From a56a70b74497b9a5dfc2b587d64e51a14844f3c8 Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@esi-group.com>
Date: Fri, 29 Sep 2017 19:35:08 +0200
Subject: [PATCH] ENH: adjust infoSwitch to report host subscription (related
 to #531)

- this compact form shows the subscription per host in the unsorted
  mpi order

      nProcs : 18
      Hosts  :
      (
          (node1 6)
          (node2 8)
          (node3 4)
      )

  This provides a succinct overview of which hosts have been
  subscribed or oversubscribed.

- The longer list of "slave.pid" ... remains available on the
  InfoSwitch 'writeHosts'
---
 etc/controlDict                       | 13 +++---
 src/OpenFOAM/global/argList/argList.C | 62 ++++++++++++++++++++++++++-
 2 files changed, 68 insertions(+), 7 deletions(-)

diff --git a/etc/controlDict b/etc/controlDict
index 77a630c3fb..37ebba2b46 100644
--- a/etc/controlDict
+++ b/etc/controlDict
@@ -38,21 +38,24 @@ InfoSwitches
     // The default ASCII write precision
     writePrecision  6;
 
-    // Enable job info
-    writeJobInfo    0;
-
     writeDictionaries 0;
     writeOptionalEntries 0;
 
     // Write lagrangian "positions" file in v1706 format (at earlier)
     writeLagrangianPositions 0;
 
-    // Report list of slaves/pids used (parallel)
-    writeSlaves     1;
+    // Report hosts used (parallel)
+    // - 0 = none
+    // - 1 = per-host-count, but unsorted
+    // - 2 = long output of "slave.pid" ...
+    writeHosts      1;
 
     // Report list of roots used (parallel)
     writeRoots      1;
 
+    // Enable job info
+    writeJobInfo    0;
+
     // Allow profiling
     allowProfiling  1;
 
diff --git a/src/OpenFOAM/global/argList/argList.C b/src/OpenFOAM/global/argList/argList.C
index 20d4bffbc7..d832a6d7f2 100644
--- a/src/OpenFOAM/global/argList/argList.C
+++ b/src/OpenFOAM/global/argList/argList.C
@@ -102,6 +102,53 @@ Foam::argList::initValidTables::initValidTables()
 
 Foam::argList::initValidTables dummyInitValidTables;
 
+// * * * * * * * * * * * * * * * Local Functions * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Counted per machine name
+// Does not include any sorting since we wish to know the ordering according to
+// mpi rank.
+//
+// Always include the master too.
+// This provides a better overview of the subscription
+static void printHostsSubscription(const UList<string>& slaveProcs)
+{
+    Info<< "Hosts  :" << nl << "(" << nl;
+
+    std::string prev = hostName();
+    int count = 1;
+
+    for (const auto& str : slaveProcs)
+    {
+        const auto dot = str.rfind('.');
+        const std::string curr(std::move(str.substr(0, dot)));
+
+        if (prev != curr)
+        {
+            if (count)
+            {
+                // Finish previous
+                Info<<"    (" << prev.c_str() << " " << count << ")" << nl;
+                count = 0;
+            }
+
+            prev = std::move(curr);
+        }
+        ++count;
+    }
+
+    if (count)
+    {
+        // Finished last one
+        Info<<"    (" << prev.c_str() << " " << count << ")" << nl;
+    }
+
+    Info<< ")" << nl;
+}
+
+}
 
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
 
@@ -931,6 +978,7 @@ void Foam::argList::parse
     }
 
     stringList slaveProcs;
+    const int writeHostsSwitch = debug::infoSwitch("writeHosts", 1);
 
     // Collect slave machine/pid, and check that the build is identical
     if (parRunControl_.parRun())
@@ -981,8 +1029,9 @@ void Foam::argList::parse
     // Keep or discard slave and root information for reporting:
     if (Pstream::master() && parRunControl_.parRun())
     {
-        if (!debug::infoSwitch("writeSlaves", 1))
+        if (!writeHostsSwitch)
         {
+            // Clear here to ensures it doesn't show in the jobInfo
             slaveProcs.clear();
         }
         if (!debug::infoSwitch("writeRoots", 1))
@@ -1000,7 +1049,16 @@ void Foam::argList::parse
         {
             if (slaveProcs.size())
             {
-                Info<< "Slaves : " << slaveProcs << nl;
+                if (writeHostsSwitch == 1)
+                {
+                    // Compact output (see etc/controlDict)
+                    printHostsSubscription(slaveProcs);
+                }
+                else
+                {
+                    // Full output of "slave.pid"
+                    Info<< "Slaves : " << slaveProcs << nl;
+                }
             }
             if (roots.size())
             {