Bugfix: Introduced RateAccuracy setting for Drone to conserve CPU at the cost of accuracy

Fixes #151

server/abstractport.cpp

@@ -43,6 +43,7 @@ AbstractPort::AbstractPort(int id, const char *device)
     data_.set_is_exclusive_control(false);
 
     isSendQueueDirty_ = false;
+    rateAccuracy_ = kHighAccuracy;
     linkState_ = OstProto::LinkStateUnknown;
     minPacketSetSize_ = 1;
 
@@ -144,6 +145,17 @@ void AbstractPort::addNote(QString note)
     data_.set_notes(notes.toStdString());
 }
 
+AbstractPort::Accuracy AbstractPort::rateAccuracy()
+{
+    return rateAccuracy_;
+}
+
+bool AbstractPort::setRateAccuracy(Accuracy accuracy)
+{
+    rateAccuracy_ = accuracy;
+    return true;
+}
+
 void AbstractPort::updatePacketList()
 {
     switch(data_.transmit_mode())

server/abstractport.h

@@ -49,6 +49,13 @@ public:
         quint64    txBps;
     };
 
+    enum Accuracy
+    {
+        kHighAccuracy,
+        kMediumAccuracy,
+        kLowAccuracy,
+    };
+
     AbstractPort(int id, const char *device);
     virtual ~AbstractPort();
 
@@ -75,6 +82,9 @@ public:
     bool isDirty() { return isSendQueueDirty_; }
     void setDirty() { isSendQueueDirty_ = true; }
 
+    Accuracy rateAccuracy();
+    virtual bool setRateAccuracy(Accuracy accuracy);
+
     virtual void clearPacketList() = 0;
     virtual void loopNextPacketSet(qint64 size, qint64 repeats,
             long repeatDelaySec, long repeatDelayNsec) = 0;
@@ -106,6 +116,7 @@ protected:
     OstProto::Port          data_;
     OstProto::LinkState     linkState_;
     ulong minPacketSetSize_;
+    Accuracy rateAccuracy_;
 
     quint64 maxStatsValue_;
     struct PortStats    stats_;

server/pcapport.cpp

@@ -167,6 +167,15 @@ void PcapPort::updateNotes()
             arg(notes).toStdString());
 }
 
+bool PcapPort::setRateAccuracy(AbstractPort::Accuracy accuracy)
+{
+    if (transmitter_->setRateAccuracy(accuracy)) {
+        AbstractPort::setRateAccuracy(accuracy);
+        return true;
+    }
+    return false;
+}
+
 PcapPort::PortMonitor::PortMonitor(const char *device, Direction direction,
         AbstractPort::PortStats *stats)
 {
@@ -352,6 +361,26 @@ PcapPort::PortTransmitter::~PortTransmitter()
         pcap_close(handle_);
 }
 
+bool PcapPort::PortTransmitter::setRateAccuracy(
+        AbstractPort::Accuracy accuracy)
+{
+    switch (accuracy) {
+    case kHighAccuracy:
+        udelayFn_ = udelay;
+        qWarning("%s: rate accuracy set to High - busy wait", __FUNCTION__);
+        break;
+    case kLowAccuracy:
+        udelayFn_ = QThread::usleep;
+        qWarning("%s: rate accuracy set to Low - usleep", __FUNCTION__);
+        break;
+    default:
+        qWarning("%s: unsupported rate accuracy value %d", __FUNCTION__, 
+                accuracy);
+        return false;
+    }
+    return true;
+}
+
 void PcapPort::PortTransmitter::clearPacketList()
 {
     Q_ASSERT(!isRunning());
@@ -554,7 +583,7 @@ _restart:
                     long usecs = seq->usecDelay_ + overHead; 
                     if (usecs > 0) 
                     {
-                        udelay(usecs);
+                        (*udelayFn_)(usecs);
                         overHead = 0;
                     }
                     else
@@ -580,7 +609,7 @@ _restart:
 
         if (usecs > 0)
         {
-            udelay(usecs);
+            (*udelayFn_)(usecs);
             overHead = 0;
         }
         else
@@ -656,7 +685,7 @@ int PcapPort::PortTransmitter::sendQueueTransmit(pcap_t *p,
             usec += overHead;
             if (usec > 0)
             {
-                udelay(usec);
+                (*udelayFn_)(usec);
                 overHead = 0;
             }
             else
@@ -685,7 +714,7 @@ int PcapPort::PortTransmitter::sendQueueTransmit(pcap_t *p,
     return 0;
 }
 
-void PcapPort::PortTransmitter::udelay(long usec)
+void PcapPort::PortTransmitter::udelay(unsigned long usec)
 {
 #if defined(Q_OS_WIN32)
     LARGE_INTEGER tgtTicks;

server/pcapport.h

@@ -38,6 +38,8 @@ public:
     virtual bool hasExclusiveControl() { return false; }
     virtual bool setExclusiveControl(bool /*exclusive*/) { return false; }
 
+    virtual bool setRateAccuracy(AbstractPort::Accuracy accuracy); 
+
     virtual void clearPacketList() { 
         transmitter_->clearPacketList();
         setPacketListLoopMode(false, 0, 0);
@@ -102,6 +104,9 @@ protected:
     public:
         PortTransmitter(const char *device);
         ~PortTransmitter();
+
+        bool setRateAccuracy(AbstractPort::Accuracy accuracy); 
+
         void clearPacketList();
         void loopNextPacketSet(qint64 size, qint64 repeats, 
             long repeatDelaySec, long repeatDelayNsec);
@@ -172,7 +177,7 @@ protected:
             long usecDelay_;
         };
 
-        void udelay(long usec);
+        static void udelay(unsigned long usec);
         int sendQueueTransmit(pcap_t *p, pcap_send_queue *queue, long &overHead,
                     int sync);
 
@@ -186,6 +191,8 @@ protected:
         int returnToQIdx_;
         quint64 loopDelay_;
 
+        void (*udelayFn_)(unsigned long);
+
         bool usingInternalStats_;
         AbstractPort::PortStats *stats_;
         bool usingInternalHandle_;

server/portmanager.cpp

@@ -36,12 +36,15 @@ PortManager::PortManager()
     pcap_if_t *deviceList;
     pcap_if_t *device;
     char errbuf[PCAP_ERRBUF_SIZE];
+    AbstractPort::Accuracy txRateAccuracy;
 
     qDebug("Retrieving the device list from the local machine\n"); 
 
     if (pcap_findalldevs(&deviceList, errbuf) == -1)
         qDebug("Error in pcap_findalldevs_ex: %s\n", errbuf);
 
+    txRateAccuracy = rateAccuracy();
+
     for(device = deviceList, i = 0; device != NULL; device = device->next, i++)
     {
         AbstractPort *port;
@@ -81,6 +84,9 @@ PortManager::PortManager()
             continue;
         }
 
+        if (!port->setRateAccuracy(txRateAccuracy))
+            qWarning("failed to set rateAccuracy (%d)", txRateAccuracy);
+
         portList_.append(port);
     }
 
@@ -106,6 +112,21 @@ PortManager* PortManager::instance()
     return instance_;       
 }
 
+AbstractPort::Accuracy PortManager::rateAccuracy()
+{
+    QString rateAccuracy = appSettings->value(kRateAccuracyKey, 
+                                  kRateAccuracyDefaultValue).toString();
+    if (rateAccuracy == "High")
+        return AbstractPort::kHighAccuracy;
+    else if (rateAccuracy == "Low")
+        return AbstractPort::kLowAccuracy;
+    else
+        qWarning("Unsupported RateAccuracy setting - %s", 
+                 qPrintable(rateAccuracy));
+
+    return AbstractPort::kHighAccuracy;
+}
+
 bool PortManager::filterAcceptsPort(const char *name)
 {
     QRegExp pattern;

server/portmanager.h

@@ -35,6 +35,7 @@ public:
     static PortManager* instance();
 
 private:
+    AbstractPort::Accuracy rateAccuracy();
     bool filterAcceptsPort(const char *name);
 
 private:

server/settings.h

@@ -25,6 +25,12 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 
 extern QSettings *appSettings;
 
+//
+// General Section Keys
+//
+const QString kRateAccuracyKey("RateAccuracy");
+const QString kRateAccuracyDefaultValue("High");
+
 //
 // PortList Section Keys
 //