Convert GradMergeAllReduceOpHandle in GraphToBlock (#46544)

* Convert GradMergeAllReduceOpHandle in GraphToBlock

* Set FLAGS_CONVERT_GRAPH_TO_PROGRAM to False

paddle/fluid/framework/ir/graph_helper.cc

@@ -506,25 +506,27 @@ static OpDesc *ReplaceScaleLossGradOp(const Node &node, OpDesc *desc) {
   return desc;
 }
 
-static void ReplaceAllReduceOp(const Node &node,
+void ReplaceAllReduceOp(const Node &node,
                         proto::BlockDesc *block,
                         std::vector<OpDesc> *ops) {
 #if defined(PADDLE_WITH_NCCL) || defined(PADDLE_WITH_RCCL)
-  ops->emplace_back();
-  auto &desc1 = ops->back();
-  std::string name = "fake_coalesce_" + std::to_string(ops->size());
-  desc1.SetType("check_memory_continue");
-
-  ops->emplace_back();
-  auto &desc2 = ops->back();
-  desc2.SetType("c_allreduce_sum");
-
-  if (node.IsWrappedBy<details::OpHandleBase>()) {
-    details::OpHandleBase &op_handler =
+  bool is_fused = (node.Name() == "fused_all_reduce");
+  details::OpHandleBase &op_handle =
       const_cast<Node *>(&node)->Wrapper<details::OpHandleBase>();
 
-    // set inputs
-    auto in_var_handles = op_handler.Inputs();
+  std::string all_reduce_var_name;
+  // If fused, add check_memory_continue OP to fuse inputs
+  if (is_fused) {
+    all_reduce_var_name = "fake_coalesce_" + std::to_string(ops->size());
+    proto::VarDesc var_desc;
+    var_desc.set_name(all_reduce_var_name);
+    var_desc.mutable_type()->set_type(proto::VarType::LOD_TENSOR);
+    block->mutable_vars()->Add()->CopyFrom(var_desc);
+    VLOG(4) << "add variable for check_memory_continue: "
+            << all_reduce_var_name;
+
+    // get inputs of check_memory_continue
+    auto in_var_handles = op_handle.Inputs();
     std::vector<std::string> in_names;
     for (const auto &in : in_var_handles) {
       if (dynamic_cast<details::DummyVarHandle *>(in) != nullptr) {
@@ -532,47 +534,47 @@ static void ReplaceAllReduceOp(const Node &node,
       }
       in_names.emplace_back(in->Name());
     }
-    desc1.SetInput("X", in_names);
 
-    proto::VarDesc var_desc;
-    var_desc.set_name(name);
-    var_desc.mutable_type()->set_type(proto::VarType::LOD_TENSOR);
-    block->mutable_vars()->Add()->CopyFrom(var_desc);
-    desc1.SetOutput("Out", {name});
-    desc1.SetOutput("XOut", in_names);
-    VLOG(4) << "add variable for check_memory_continue: " << name;
-
-    desc2.SetInput("X", {name});
-    // set outputs
-    auto out_var_handles = op_handler.Outputs();
-    std::vector<std::string> out_names;
-    for (const auto &out : out_var_handles) {
-      if (dynamic_cast<details::DummyVarHandle *>(out) != nullptr) {
-        continue;
-      }
-      out_names.emplace_back(out->Name());
+    ops->emplace_back();
+    OpDesc &fuse_op_desc = ops->back();
+    fuse_op_desc.SetType("check_memory_continue");
+    fuse_op_desc.SetInput("X", in_names);
+    fuse_op_desc.SetOutput("Out", {all_reduce_var_name});
+    fuse_op_desc.SetOutput("XOut", in_names);
+    fuse_op_desc.SetAttr(OpProtoAndCheckerMaker::OpRoleAttrName(),
+                         (static_cast<int>(OpRole::kBackward)));
+  } else {
+    all_reduce_var_name = op_handle.Inputs()[0]->Name();
   }
-    desc2.SetOutput("Out", {name});
+
+  // add c_allreduce_sum OP
+  ops->emplace_back();
+  OpDesc &all_reduce_op_desc = ops->back();
+  all_reduce_op_desc.SetType("c_allreduce_sum");
+  all_reduce_op_desc.SetInput("X", {all_reduce_var_name});
+  all_reduce_op_desc.SetOutput("Out", {all_reduce_var_name});
 
   int ring_id = platform::NCCLCommContext::Instance().GetRingId(
-        dynamic_cast<details::NCCLOpHandleBase *>(&op_handler)->GetComm());
-    desc2.SetAttr("ring_id", ring_id);
-    desc2.SetAttr("use_calc_stream", true);
+      dynamic_cast<details::NCCLOpHandleBase *>(&op_handle)->GetComm());
+  all_reduce_op_desc.SetAttr("ring_id", ring_id);
+  all_reduce_op_desc.SetAttr("use_calc_stream", true);
+  all_reduce_op_desc.SetAttr(OpProtoAndCheckerMaker::OpRoleAttrName(),
+                             (static_cast<int>(OpRole::kBackward)));
 
   // handle grad merge
-    if (dynamic_cast<details::FusedGradMergeAllReduceOpHandle *>(&op_handler)) {
+  if (dynamic_cast<details::FusedGradMergeAllReduceOpHandle *>(&op_handle)) {
     VLOG(4) << "FusedGradMergeAllReduceOpHandle: add cond to c_allreduce_sum";
-      auto cond_name =
-          dynamic_cast<details::FusedGradMergeAllReduceOpHandle *>(&op_handler)
+    const std::string cond_name =
+        dynamic_cast<details::FusedGradMergeAllReduceOpHandle *>(&op_handle)
             ->GradMergeCondName();
-      desc2.SetInput("Cond", {cond_name});
-    }
+    all_reduce_op_desc.SetInput("Cond", {cond_name});
+  } else if (dynamic_cast<details::GradMergeAllReduceOpHandle *>(&op_handle)) {
+    VLOG(4) << "GradMergeAllReduceOpHandle: add cond to c_allreduce_sum";
+    const std::string cond_name =
+        dynamic_cast<details::GradMergeAllReduceOpHandle *>(&op_handle)
+            ->GradMergeCondName();
+    all_reduce_op_desc.SetInput("Cond", {cond_name});
   }
-
-  desc1.SetAttr(OpProtoAndCheckerMaker::OpRoleAttrName(),
-                (static_cast<int>(OpRole::kBackward)));
-  desc2.SetAttr(OpProtoAndCheckerMaker::OpRoleAttrName(),
-                (static_cast<int>(OpRole::kBackward)));
 #else
   PADDLE_THROW(
       platform::errors::Unimplemented("ReplaceAllReduceOp is only implemented "
@@ -629,15 +631,14 @@ static void GetGraphOpDesc(const std::vector<Node *> &nodes,
   for (Node *n : nodes) {
     // if node is not Op, skip
     if (!n->IsOp()) continue;
-
     // create fill_constant op
     if (n->Name() == "scale_loss_grad") {
       VLOG(4) << "convert op node scale_loss_grad to desc fill_constant";
       ops->emplace_back();
       auto &desc = ops->back();
       ReplaceScaleLossGradOp(*n, &desc);
-    } else if (n->Name() == "fused_all_reduce") {
-      VLOG(4) << "convert op node fused_all_reduce to desc c_allreduce_sum";
+    } else if (n->Name() == "allreduce" || n->Name() == "fused_all_reduce") {
+      VLOG(4) << "convert op node " << n->Name() << " to desc c_allreduce_sum";
       ReplaceAllReduceOp(*n, block, ops);
       VLOG(4) << n->ToString();
     } else if (n->Op()) {