added non-blocking root communicator

src/axom/lumberjack/MPIUtility.cpp

@@ -49,16 +49,49 @@ const char* mpiBlockingReceiveMessages(MPI_Comm comm)
   return charArray;
 }
 
+const char* mpiNonBlockingReceiveMessages(MPI_Comm comm, const int tag)
+{
+  const int mpiTag = (tag == false) ? LJ_TAG : tag;
+  char* charArray = nullptr;
+  int messageSize = -1;
+  MPI_Status mpiStatus;
+
+  // Get size and source of MPI message
+  int mpiFlag = true;
+  MPI_Iprobe(MPI_ANY_SOURCE, tag, comm, &mpiFlag, &mpiStatus);
+
+  if (mpiFlag == true) {
+    MPI_Get_count(&mpiStatus, MPI_CHAR, &messageSize);
+
+    // Setup where to receive the char array
+    charArray = new char[messageSize + 1];
+    charArray[messageSize] = '\0';
+
+    // Receive packed Message
+    MPI_Recv(charArray,
+            messageSize,
+            MPI_CHAR,
+            mpiStatus.MPI_SOURCE,
+            mpiTag,
+            comm,
+            &mpiStatus);
+  }
+
+  return charArray;
+}
+
 void mpiNonBlockingSendMessages(MPI_Comm comm,
                                 int destinationRank,
-                                const char* packedMessagesToBeSent)
+                                const char* packedMessagesToBeSent,
+                                const int tag)
 {
+  const int mpiTag = (tag == false) ? LJ_TAG : tag;
   MPI_Request mpiRequest;
   MPI_Isend(const_cast<char*>(packedMessagesToBeSent),
             strlen(packedMessagesToBeSent),
             MPI_CHAR,
             destinationRank,
-            LJ_TAG,
+            mpiTag,
             comm,
             &mpiRequest);
   MPI_Request_free(&mpiRequest);

src/axom/lumberjack/MPIUtility.hpp

@@ -30,6 +30,16 @@ namespace lumberjack
  */
 const char* mpiBlockingReceiveMessages(MPI_Comm comm);
 
+/*!
+ *****************************************************************************
+ * \brief Receives any Message sent to this rank, if there are any messages 
+ *  that are sent. Returns null if no messages are sent.
+ *
+ * \param [in] comm The MPI Communicator.
+ *****************************************************************************
+ */
+const char* mpiNonBlockingReceiveMessages(MPI_Comm comm, const int tag = 0);
+
 /*!
  *****************************************************************************
  * \brief Sends all Message sent to the given rank.
@@ -40,11 +50,14 @@ const char* mpiBlockingReceiveMessages(MPI_Comm comm);
  * \param [in] destinationRank Where the Message classes is being sent.
  * \param [in,out] packedMessagesToBeSent All of the Message classes to be sent
  *  packed together.
+ * \param [in] tag The MPI tag to use for communication.  When set to zero, 
+ *  MPI communication uses default LJ_Tag.
  *****************************************************************************
  */
 void mpiNonBlockingSendMessages(MPI_Comm comm,
                                 int destinationRank,
-                                const char* packedMessagesToBeSent);
+                                const char* packedMessagesToBeSent,
+                                const int tag = 0);
 }  // end namespace lumberjack
 }  // end namespace axom
 

src/axom/lumberjack/NonBlockingRootCommunicator.cpp

@@ -0,0 +1,91 @@
+// Copyright (c) 2017-2024, Lawrence Livermore National Security, LLC and
+// other Axom Project Developers. See the top-level LICENSE file for details.
+//
+// SPDX-License-Identifier: (BSD-3-Clause)
+
+/*!
+ ******************************************************************************
+ *
+ * \file NonBlockingRootCommunicator.cpp
+ *
+ * \brief Implementation of the NonBlockingRootCommunicator class.
+ *
+ ******************************************************************************
+ */
+
+#include "axom/lumberjack/NonBlockingRootCommunicator.hpp"
+#include "axom/lumberjack/MPIUtility.hpp"
+
+namespace axom
+{
+namespace lumberjack
+{
+void NonBlockingRootCommunicator::initialize(MPI_Comm comm, int ranksLimit)
+{
+  m_mpiComm = comm;
+  MPI_Comm_rank(m_mpiComm, &m_mpiCommRank);
+  MPI_Comm_size(m_mpiComm, &m_mpiCommSize);
+  m_ranksLimit = ranksLimit;
+}
+
+void NonBlockingRootCommunicator::finalize() { }
+
+int NonBlockingRootCommunicator::rank() { return m_mpiCommRank; }
+
+void NonBlockingRootCommunicator::ranksLimit(int value) { m_ranksLimit = value; }
+
+int NonBlockingRootCommunicator::ranksLimit() { return m_ranksLimit; }
+
+int NonBlockingRootCommunicator::numPushesToFlush() { return 1; }
+
+void NonBlockingRootCommunicator::push(const char* packedMessagesToBeSent,
+                            std::vector<const char*>& receivedPackedMessages)
+{
+  constexpr int mpiTag = 32767; 
+  if(m_mpiCommRank == 0)
+  {
+    const char* currPackedMessages = nullptr;
+    bool receive_messages = true;
+    while(receive_messages)
+    {
+      currPackedMessages = mpiNonBlockingReceiveMessages(m_mpiComm, mpiTag);
+
+      if(isPackedMessagesEmpty(currPackedMessages))
+      {
+        if (currPackedMessages == nullptr )
+        {
+          receive_messages = false;
+        } else {
+          delete [] currPackedMessages;
+        }
+
+      }
+      else
+      {
+        receivedPackedMessages.push_back(currPackedMessages);
+      }
+
+      currPackedMessages = nullptr;
+
+    }
+  }
+  else
+  {
+    if(isPackedMessagesEmpty(packedMessagesToBeSent) == false)
+    {
+      mpiNonBlockingSendMessages(m_mpiComm, 0, packedMessagesToBeSent, mpiTag);
+    }
+  }
+}
+
+bool NonBlockingRootCommunicator::isOutputNode()
+{
+  if(m_mpiCommRank == 0)
+  {
+    return true;
+  }
+  return false;
+}
+
+}  // end namespace lumberjack
+}  // end namespace axom

src/axom/lumberjack/NonBlockingRootCommunicator.hpp

@@ -0,0 +1,135 @@
+// Copyright (c) 2017-2024, Lawrence Livermore National Security, LLC and
+// other Axom Project Developers. See the top-level LICENSE file for details.
+//
+// SPDX-License-Identifier: (BSD-3-Clause)
+
+/*!
+ *******************************************************************************
+ * \file NonBlockingRootCommunicator.hpp
+ *
+ * \brief This file contains the class definition of the 
+ *  NonBlockingRootCommunicator.
+ *******************************************************************************
+ */
+
+#ifndef NONBLOCKINGROOTCOMMUNICATOR_HPP
+#define NONBLOCKINGROOTCOMMUNICATOR_HPP
+
+#include "axom/lumberjack/Lumberjack.hpp"
+#include "axom/lumberjack/Communicator.hpp"
+
+namespace axom
+{
+namespace lumberjack
+{
+/*!
+ *******************************************************************************
+ * \class NonBlockingRootCommunicator
+ *
+ * \brief Based off of RootCommunicator. This communicator pushes
+    messages from any rank to root non-collectively, if any messages are sent.
+ *******************************************************************************
+ */
+class NonBlockingRootCommunicator : public axom::lumberjack::Communicator
+{
+public:
+  /*!
+   *****************************************************************************
+   * \brief Called to initialize the Communicator.
+   *
+   * This performs any setup work the Communicator needs before doing any work.
+   * It is required that this is called before using the Communicator.
+   *
+   * \param [in] comm The MPI Communicator
+   * \param [in] ranksLimit Limit on how many ranks are individually tracked per
+   *  Message.
+   *****************************************************************************
+   */
+  void initialize(MPI_Comm comm, int ranksLimit);
+
+  /*!
+   *****************************************************************************
+   * \brief Called to finalize the Communicator.
+   *
+   * This performs any cleanup work the Communicator needs to do before going
+   * away.It is required that this is the last function called by the
+   * Communicator.
+   *****************************************************************************
+   */
+  void finalize();
+
+  /*!
+   *****************************************************************************
+   * \brief Returns the MPI rank of this node
+   *****************************************************************************
+   */
+  int rank();
+
+  /*!
+   *****************************************************************************
+   * \brief Sets the rank limit.
+   *
+   * This is the limit on how many ranks generated a given message are
+   * individually tracked per Message.  After the limit has been reached, only
+   * the Message::rankCount is incremented.
+   *
+   * \param [in] value Limits how many ranks are tracked per Message.
+   *****************************************************************************
+   */
+  void ranksLimit(int value);
+
+  /*!
+   *****************************************************************************
+   * \brief Returns the rank limit.
+   *
+   * This is the limit on how many ranks generated a given message are
+   * individually tracked per Message.  After the limit has been reached, only
+   * the Message::rankCount is incremented.
+   *****************************************************************************
+   */
+  int ranksLimit();
+
+  /*!
+   *****************************************************************************
+   * \brief Function used by the Lumberjack class to indicate how many
+   * individual pushes fully flush all currently held Message classes to the
+   * root node. The Communicator class's tree structure dictates this.
+   *****************************************************************************
+   */
+  int numPushesToFlush();
+
+  /*!
+   *****************************************************************************
+   * \brief This pushes all messages to the root node.
+   *
+   * All messages are pushed to the root node. This is the same as
+   * RootCommunicator::pushMessagesFully for this Communicator.
+   *
+   * \param [in] packedMessagesToBeSent All of this rank's Message classes
+   *  packed into a single buffer.
+   * \param [in,out] receivedPackedMessages Received packed message buffers from
+   *  this nodes children.
+   *****************************************************************************
+   */
+  void push(const char* packedMessagesToBeSent,
+            std::vector<const char*>& receivedPackedMessages);
+
+  /*!
+   *****************************************************************************
+   * \brief Function used by the Lumberjack to indicate whether this node should
+   *  be outputting messages. Only the root node outputs messages.
+   *****************************************************************************
+   */
+  bool isOutputNode();
+
+private:
+  MPI_Comm m_mpiComm;
+  int m_mpiCommRank;
+  int m_mpiCommSize;
+  int m_ranksLimit;
+};
+
+}  // end namespace lumberjack
+}  // end namespace axom
+
+#endif