right,
cap_right,
fanout_right,
max_load_slew_right);
max_load_slew_right,
/* load_cap_hint= */ cap_right);
wire_length_right = 0;
}

Expand Down Expand Up @@ -2121,7 +2128,8 @@ bool RepairDesign::makeRepeater(const char* reason,
sta::PinSeq& load_pins,
float& repeater_cap,
float& repeater_fanout,
float& repeater_max_slew)
float& repeater_max_slew,
std::optional<float> load_cap_hint)
{
sta::Net* out_net;
sta::Pin *repeater_in_pin, *repeater_out_pin;
Expand All @@ -2137,7 +2145,8 @@ bool RepairDesign::makeRepeater(const char* reason,
repeater_max_slew,
out_net,
repeater_in_pin,
repeater_out_pin);
repeater_out_pin,
load_cap_hint);
}

////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -2172,7 +2181,8 @@ bool RepairDesign::makeRepeater(
float& repeater_max_slew,
sta::Net*& out_net,
sta::Pin*& repeater_in_pin,
sta::Pin*& repeater_out_pin)
sta::Pin*& repeater_out_pin,
std::optional<float> load_cap_hint)
{
debugPrint(logger_,
RSZ,
Expand Down Expand Up @@ -2212,7 +2222,7 @@ bool RepairDesign::makeRepeater(
// Resize repeater as we back up by levels.
if (resize) {
sta::Pin* buffer_out_pin = network_->findPin(buffer, buffer_output_port);
resizer_->resizeToTargetSlew(buffer_out_pin);
resizer_->resizeToTargetSlew(buffer_out_pin, load_cap_hint);
buffer_cell = network_->libertyCell(buffer);
buffer_cell->bufferPorts(buffer_input_port, buffer_output_port);
}
Expand Down
6 changes: 4 additions & 2 deletions src/rsz/src/RepairDesign.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -216,7 +216,8 @@ class RepairDesign : sta::dbStaState
sta::PinSeq& load_pins,
float& repeater_cap,
float& repeater_fanout,
float& repeater_max_slew);
float& repeater_max_slew,
std::optional<float> load_cap_hint = std::nullopt);
bool makeRepeater(const char* reason,
int x,
int y,
Expand All @@ -230,7 +231,8 @@ class RepairDesign : sta::dbStaState
float& repeater_max_slew,
sta::Net*& out_net,
sta::Pin*& repeater_in_pin,
sta::Pin*& repeater_out_pin);
sta::Pin*& repeater_out_pin,
std::optional<float> load_cap_hint = std::nullopt);
sta::LibertyCell* findBufferUnderSlew(float max_slew, float load_cap);
bool hasInputPort(const sta::Net* net);
double dbuToMeters(int dist) const;
Expand Down
20 changes: 15 additions & 5 deletions src/rsz/src/Resizer.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -2533,7 +2533,8 @@ VTCategory Resizer::cellVTType(dbMaster* master)
return new_it->second;
}

int Resizer::resizeToTargetSlew(const sta::Pin* drvr_pin)
int Resizer::resizeToTargetSlew(const sta::Pin* drvr_pin,
std::optional<float> load_cap_hint)
{
sta::Instance* inst = network_->instance(drvr_pin);
sta::LibertyCell* cell = network_->libertyCell(inst);
Expand All @@ -2550,10 +2551,19 @@ int Resizer::resizeToTargetSlew(const sta::Pin* drvr_pin)
revisiting_inst ? " - revisit" : "");
resized_multi_output_insts_.insert(inst);
}
estimate_parasitics_->ensureWireParasitic(drvr_pin);
// Includes net parasitic capacitance.
float load_cap
= graph_delay_calc_->loadCap(drvr_pin, tgt_slew_corner_, max_);
// Hint skips ensureWireParasitic, which triggers an incremental
// FastRoute per buffer in the repair_design.
// Only applies under global-routing parasitics;
// placement-based estimation is already cheap.
float load_cap;
if (load_cap_hint.has_value()
&& estimate_parasitics_->getParasiticsSrc()
== est::ParasiticsSrc::kGlobalRouting) {
load_cap = *load_cap_hint;
} else {
estimate_parasitics_->ensureWireParasitic(drvr_pin);
load_cap = graph_delay_calc_->loadCap(drvr_pin, tgt_slew_corner_, max_);
}
if (load_cap > 0.0) {
sta::LibertyCell* target_cell
= findTargetCell(cell, load_cap, revisiting_inst);
Expand Down
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