ENH: print node/topology information in human-readable form at startup

applications/test/parallel-comm2/Test-parallel-comm2.C

@@ -85,7 +85,8 @@ int main(int argc, char *argv[])
 
     if (UPstream::parRun() && optPrintTree)
     {
-        Info<< "comms: " << UPstream::whichCommunication() << endl;
+        Info<< "comms: "
+            << UPstream::whichCommunication(UPstream::worldComm) << nl;
         UPstream::printCommTree(UPstream::commWorld());
     }
 

src/OpenFOAM/db/IOstreams/Pstreams/UPstream.C

@@ -58,6 +58,58 @@ Foam::UPstream::commsTypeNames
 });
 
 
+// * * * * * * * * * * * * * Controls Information  * * * * * * * * * * * * * //
+
+void Foam::UPstream::printNodeCommsControl(Ostream& os)
+{
+    if (UPstream::nodeCommsControl_ > 0)
+    {
+        if (UPstream::usingNodeComms(UPstream::worldComm))
+        {
+            os << "on [";
+        }
+        else
+        {
+            os << "off [";
+        }
+        if (UPstream::nodeCommsMin_ > 2)
+        {
+            os  << "min=" << UPstream::nodeCommsMin_ << ",";
+        }
+        os  << "type=";
+
+        //  1: split by hostname [default]
+        //  2: split by shared
+        //  >=4: (debug/manual) split with given number per node
+        if (UPstream::nodeCommsControl_ >= 4)
+        {
+            os  << UPstream::nodeCommsControl_;
+        }
+        else if (UPstream::nodeCommsControl_ == 2)
+        {
+            os  << "shared";
+        }
+        else
+        {
+            os  << "host";
+        }
+        os  << "]";
+    }
+    else
+    {
+        os  << "disabled";
+    }
+    os  << " (" << UPstream::nProcs(UPstream::worldComm) << " ranks, "
+        << UPstream::numNodes() << " nodes)";
+}
+
+
+void Foam::UPstream::printTopoControl(Ostream& os)
+{
+    os  << "none";
+}
+
+
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 void Foam::UPstream::setParRun(const label nProcs, const bool haveThreads)
@@ -789,6 +841,17 @@ registerOptSwitch
 );
 
 
+int Foam::UPstream::topologyControl_
+(
+    Foam::debug::optimisationSwitch("topoControl", 0)
+);
+registerOptSwitch
+(
+    "topoControl",
+    int,
+    Foam::UPstream::topologyControl_
+);
+
 bool Foam::UPstream::floatTransfer
 (
     Foam::debug::optimisationSwitch("floatTransfer", 0)

src/OpenFOAM/db/IOstreams/Pstreams/UPstream.H

@@ -404,6 +404,15 @@ public:
         //  >= 3 : when there are more than N nodes
         static int nodeCommsMin_;
 
+        //- Selection of topology-aware routines
+        static int topologyControl_;
+
+        //- Test for selection of given topology-aware routine (bitmask)
+        static bool usingTopoControl(int routine = 0) noexcept
+        {
+            return static_cast<bool>(topologyControl_ & routine);
+        }
+
         //- Should compact transfer be used in which floats replace doubles
         //- reducing the bandwidth requirement at the expense of some loss
         //- in accuracy
@@ -757,6 +766,15 @@ public:
         );
 
 
+    // Information
+
+        //- Report the node-communication settings
+        static void printNodeCommsControl(Ostream& os);
+
+        //- Report the topology routines settings
+        static void printTopoControl(Ostream& os);
+
+
     // Requests (non-blocking comms).
     // Pending requests are usually handled as an internal (global) list,
     // since this simplifies the overall tracking and provides a convenient

src/OpenFOAM/global/argList/argList.C

@@ -2094,21 +2094,17 @@ void Foam::argList::parse
                 }
             }
 
-            Info<< "Pstream initialized with:" << nl
-                << "    node communication : ";
-            if (UPstream::nodeCommsControl_ > 0)
+            Info<< "Pstream initialized with:" << nl;
             {
-                Info<< Switch::name(UPstream::usingNodeComms())
-                    << " [min=" << UPstream::nodeCommsMin_
-                    << ", type=" << UPstream::nodeCommsControl_
-                    << "]";
+                Info<< "    node communication : ";
+                UPstream::printNodeCommsControl(Info);
+                Info<< nl;
             }
-            else
             {
-                Info<< "disabled";
+                Info<< "    topology controls  : ";
+                UPstream::printTopoControl(Info);
+                Info<< nl;
             }
-            Info<< " (" << UPstream::nProcs() << " ranks, "
-                << UPstream::numNodes() << " nodes)" << nl;
 
             if (UPstream::floatTransfer)
             {
@@ -2128,7 +2124,7 @@ void Foam::argList::parse
                 const auto& commsType =
                     UPstream::commsTypeNames[UPstream::defaultCommsType];
 
-                Info<< "    nonBlockingExchange: "
+                Info<< "    consensus exchange : "
                     << UPstream::nProcsNonblockingExchange
                     << " (tuning: " << UPstream::tuning_NBX_ << ')' << nl
                     << "    exchange algorithm : "