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Update grt, drt, rsz utilities to support RC correlation #7254

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Merged
maliberty merged 7 commits into from
Jun 4, 2025
Merged

Update grt, drt, rsz utilities to support RC correlation #7254

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405e4d2
grt: Update layer lengths utility
povik May 1, 2025
6367f72
grt: Fix via print in wirelength reports
povik May 1, 2025
2ba7694
rsz: Add `report_net_parasitic` for debug
povik May 1, 2025
446cd1f
grt: Fix method name typo
povik Apr 28, 2025
eb8cbad
rsz: Add resist summary for RC correlation
povik Apr 28, 2025
3351fe4
drt: Add drt layer length utility
povik May 1, 2025
5f78034
grt: Put back last mile patching in length utility
povik Jun 4, 2025
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2 changes: 2 additions & 0 deletions src/drt/include/triton_route/TritonRoute.h
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Expand Up @@ -20,6 +20,7 @@ class dbDatabase;
class dbInst;
class dbBTerm;
class dbNet;
class dbWire;
} // namespace odb

namespace utl {
Expand Down Expand Up @@ -163,6 +164,7 @@ class TritonRoute
const std::list<std::unique_ptr<frMarker>>& markers,
const std::string& marker_name,
odb::Rect drcBox = odb::Rect(0, 0, 0, 0)) const;
std::vector<int> routeLayerLengths(odb::dbWire* wire) const;
void checkDRC(const char* filename,
int x1,
int y1,
Expand Down
20 changes: 20 additions & 0 deletions src/drt/src/TritonRoute.cpp
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Expand Up @@ -1385,4 +1385,24 @@ void TritonRoute::reportDRC(const std::string& file_name,
tool_category->writeTR(file_name);
}

std::vector<int> TritonRoute::routeLayerLengths(odb::dbWire* wire) const
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@maliberty maliberty May 1, 2025

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Why is this in drt as it appears only use odb APIs?

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@povik povik May 2, 2025

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It makes sense to have drt::route_layer_lengths as an analogue to grt::route_layer_lengths. The latter does use grt APIs so it can't be an odb utility. Should I move the drt one into the odb submodule, or just somewhere else in src/drt/src where it's more decoupled from the router itself?

{
std::vector<int> lengths;
lengths.resize(db_->getTech()->getLayerCount());
odb::dbWireShapeItr shapes;
odb::dbShape s;

for (shapes.begin(wire); shapes.next(s);) {
if (!s.isVia()) {
lengths[s.getTechLayer()->getNumber()] += s.getLength();
} else {
if (s.getTechVia()) {
lengths[s.getTechVia()->getBottomLayer()->getNumber() + 1] += 1;
}
}
}

return lengths;
}

} // namespace drt
12 changes: 12 additions & 0 deletions src/drt/src/TritonRoute.i
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Expand Up @@ -13,6 +13,10 @@

%include "../../Exception.i"

%import <stl.i>
%import <std_vector.i>
%template(vector_int) std::vector<int>;

%inline %{

int detailed_route_num_drvs()
Expand Down Expand Up @@ -218,4 +222,12 @@ void check_drc_cmd(const char* drc_file, int x1, int y1, int x2, int y2, const c
const int num_threads = ord::OpenRoad::openRoad()->getThreadCount();
router->checkDRC(drc_file, x1, y1, x2, y2, marker_name, num_threads);
}

std::vector<int>
route_layer_lengths(odb::dbWire* db_wire)
{
auto* router = ord::OpenRoad::openRoad()->getTritonRoute();
return router->routeLayerLengths(db_wire);
}

%} // inline
10 changes: 6 additions & 4 deletions src/grt/src/GlobalRouter.cpp
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Expand Up @@ -510,7 +510,7 @@ void GlobalRouter::estimateRC(sta::SpefWriter* spef_writer)
for (auto& [db_net, route] : routes_) {
if (!route.empty()) {
Net* net = getNet(db_net);
builder.estimateParasitcs(db_net, net->getPins(), route, spef_writer);
builder.estimateParasitics(db_net, net->getPins(), route, spef_writer);
}
}
}
Expand All @@ -526,7 +526,7 @@ void GlobalRouter::estimateRC(odb::dbNet* db_net)
GRoute& route = iter->second;
if (!route.empty()) {
Net* net = getNet(db_net);
builder.estimateParasitcs(db_net, net->getPins(), route);
builder.estimateParasitics(db_net, net->getPins(), route);
}
}

Expand Down Expand Up @@ -4559,11 +4559,12 @@ void GlobalRouter::reportNetLayerWirelengths(odb::dbNet* db_net,
via_count++;
}
}
out << " " << via_count;
for (size_t i = 0; i < lengths.size(); i++) {
int64_t length = lengths[i];
odb::dbTechLayer* layer = db_->getTech()->findRoutingLayer(i);
if (i > 0 && out.is_open()) {
out << " " << via_count << " " << block_->dbuToMicrons(length);
out << " " << block_->dbuToMicrons(length);
}
if (length > 0) {
logger_->report("\tLayer {:5s}: {:5.2f}um",
Expand Down Expand Up @@ -4692,11 +4693,12 @@ void GlobalRouter::reportNetDetailedRouteWL(odb::dbWire* wire,
}
}

out << " " << via_count;
for (size_t i = 1; i < lengths.size(); i++) {
int64_t length = lengths[i];
odb::dbTechLayer* layer = db_->getTech()->findRoutingLayer(i);
if (i > 0 && out.is_open()) {
out << " " << via_count << " " << block_->dbuToMicrons(length);
out << " " << block_->dbuToMicrons(length);
}
if (length > 0) {
logger_->report("\tLayer {:5s}: {:5.2f}um",
Expand Down
54 changes: 19 additions & 35 deletions src/grt/src/MakeWireParasitics.cpp
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Expand Up @@ -49,10 +49,10 @@ MakeWireParasitics::MakeWireParasitics(utl::Logger* logger,
{
}

void MakeWireParasitics::estimateParasitcs(odb::dbNet* net,
std::vector<Pin>& pins,
GRoute& route,
sta::SpefWriter* spef_writer)
void MakeWireParasitics::estimateParasitics(odb::dbNet* net,
std::vector<Pin>& pins,
GRoute& route,
sta::SpefWriter* spef_writer)
{
debugPrint(logger_, GRT, "est_rc", 1, "net {}", net->getConstName());
if (logger_->debugCheck(GRT, "est_rc", 2)) {
Expand Down Expand Up @@ -93,7 +93,7 @@ void MakeWireParasitics::estimateParasitcs(odb::dbNet* net,
parasitics_->deleteParasiticNetworks(sta_net);
}

void MakeWireParasitics::estimateParasitcs(odb::dbNet* net, GRoute& route)
void MakeWireParasitics::estimateParasitics(odb::dbNet* net, GRoute& route)
{
debugPrint(logger_, GRT, "est_rc", 1, "net {}", net->getConstName());
if (logger_->debugCheck(GRT, "est_rc", 2)) {
Expand Down Expand Up @@ -491,47 +491,31 @@ float MakeWireParasitics::getNetSlack(odb::dbNet* net)
std::vector<int> MakeWireParasitics::routeLayerLengths(odb::dbNet* db_net) const
{
NetRouteMap& routes = grouter_->getRoutes();
std::vector<int> layer_lengths(grouter_->getMaxRoutingLayer() + 1);

// dbu wirelength for wires, via count for vias
std::vector<int> layer_lengths(tech_->getLayerCount());

if (!db_net->getSigType().isSupply()) {
GRoute& route = routes[db_net];
std::set<RoutePt> route_pts;
for (GSegment& segment : route) {
if (segment.isVia()) {
route_pts.insert(
RoutePt(segment.init_x, segment.init_y, segment.init_layer));
route_pts.insert(
RoutePt(segment.final_x, segment.final_y, segment.final_layer));
auto& s = segment;
// Mimic makeRouteParasitics
int min_layer = min(s.init_layer, s.final_layer);
odb::dbTechLayer* cut_layer
= tech_->findRoutingLayer(min_layer)->getUpperLayer();
layer_lengths[cut_layer->getNumber()] += 1;
route_pts.insert(RoutePt(s.init_x, s.init_y, s.init_layer));
route_pts.insert(RoutePt(s.final_x, s.final_y, s.final_layer));
} else {
int layer = segment.init_layer;
layer_lengths[layer] += segment.length();
layer_lengths[tech_->findRoutingLayer(layer)->getNumber()]
+= segment.length();
route_pts.insert(RoutePt(segment.init_x, segment.init_y, layer));
route_pts.insert(RoutePt(segment.final_x, segment.final_y, layer));
}
}
// Mimic MakeWireParasitics::makeParasiticsToPin functionality.
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@maliberty maliberty May 2, 2025

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Why is the following code no longer needed?

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@povik povik May 2, 2025

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My understanding is the grt guides reach the center of the instance not the individual pins, and this code is adding a small patch of route on top of it to meet the pin. In the process it's adding a redundant via (so we overcount), and I'm not sure the wirelength it adds is beneficial either.

If it's true that it doesn't help with the estimation (which can be confirmed empirically) then we should remove the same code from makeParasiticsPin to keep things in sync

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@eder-matheus eder-matheus May 5, 2025

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@povik A small clarification, but GRT guides don't reach the center of the instance. They reach the center of the GCell that encloses the pin shape. The distance from the center of the GCell to the pin location might be useful (more than 7 tracks, for example)

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@maliberty maliberty May 8, 2025

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What is the redundant via that is being added?

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@povik povik May 9, 2025

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Actually the redundant via exists only in makeParasiticsToPin (see via_res in the function). Here it wasn't being counted because we weren't counting vias at all, but now that we do, we would have a redundant via if we updated this piece of code instead of removing it.

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@maliberty maliberty May 9, 2025

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I'm afraid I'm not following. My concern is that if estimate RC is creating a redundant via then it is incorrect and should be fixed. Perhaps you and @eder-matheus can review this issue.

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@povik povik Jun 4, 2025

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We've discussed with @eder-matheus and agreed to put this code back.

My concern is that if estimate RC is creating a redundant via then it is incorrect

There's redundant via in estimate RC but it's a dead end so if STA is considering topology of the parasitic network the extra resistive element is without effect. The length utility doesn't see topology.

Net* net = grouter_->getNet(db_net);
for (Pin& pin : net->getPins()) {
int layer = pin.getConnectionLayer() + 1;
odb::Point grid_pt = pin.getOnGridPosition();
odb::Point pt = pin.getPosition();

std::vector<std::pair<odb::Point, odb::Point>> ap_positions;
bool has_access_points
= grouter_->findPinAccessPointPositions(pin, ap_positions);
if (has_access_points) {
auto ap_position = ap_positions.front();
pt = ap_position.first;
grid_pt = ap_position.second;
}

RoutePt grid_route(grid_pt.getX(), grid_pt.getY(), layer);
auto pt_itr = route_pts.find(grid_route);
if (pt_itr == route_pts.end())
layer--;
int wire_length_dbu
= abs(pt.getX() - grid_pt.getX()) + abs(pt.getY() - grid_pt.getY());
layer_lengths[layer] += wire_length_dbu;
}
}
return layer_lengths;
}
Expand Down
10 changes: 5 additions & 5 deletions src/grt/src/MakeWireParasitics.h
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Expand Up @@ -54,11 +54,11 @@ class MakeWireParasitics : public AbstractMakeWireParasitics
odb::dbTech* tech,
odb::dbBlock* block,
GlobalRouter* grouter);
void estimateParasitcs(odb::dbNet* net,
std::vector<Pin>& pins,
GRoute& route,
sta::SpefWriter* spef_writer = nullptr);
void estimateParasitcs(odb::dbNet* net, GRoute& route) override;
void estimateParasitics(odb::dbNet* net,
std::vector<Pin>& pins,
GRoute& route,
sta::SpefWriter* spef_writer = nullptr);
void estimateParasitics(odb::dbNet* net, GRoute& route) override;

void clearParasitics() override;
// Return GRT layer lengths in dbu's for db_net's route indexed by routing
Expand Down
2 changes: 1 addition & 1 deletion src/grt/src/fastroute/include/AbstractMakeWireParasitics.h
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Expand Up @@ -14,7 +14,7 @@ class AbstractMakeWireParasitics
public:
~AbstractMakeWireParasitics() = default;

virtual void estimateParasitcs(odb::dbNet* net, GRoute& route) = 0;
virtual void estimateParasitics(odb::dbNet* net, GRoute& route) = 0;

virtual void clearParasitics() = 0;

Expand Down
2 changes: 1 addition & 1 deletion src/grt/src/fastroute/src/utility.cpp
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Expand Up @@ -1265,7 +1265,7 @@ float FastRouteCore::CalculatePartialSlack()
odb::dbNet* db_net = net_route.first;
GRoute& route = net_route.second;
if (!route.empty()) {
parasitics_builder_->estimateParasitcs(db_net, route);
parasitics_builder_->estimateParasitics(db_net, route);
}
}
for (const int& netID : net_ids_) {
Expand Down
8 changes: 4 additions & 4 deletions src/grt/test/report_wire_length4.rptok
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@@ -1,5 +1,5 @@
tool net total_wl #pins #vias li1_wl met1_wl met2_wl met3_wl met4_wl met5_wl
grt: clk 201.6 2 2 0 2 0 2 0 2 144 2 57.6 2 0
drt: clk 184.95 2 5 0 5 0.215 5 0.185 5 134.97 5 49.58 5 0
grt: net60 14.4 2 2 0 2 0 2 14.4 2 0 2 0 2 0
drt: net60 13.39 2 3 0 3 3.77 3 9.62 3 0 3 0 3 0
grt: clk 201.6 2 2 0 0 0 144 57.6 0
drt: clk 184.95 2 5 0 0.215 0.185 134.97 49.58 0
grt: net60 14.4 2 2 0 0 14.4 0 0 0
drt: net60 13.39 2 3 0 3.77 9.62 0 0 0
31 changes: 31 additions & 0 deletions src/rsz/src/Resizer.i
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Expand Up @@ -7,6 +7,7 @@
#include <fstream>

#include "sta/Liberty.hh"
#include "sta/Parasitics.hh"
#include "sta/Network.hh"
#include "sta/Corner.hh"
#include "rsz/Resizer.hh"
Expand Down Expand Up @@ -115,6 +116,36 @@ using rsz::ParasiticsSrc;

namespace rsz {

void
report_net_parasitic(Net *net)
{
Resizer *resizer = getResizer();
Corner *corner = sta::Sta::sta()->cmdCorner();
const ParasiticAnalysisPt *ap = corner->findParasiticAnalysisPt(sta::MinMax::max());
auto parasitic = resizer->parasitics()->findParasiticNetwork(net, ap);
if (parasitic) {
resizer->parasitics()->report(parasitic);
}
}

float
sum_parasitic_network_resist(Net *net)
{
Resizer *resizer = getResizer();
Corner *corner = sta::Sta::sta()->cmdCorner();
const ParasiticAnalysisPt *ap = corner->findParasiticAnalysisPt(sta::MinMax::max());
auto parasitic = resizer->parasitics()->findParasiticNetwork(net, ap);
if (parasitic) {
float ret = 0.0;
for (auto resist : resizer->parasitics()->resistors(parasitic)) {
ret += resizer->parasitics()->value(resist);
}
return ret;
} else {
return 0.0f;
}
}

void
set_layer_rc_cmd(odb::dbTechLayer *layer,
const Corner *corner,
Expand Down
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