Merge pull request #9040 from The-OpenROAD-Project-staging/grt-incr-res-aware

grt: incremental resistance aware

Author: eder-matheus

src/grt/src/GlobalRouter.cpp

@@ -5244,6 +5244,8 @@ std::vector<Net*> GlobalRouter::updateDirtyRoutes(bool save_guides)
     }
   }
 
+  fastroute_->setIncrementalGrt(false);
+
   return dirty_nets;
 }
 
@@ -5283,6 +5285,7 @@ void GlobalRouter::initFastRouteIncr(std::vector<Net*>& nets)
 {
   initNetlist(nets);
   fastroute_->initAuxVar();
+  fastroute_->setIncrementalGrt(true);
 }
 
 GRouteDbCbk::GRouteDbCbk(GlobalRouter* grouter) : grouter_(grouter)

src/grt/src/fastroute/include/FastRoute.h

@@ -274,6 +274,7 @@ class FastRouteCore
   NetRouteMap getPlanarRoutes();
   void getPlanarRoute(odb::dbNet* db_net, GRoute& route);
   void get3DRoute(odb::dbNet* db_net, GRoute& route);
+  void setIncrementalGrt(bool is_incremental);
 
  private:
   int getEdgeCapacity(FrNet* net, int x1, int y1, EdgeDirection direction);
@@ -617,6 +618,7 @@ class FastRouteCore
   bool resistance_aware_ = false;
   bool enable_resistance_aware_ = false;
   bool is_3d_step_ = false;
+  bool is_incremental_grt_ = false;
   int num_adjust_;
   int v_capacity_;
   int h_capacity_;

src/grt/src/fastroute/src/utility.cpp

@@ -563,6 +563,11 @@ int FastRouteCore::getViaResistance(const int from_layer, const int to_layer)
   return std::ceil(total_via_resistance / default_res);
 }
 
+void FastRouteCore::setIncrementalGrt(bool is_incremental)
+{
+  is_incremental_grt_ = is_incremental;
+}
+
 // Update and sort the nets by the worst slack. Finally pick a percentage of the
 // nets to use the resistance-aware strategy
 void FastRouteCore::updateSlacks(float percentage)
@@ -581,10 +586,16 @@ void FastRouteCore::updateSlacks(float percentage)
 
   for (const int net_id : net_ids_) {
     FrNet* net = nets_[net_id];
+    float slack = 0;
 
-    const float slack = getNetSlack(net->getDbNet());
+    // TODO: Do not update slack during rsz repair
+    // if (en_estimate_parasitics_) {
+    slack = getNetSlack(net->getDbNet());
+    // }
     net->setSlack(slack);
-    net->setIsResAware(false);
+
+    // Enable res-aware for clock nets by default
+    net->setIsResAware(net->isClock());
 
     // Skip positive slacks above threshold
     // TODO: need to check this positive slack threshold
@@ -601,6 +612,11 @@ void FastRouteCore::updateSlacks(float percentage)
 
   std::stable_sort(res_aware_list.begin(), res_aware_list.end(), compareSlack);
 
+  // During incremental grt, enable res-aware for all nets
+  if (is_incremental_grt_) {
+    percentage = 1;
+  }
+
   // Decide the percentage of nets that will use resistance aware
   for (int i = 0; i < res_aware_list.size() * percentage; i++) {
     nets_[res_aware_list[i].first]->setIsResAware(true);