max_destinations_ map to optimize conflict computing model

mindspore/ccsrc/backend/optimizer/somas/somas.cc

@@ -911,71 +911,12 @@ void Somas::GenContiguousList(const session::KernelGraph *graph) {
   }
 }
 
-void Somas::PreprocessingConflicts() {
-  // Compute ancestor streams
-  for (auto stream : streams_list_) {
-    stream->ComputeAncestorStreams();
-  }
-
-  // Preset ancestor streams for node
-  for (auto node : nodes_list_) {
-    node->PresetAncestorStreams(streams_list_);
-  }
-
-  // Compute ancestor nodes : needs to be executed in topological order
-  for (auto node : nodes_list_) {
-    node->ComputeAncestorNodes();
-  }
-
-  // Compute MaxDestinationId for between-stream tensors
-  for (auto tensor : tensors_list_) {
-    if (tensor->IsBetweenStreams()) {
-      tensor->ComputeMaxDestinationId();
-    }
-  }
-
-  // Preprocessing for stream groups
-  for (auto group : streams_groups_) {
-    vector<SomasStreamPtr> previous_streams;
-    for (int64_t stream_id : group) {
-      auto it = std::find_if(streams_list_.begin(), streams_list_.end(),
-                             [stream_id](const SomasStreamPtr &stream) { return stream->GetId() == stream_id; });
-      if (it != streams_list_.end()) {
-        for (auto stream : previous_streams) {
-          (*it)->ancestor_streams_group_.insert(stream);
-        }
-        previous_streams.push_back(*it);
-      }
-    }
-  }
-
-  // Atomic: fix any issues on saved lifetimes of tensors
-  for (auto tensor : tensors_list_) {
-    MS_EXCEPTION_IF_NULL(tensor);
-    for (auto node : tensor->destinations_) {
-      MS_EXCEPTION_IF_NULL(node);
-      MS_EXCEPTION_IF_NULL(tensor->GetSourceNode());
-      if (tensor->GetSourceNode()->GetId() > node->GetId()) {
-        tensor->lifetime_.start_ = node->GetId();
-      }
-    }
-    MS_EXCEPTION_IF_NULL(tensor->GetSourceNode());
-    if (tensor->GetSourceNode()->GetId() > tensor->lifetime_.end_) {
-      tensor->lifetime_.end_ = tensor->GetSourceNode()->GetId();
-    }
-  }
-}
-
 void Somas::ComputeConflictPairs() {
   if (tensors_list_.empty()) {
     MS_LOG(INFO) << "No Tensor for Conflict computing";
     return;
   }
 
-  MS_LOG(INFO) << "Start Preprocessing Conflicts";
-  PreprocessingConflicts();
-  MS_LOG(INFO) << "End Preprocessing Conflicts";
-
   MS_LOG(INFO) << "Start Conflict Computing (Bitset Model)";
   auto start_conflict = std::chrono::system_clock::now();
   std::sort(nodes_list_.begin(), nodes_list_.end(), NodeSort);
@@ -1082,6 +1023,11 @@ void Somas::UpdateTensorDestinations() {
       tensor->destinations_.insert(tensor->GetSourceNode());
     }
   }
+
+  // Loop to compute max destinations in each stream
+  for (const auto &tensor : tensors_list_) {
+    tensor->ComputeMaxDestinationId();
+  }
 }
 
 void Somas::ComputeMultiTensorConflicts(const std::vector<SomasTensorPtr> &calc_tensors_list,
@@ -1125,7 +1071,8 @@ void Somas::ComputeOneTensorConflicts(const std::shared_ptr<SomasTensor> &calc_t
 
     bool reuse = true;
     // check calc_tensor's all consumers is target_tensor's source node's dependency or not
-    for (const auto &dst_node : calc_tensor->destinations_) {
+    for (const auto &dst_map : calc_tensor->max_destinations_) {
+      const auto &dst_node = dst_map.second;
       if (nodes_dependency[target_src_node].IsBitTrue(dst_node->GetId()) == false) {
         // calc_tensor's consumer is not in target_tensor's source node's dependency, not sure this consumer is done or
         // not when target_tensor produced

mindspore/ccsrc/backend/optimizer/somas/somas.h

@@ -121,7 +121,6 @@ class Somas {
   SomasTensorPtr CreateGapTensor(size_t gap_tensor_id);
   void GenContiguousList(const session::KernelGraph *graph);
 
-  void PreprocessingConflicts();
   void ComputeConflictPairs();
 
   bool Assign(const session::KernelGraph *graph);

mindspore/ccsrc/backend/optimizer/somas/somas_tensor.cc

@@ -56,10 +56,11 @@ SomasSolverTensorDescPtr SomasTensor::GetSolverTensorDesc() {
 }
 
 void SomasTensor::ComputeMaxDestinationId() {
-  for (SomasStreamPtr stream : destinationStreams_) max_destination_id_[stream] = 0;
-
-  for (SomasNodePtr node : destinations_)
-    if (node->GetId() > max_destination_id_[node->GetStream()]) max_destination_id_[node->GetStream()] = node->GetId();
+  for (const auto &node : destinations_)
+    if (node->GetId() > max_destination_id_[node->GetStream()]) {
+      max_destination_id_[node->GetStream()] = node->GetId();
+      max_destinations_[node->GetStream()] = node;
+    }
 }
 }  // namespace somas
 }  // namespace mindspore

mindspore/ccsrc/backend/optimizer/somas/somas_tensor.h

@@ -82,6 +82,7 @@ class SomasTensor {
   std::set<SomasNodePtr> destinations_;
   std::set<SomasStreamPtr> destinationStreams_;
   unordered_map<SomasStreamPtr, size_t> max_destination_id_;
+  unordered_map<SomasStreamPtr, SomasNodePtr> max_destinations_;
 
   // Constructors/Destructors
   explicit SomasTensor(size_t id, SomasNodePtr source_node, SomasStreamPtr source_stream, size_t real_size,