#2299: Add method with hardcoded load balancing cost

DARMA-tasking · Sep 20, 2024 · a1bd423 · a1bd423
1 parent af09056
commit a1bd423
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Showing 4 changed files with 16 additions and 8 deletions.
diff --git a/src/vt/vrt/collection/balance/baselb/baselb.h b/src/vt/vrt/collection/balance/baselb/baselb.h
@@ -164,6 +164,16 @@ struct BaseLB {
   bool isCommAware() const { return comm_aware_; }
   void recvSharedEdges(CommMsg* msg);
 
+  /**
+   * \brief Get the estimated time needed for load balancing
+   *
+   * \return the estimated time
+   */
+  double getCollectiveEpochCost() const {
+    // 100 ns
+    return 0.0000001;
+  }
+
 protected:
   void getArgs(PhaseType phase);
 

diff --git a/src/vt/vrt/collection/balance/greedylb/greedylb.cc b/src/vt/vrt/collection/balance/greedylb/greedylb.cc
@@ -160,7 +160,8 @@ void GreedyLB::loadStats() {
   bool should_lb = false;
   this_load_begin = this_load;
 
-  if (avg_load > 0.0000000001) {
+  // Use an estimated load-balancing cost on average rank load to load-balance
+  if (avg_load > getCollectiveEpochCost()) {
     should_lb = I > greedy_tolerance;
   }
 

diff --git a/src/vt/vrt/collection/balance/hierarchicallb/hierlb.cc b/src/vt/vrt/collection/balance/hierarchicallb/hierlb.cc
@@ -263,7 +263,8 @@ void HierarchicalLB::loadStats() {
   bool should_lb = false;
   this_load_begin = this_load;
 
-  if (avg_load > 0.0000000001) {
+  // Use an estimated load-balancing cost on average rank load to load-balance
+  if (avg_load > getCollectiveEpochCost()) {
     should_lb = I > hierlb_tolerance;
   }
 

diff --git a/src/vt/vrt/collection/balance/temperedlb/temperedlb.cc b/src/vt/vrt/collection/balance/temperedlb/temperedlb.cc
@@ -58,7 +58,6 @@
 #include <vector>
 #include <unordered_set>
 #include <set>
-#include <limits>
 
 namespace vt { namespace vrt { namespace collection { namespace lb {
 
@@ -439,9 +438,6 @@ void TemperedLB::runLB(LoadType total_load) {
   auto const imb  = stats.at(lb::Statistic::Rank_load_modeled).at(
     lb::StatisticQuantity::imb
   );
-  auto const min = stats.at(lb::Statistic::Object_load_modeled).at(
-    lb::StatisticQuantity::min
-  );
   auto const load = this_load;
 
   if (target_pole_) {
@@ -453,8 +449,8 @@ void TemperedLB::runLB(LoadType total_load) {
     target_max_load_ = avg;
   }
 
-  // Use an minimal object load on average rank load to load-balance
-  if (avg > min / theContext()->getNumNodes()) {
+  // Use an estimated load-balancing cost on average rank load to load-balance
+  if (avg > getCollectiveEpochCost()) {
     should_lb = max > (run_temperedlb_tolerance + 1.0) * target_max_load_;
   }