Merge pull request #46 from Algebraic-Programming/schedule_shrink_updates

updating schedule shrinker

Author: papp-pal-andras

include/osp/bsp/model/BspSchedule.hpp

@@ -836,7 +836,8 @@ class BspSchedule : public IBspSchedule<Graph_t>, public IBspScheduleEval<Graph_
         for (const auto& node : instance->vertices())
             for (const auto &child : instance->getComputationalDag().children(node))
                 if(node_to_processor_assignment[node] != node_to_processor_assignment[child])
-                    comm_phase_empty[node_to_superstep_assignment[child]-1] = false;
+                    for(unsigned offset = 1; offset <= getStaleness(); ++offset)
+                        comm_phase_empty[node_to_superstep_assignment[child] - offset] = false;
 
         std::vector<unsigned> new_step_index(number_of_supersteps);
         unsigned current_index = 0;

include/osp/bsp/model/BspScheduleCS.hpp

@@ -470,29 +470,29 @@ class BspScheduleCS : public BspSchedule<Graph_t> {
 
     virtual void shrinkByMergingSupersteps() override {
 
-        std::vector<unsigned> comm_phase_latest_dependency(this->number_of_supersteps, 0);
+        std::vector<unsigned> superstep_latest_dependency(this->number_of_supersteps, 0);
         std::vector<std::vector<unsigned> > first_at = getFirstPresence();
 
         for (auto const &[key, val] : commSchedule)
             if(this->assignedProcessor(std::get<0>(key)) != std::get<1>(key))
-                comm_phase_latest_dependency[val] = std::max(comm_phase_latest_dependency[val], first_at[std::get<0>(key)][std::get<1>(key)]);
+                superstep_latest_dependency[val] = std::max(superstep_latest_dependency[val], first_at[std::get<0>(key)][std::get<1>(key)]);
 
 
         for (const auto &node : BspSchedule<Graph_t>::instance->getComputationalDag().vertices())
             for (const auto &child : BspSchedule<Graph_t>::instance->getComputationalDag().children(node))
                 if(this->assignedProcessor(node) != this->assignedProcessor(child))
-                    comm_phase_latest_dependency[this->assignedSuperstep(child)] = std::max(comm_phase_latest_dependency[this->assignedSuperstep(child)], first_at[node][this->assignedProcessor(child)]);
+                    superstep_latest_dependency[this->assignedSuperstep(child)] = std::max(superstep_latest_dependency[this->assignedSuperstep(child)], first_at[node][this->assignedProcessor(child)]);
 
-        std::vector<bool> comm_phase_deleted(this->number_of_supersteps, false);
+        std::vector<bool> merge_with_previous(this->number_of_supersteps, false);
         for(unsigned step = this->number_of_supersteps-1; step < this->number_of_supersteps; --step)
         {
             unsigned limit = 0;
             while(step > limit)
             {
-                limit = std::max(limit, comm_phase_latest_dependency[step]);
+                limit = std::max(limit, superstep_latest_dependency[step]);
                 if(step > limit)
                 {
-                    comm_phase_deleted[step] = true;
+                    merge_with_previous[step] = true;
                     --step;
                 }
             }
@@ -502,7 +502,7 @@ class BspScheduleCS : public BspSchedule<Graph_t> {
         unsigned current_index = std::numeric_limits<unsigned>::max();
         for(unsigned step = 0; step < this->number_of_supersteps; ++step)
         {
-            if(!comm_phase_deleted[step])
+            if(!merge_with_previous[step])
                 current_index++;
 
             new_step_index[step] = current_index;

include/osp/bsp/scheduler/LocalSearch/HillClimbing/hill_climbing.hpp

@@ -94,9 +94,6 @@ class HillClimbingScheduler : public ImprovementScheduler<Graph_t> {
     // Create superstep lists (for convenience) for a BSP schedule
     void CreateSupstepLists();
 
-    // Combine subsequent supersteps whenever there is no communication inbetween
-    void RemoveNeedlessSupSteps();
-
     // For memory constraints
     bool use_memory_constraint = false;
     std::vector<std::vector<v_memw_t<Graph_t>>> memory_used;
@@ -178,9 +175,9 @@ RETURN_STATUS HillClimbingScheduler<Graph_t>::improveScheduleWithStepLimit(BspSc
 
 template<typename Graph_t>
 void HillClimbingScheduler<Graph_t>::Init() {
-    if(shrink) // NOTE: shrinking a MaxBspSchedule (without CS) might increase cost
+    if(shrink)
     {
-        RemoveNeedlessSupSteps();
+        schedule->shrinkByMergingSupersteps();
         CreateSupstepLists();
     }
 
@@ -971,37 +968,6 @@ bool HillClimbingScheduler<Graph_t>::violatesMemConstraint(vertex_idx node, unsi
     return false;
 }
 
-template<typename Graph_t>
-void HillClimbingScheduler<Graph_t>::RemoveNeedlessSupSteps() {
-    
-    unsigned current_step = 0;
-
-    unsigned nextBreak = schedule->numberOfSupersteps(), breakAfterNext = schedule->numberOfSupersteps();
-    for (unsigned step = 0; step < schedule->numberOfSupersteps(); ++step) {
-        if (nextBreak == step) {
-            ++current_step;
-            nextBreak = breakAfterNext;
-            if (schedule->getStaleness() == 2)
-                breakAfterNext = schedule->numberOfSupersteps();
-        }
-        for (unsigned proc = 0; proc < schedule->getInstance().getArchitecture().numberOfProcessors(); ++proc)
-            for (const vertex_idx node : supsteplists[step][proc]) {
-                schedule->setAssignedSuperstep(node, current_step);
-                for (const vertex_idx &succ : schedule->getInstance().getComputationalDag().children(node))
-                {
-                    if (schedule->assignedProcessor(node) != schedule->assignedProcessor(succ))
-                    {
-                        nextBreak = std::min(nextBreak, schedule->assignedSuperstep(succ) + 1 - schedule->getStaleness());
-                        if (schedule->getStaleness() == 2)
-                            breakAfterNext = std::min(breakAfterNext, schedule->assignedSuperstep(succ));
-                    }
-                }
-            }
-    }
-
-    schedule->updateNumberOfSupersteps();
-}
-
 template<typename Graph_t>
 void HillClimbingScheduler<Graph_t>::CreateSupstepLists() {
 

tests/CMakeLists.txt

@@ -152,7 +152,7 @@ _add_test( wavefront_scheduler )
 
 _add_test( cuthill_mckee )
 
-_add_test( maxbsp_schedulers )
+_add_test( maxbsp_converter_and_hc )
 
 ## pebbling ILPs
 

tests/maxbsp_schedulers.cpp tests/maxbsp_converter_and_hc.cpptests/maxbsp_schedulers.cpp renamed to tests/maxbsp_converter_and_hc.cpp

@@ -70,7 +70,6 @@ BOOST_AUTO_TEST_CASE(maxbsp_scheduling) {
     // hill climbing
 
     HillClimbingScheduler<graph> HC;
-    HC.setShrink(false);
     HC.improveSchedule(maxbsp);
     BOOST_CHECK(maxbsp.satisfiesPrecedenceConstraints());
     auto cost_hc = maxbsp.computeCosts();