From 30c8f462c35d8985f5d77bc1ccd103b07592b58c Mon Sep 17 00:00:00 2001
From: Volker Fischer <corrados@users.noreply.github.com>
Date: Tue, 4 Aug 2020 16:43:32 +0200
Subject: [PATCH] add multithreading CONFIG parameter and use thread
 synchronization

---
 Jamulus.pro    |  8 +++++++-
 src/server.cpp | 45 ++++++++++++++++++++-------------------------
 src/server.h   | 23 ++++-------------------
 3 files changed, 31 insertions(+), 45 deletions(-)

diff --git a/Jamulus.pro b/Jamulus.pro
index 2ae267dc..7317fd9b 100755
--- a/Jamulus.pro
+++ b/Jamulus.pro
@@ -6,12 +6,18 @@ contains(CONFIG, "noupcasename") {
     TARGET = jamulus
 }
 
+# support multi-threading with OMP if requested
+contains(CONFIG, "multithreading") {
+    message(Multithreading in the server is enabled.)
+    DEFINES += USE_MULTITHREADING
+    QT += concurrent
+}
+
 CONFIG += qt \
     thread \
     release
 
 QT += network \
-    concurrent \
     xml
 
 contains(CONFIG, "headless") {
diff --git a/src/server.cpp b/src/server.cpp
index 0ca900ba..92ea936e 100755
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -979,6 +979,10 @@ static CTimingMeas JitterMeas ( 1000, "test2.dat" ); JitterMeas.Measure(); // TE
 
 
     // Process data ------------------------------------------------------------
+#ifdef USE_MULTITHREADING
+    QFutureSynchronizer<void> FutureSynchronizer;
+#endif
+
     // Check if at least one client is connected. If not, stop server until
     // one client is connected.
     if ( iNumClients > 0 )
@@ -1055,35 +1059,26 @@ static CTimingMeas JitterMeas ( 1000, "test2.dat" ); JitterMeas.Measure(); // TE
                 }
             }
 
-// TEST
-QFuture<void> future = QtConcurrent::run ( this, &CServer::MixEncodeTransmitData,
-                                           i,
-                                           iCurChanID,
-                                           pCurOpusEncoder,
-                                           iClientFrameSizeSamples,
-                                           iNumClients );
-
-
             // generate a separate mix for each channel, OPUS encode the
-            // audio data and transmit the network packet
-/*
-            MixEncodeTransmitData ( vecvecsData,
-                                    vecvecdGains[i],
-                                    vecvecdPannings[i],
-                                    vecNumAudioChannels,
-                                    vecvecsIntermediateProcBuf[i],
-                                    vecvecsSendData[i],
-                                    vecvecbyCodedData[i],
-                                    vecChannels[iCurChanID],
-                                    DoubleFrameSizeConvBufOut[iCurChanID],
-                                    vecUseDoubleSysFraSizeConvBuf[i],
-                                    vecNumFrameSizeConvBlocks[i],
+            // audio data and transmit the network packet (note that if
+            // multithreading is enabled, the work is distributed over
+            // all available processor cores)
+#ifdef USE_MULTITHREADING
+            // by using the future synchronizer we make sure that all
+            // threads are done when we leave the timer callback function
+            FutureSynchronizer.addFuture ( QtConcurrent::run ( this, &CServer::MixEncodeTransmitData,
+                                                               i,
+                                                               iCurChanID,
+                                                               pCurOpusEncoder,
+                                                               iClientFrameSizeSamples,
+                                                               iNumClients ) );
+#else
+            MixEncodeTransmitData ( i,
+                                    iCurChanID,
                                     pCurOpusEncoder,
-                                    iCeltNumCodedBytes,
                                     iClientFrameSizeSamples,
-                                    iCurNumAudChan,
                                     iNumClients );
-*/
+#endif
         }
     }
     else
diff --git a/src/server.h b/src/server.h
index c04e8f8e..56bd4443 100755
--- a/src/server.h
+++ b/src/server.h
@@ -29,8 +29,11 @@
 #include <QDateTime>
 #include <QHostAddress>
 #include <QFileInfo>
-#include <QtConcurrent>
 #include <algorithm>
+#ifdef USE_MULTITHREADING
+# include <QtConcurrent>
+# include <QFutureSynchronizer>
+#endif
 #ifdef USE_OPUS_SHARED_LIB
 # include "opus/opus_custom.h"
 #else
@@ -302,24 +305,6 @@ protected:
 
     void WriteHTMLChannelList();
 
-/*
-    void MixEncodeTransmitData ( const CVector<CVector<int16_t> >& vecvecsData,
-                                 const CVector<double>&            vecdGains,
-                                 const CVector<double>&            vecdPannings,
-                                 const CVector<int>&               vecNumAudioChannels,
-                                 CVector<double>&                  vecdIntermProcBuf,
-                                 CVector<int16_t>&                 vecsSendData,
-                                 CVector<uint8_t>&                 vecbyCodedData,
-                                 CChannel&                         Channel,
-                                 CConvBuf<int16_t>&                DoubleFrameSizeConvBufOut,
-                                 const int                         iUseDoubleSysFraSizeConvBuf,
-                                 const int                         iNumFrameSizeConvBlocks,
-                                 OpusCustomEncoder*                pCurOpusEncoder,
-                                 const int                         iCeltNumCodedBytes,
-                                 const int                         iClientFrameSizeSamples,
-                                 const int                         iCurNumAudChan,
-                                 const int                         iNumClients );
-*/
 
 // TEST
 void MixEncodeTransmitData ( const int          iIdx,