Ref T270, performance improvement by keeping less elevations cached

Rational: the idea was to keep track of ground elevations of all aircraft and hence using them for other aircraft on ground. But the "hit" ratio is bad, so we only keep a small number of elevations ("the last ones") and use those. The size of the cache is dynamically adjusted. Not moving aircraft are still found in that much smaller list.

src/blackcore/simulator.cpp

@@ -109,7 +109,12 @@ namespace BlackCore
     void ISimulator::rememberElevationAndCG(const CCallsign &callsign, const Geo::CElevationPlane &elevation, const CLength &cg)
     {
         if (callsign.isEmpty()) { return; }
-        if (!elevation.isNull()) { this->rememberGroundElevation(elevation); }
+        if (!elevation.isNull())
+        {
+            const int aircraftCount = this->getAircraftInRangeCount();
+            this->setRememberMaxElevations(aircraftCount * 3); // at least 3 elevations per aircraft, even better as not all are requesting elevations
+            this->rememberGroundElevation(elevation);
+        }
         if (!cg.isNull() && !this->hasSameCG(cg, callsign)) { this->insertCG(cg, callsign); }
     }
 
@@ -120,9 +125,11 @@ namespace BlackCore
         {
             // decouple, follow up of signal can include unloading
             // simulator so this should happen strictly asyncronously (which is like forcing Qt::QueuedConnection)
+            QPointer<ISimulator> myself(this);
             QTimer::singleShot(0, this, [ = ]
             {
-                emit this->simulatorStatusChanged(newStatus);
+                if (!myself) { return; }
+                emit myself->simulatorStatusChanged(newStatus);
             });
         }
     }

src/blackmisc/simulation/simulationenvironmentprovider.cpp

@@ -20,6 +20,7 @@ namespace BlackMisc
         bool ISimulationEnvironmentProvider::rememberGroundElevation(const ICoordinateGeodetic &elevationCoordinate, const CLength &epsilon)
         {
             {
+                // no 2nd elevation nearby
                 QReadLocker l(&m_lockElvCoordinates);
                 if (m_elvCoordinates.containsObjectInRange(elevationCoordinate, minRange(epsilon))) { return false; }
             }
@@ -28,7 +29,7 @@ namespace BlackMisc
                 // * we assume we find them faster
                 // * and need the more frequently (the recent ones)
                 QWriteLocker l(&m_lockElvCoordinates);
-                if (m_elvCoordinates.size() > MaxElevations) { m_elvCoordinates.pop_back(); }
+                if (m_elvCoordinates.size() > m_maxElevations) { m_elvCoordinates.pop_back(); }
                 m_elvCoordinates.push_front(elevationCoordinate);
             }
             return true;
@@ -76,9 +77,18 @@ namespace BlackMisc
             return m_elvCoordinates;
         }
 
+        CCoordinateGeodeticList ISimulationEnvironmentProvider::getElevationCoordinates(int &maxRemembered) const
+        {
+            QReadLocker l(&m_lockElvCoordinates);
+            maxRemembered = m_maxElevations;
+            return m_elvCoordinates;
+        }
+
         int ISimulationEnvironmentProvider::cleanUpElevations(const ICoordinateGeodetic &referenceCoordinate, int maxNumber)
         {
-            CCoordinateGeodeticList coordinates(this->getElevationCoordinates());
+            int currentMax;
+            CCoordinateGeodeticList coordinates(this->getElevationCoordinates(currentMax));
+            if (maxNumber < 0) { maxNumber = currentMax; }
             const int size = coordinates.size();
             if (size <= maxNumber) { return 0; }
             coordinates.sortByEuclideanDistanceSquared(referenceCoordinate);
@@ -168,6 +178,19 @@ namespace BlackMisc
             return m_cgs[callsign] == cg;
         }
 
+        int ISimulationEnvironmentProvider::setRememberMaxElevations(int max)
+        {
+            QWriteLocker l(&m_lockElvCoordinates);
+            m_maxElevations = qMax(max, 50);
+            return m_maxElevations;
+        }
+
+        int ISimulationEnvironmentProvider::getRememberMaxElevations() const
+        {
+            QReadLocker l(&m_lockElvCoordinates);
+            return m_maxElevations;
+        }
+
         ISimulationEnvironmentProvider::ISimulationEnvironmentProvider(const CSimulatorPluginInfo &pluginInfo) : m_simulatorPluginInfo(pluginInfo)
         { }
 

src/blackmisc/simulation/simulationenvironmentprovider.h

@@ -33,7 +33,6 @@ namespace BlackMisc
         {
         public:
             //! All remembered coordiantes
-            //! \remark might be a relatively large list
             //! \threadsafe
             Geo::CCoordinateGeodeticList getElevationCoordinates() const;
 
@@ -77,10 +76,22 @@ namespace BlackMisc
             //! \threadsafe
             bool hasSameCG(const PhysicalQuantities::CLength &cg, const Aviation::CCallsign &callsign) const;
 
+            //! Set number of elevations kept
+            //! \threadsafe
+            int setRememberMaxElevations(int max);
+
+            //! Get number of max. number of elevations
+            //! \threadsafe
+            int getRememberMaxElevations() const;
+
         protected:
             //! Ctor
             ISimulationEnvironmentProvider(const CSimulatorPluginInfo &pluginInfo);
 
+            //! All remembered coordiantes plus max remembered situations
+            //! \threadsafe
+            Geo::CCoordinateGeodeticList getElevationCoordinates(int &maxRemembered) const;
+
             //! New plugin info and default model
             //! \remark normally only used by emulated driver
             //! \threadsafe
@@ -107,7 +118,7 @@ namespace BlackMisc
 
             //! Only keep closest ones
             //! \threadsafe
-            int cleanUpElevations(const Geo::ICoordinateGeodetic &referenceCoordinate, int maxNumber = MaxElevations);
+            int cleanUpElevations(const Geo::ICoordinateGeodetic &referenceCoordinate, int maxNumber = -1);
 
             //! Remember a given elevation
             //! \threadsafe
@@ -129,9 +140,8 @@ namespace BlackMisc
             //! Min.range considered as single point
             static PhysicalQuantities::CLength minRange(const PhysicalQuantities::CLength &range);
 
-            static constexpr int MaxElevations = 1000;  //!< How many elevations we keep
-
         private:
+            int m_maxElevations = 100; //!< How many elevations we keep
             CAircraftModel m_defaultModel; //!< default model
             CSimulatorPluginInfo m_simulatorPluginInfo; //!< info object
             Geo::CCoordinateGeodeticList m_elvCoordinates;