From d564a943ae23df029740dd8a6f09a0bce81de5ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beat=20K=C3=BCng?= <beat-kueng@gmx.net>
Date: Mon, 6 Mar 2017 06:29:35 +0100
Subject: [PATCH] ParameterManager: dynamically set retry timeout based on
 parameter rate

---
 src/FactSystem/ParameterManager.cc | 30 ++++++++++++++++++++++++++----
 src/FactSystem/ParameterManager.h  |  4 ++++
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/src/FactSystem/ParameterManager.cc b/src/FactSystem/ParameterManager.cc
index d81511870..63c17f5b6 100644
--- a/src/FactSystem/ParameterManager.cc
+++ b/src/FactSystem/ParameterManager.cc
@@ -63,6 +63,8 @@ ParameterManager::ParameterManager(Vehicle* vehicle)
 {
     _versionParam = vehicle->firmwarePlugin()->getVersionParam();
 
+    _intervalUpdateTimer.invalidate();
+
     if (_vehicle->isOfflineEditingVehicle()) {
         _loadOfflineEditingParams();
         return;
@@ -221,6 +223,21 @@ void ParameterManager::_parameterUpdate(int vehicleId, int componentId, QString
 
     int readWaitingParamCount = waitingReadParamIndexCount + waitingReadParamNameCount;
     int totalWaitingParamCount = readWaitingParamCount + waitingWriteParamNameCount;
+
+    // dynamically adjust the retry timeout according to the measured incoming parameter rate
+    if (_intervalUpdateTimer.isValid()) {
+        int numParamRead = _totalParamCount - readWaitingParamCount;
+        if (numParamRead > 10) {
+            const int multiplier = 5; // increase the timeout by this factor to account for jitter
+            const int timeout_ms = qMin(3000, (int)(_intervalUpdateTimer.nsecsElapsed() * _maxBatchSize * multiplier / numParamRead / 1000000));
+            qCDebug(ParameterManagerVerbose1Log) << _logVehiclePrefix() << "Setting _waitingParamTimeoutTimer interval:" << timeout_ms;
+            _waitingParamTimeoutTimer.setInterval(timeout_ms);
+        }
+        if (totalWaitingParamCount == 0) {
+            _intervalUpdateTimer.invalidate(); // all params loaded, so don't update the interval anymore
+        }
+    }
+
     if (totalWaitingParamCount) {
         // More params to wait for, restart timer
         _waitingParamTimeoutTimer.start();
@@ -389,6 +406,8 @@ void ParameterManager::refreshAllParameters(uint8_t componentId)
 
     _dataMutex.unlock();
 
+    _intervalUpdateTimer.start();
+
     MAVLinkProtocol* mavlink = qgcApp()->toolbox()->mavlinkProtocol();
     Q_ASSERT(mavlink);
 
@@ -510,9 +529,10 @@ const QMap<int, QMap<QString, QStringList> >& ParameterManager::getGroupMap(void
 void ParameterManager::_waitingParamTimeout(void)
 {
     bool paramsRequested = false;
-    const int maxBatchSize = 10;
     int batchCount = 0;
 
+    _intervalUpdateTimer.invalidate(); // don't update the interval anymore
+
     qCDebug(ParameterManagerLog) << _logVehiclePrefix() << "_waitingParamTimeout";
 
     // First check for any missing parameters from the initial index based load
@@ -524,7 +544,7 @@ void ParameterManager::_waitingParamTimeout(void)
         }
 
         foreach(int paramIndex, _waitingReadParamIndexMap[componentId].keys()) {            
-            if (++batchCount > maxBatchSize) {
+            if (++batchCount > _maxBatchSize) {
                 goto Out;
             }
 
@@ -563,7 +583,7 @@ void ParameterManager::_waitingParamTimeout(void)
                 if (_waitingWriteParamNameMap[componentId][paramName] <= _maxReadWriteRetry) {
                     _writeParameterRaw(componentId, paramName, getParameter(componentId, paramName)->rawValue());
                     qCDebug(ParameterManagerLog) << _logVehiclePrefix(componentId) << "Write resend for (paramName:" << paramName << "retryCount:" << _waitingWriteParamNameMap[componentId][paramName] << ")";
-                    if (++batchCount > maxBatchSize) {
+                    if (++batchCount > _maxBatchSize) {
                         goto Out;
                     }
                 } else {
@@ -585,7 +605,7 @@ void ParameterManager::_waitingParamTimeout(void)
                 if (_waitingReadParamNameMap[componentId][paramName] <= _maxReadWriteRetry) {
                     _readParameterRaw(componentId, paramName, -1);
                     qCDebug(ParameterManagerLog) << _logVehiclePrefix(componentId) << "Read re-request for (paramName:" << paramName << "retryCount:" << _waitingReadParamNameMap[componentId][paramName] << ")";
-                    if (++batchCount > maxBatchSize) {
+                    if (++batchCount > _maxBatchSize) {
                         goto Out;
                     }
                 } else {
@@ -781,6 +801,8 @@ void ParameterManager::_tryCacheHashLoad(int vehicleId, int componentId, QVarian
         });
 
         ani->start(QAbstractAnimation::DeleteWhenStopped);
+
+        _intervalUpdateTimer.invalidate(); // don't change the interval since we loaded the params from cache
     }
 }
 
diff --git a/src/FactSystem/ParameterManager.h b/src/FactSystem/ParameterManager.h
index a2c65c015..e698b6227 100644
--- a/src/FactSystem/ParameterManager.h
+++ b/src/FactSystem/ParameterManager.h
@@ -18,6 +18,7 @@
 #include <QMutex>
 #include <QDir>
 #include <QJsonObject>
+#include <QElapsedTimer>
 
 #include "FactSystem.h"
 #include "MAVLinkProtocol.h"
@@ -196,6 +197,9 @@ private:
     QTimer _initialRequestTimeoutTimer;
     QTimer _waitingParamTimeoutTimer;
     
+    QElapsedTimer _intervalUpdateTimer;        ///< measures the time since refreshAllParameters() was called
+    static constexpr int _maxBatchSize = 10;   ///< maximum number of parameters retry requests at once
+
     QMutex _dataMutex;
     
     static Fact _defaultFact;   ///< Used to return default fact, when parameter not found
-- 
2.22.0