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Qt6 Windows slower than Qt6 Ubuntu

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ubuntuwindows 10 instmsvcgccqt6
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  • JonBJ JonB

    @Joe-von-Habsburg
    I would guess you need to not delete it yourself now (_reply->deleteLater()) since it is being auto-deleted on QNetworkReply::finished?

    However if it is being auto-deleted on finished then, because you do _loop.exec(); which waits for finished I would guess you can no longer do _reply->readAll() after the loop, that sounds like crash. You could instead do your data reading inside the loop instead of afterwards.

    I really don't know, and have never used any of this stuff :) It was suggestions for narrowing down where the "leakage" might be. But you need someone else if you need someone who truly knows about it.

    J Offline
    J Offline
    Joe von Habsburg
    wrote on last edited by
    #30

    @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

    You could instead do your data reading inside the loop instead of afterwards.

    can you give me code example ?

    @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

    But you need someone else if you need someone who truly knows about it.

    Yes but who will be :D

    JonBJ 1 Reply Last reply
    0
    • J Joe von Habsburg

      @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

      You could instead do your data reading inside the loop instead of afterwards.

      can you give me code example ?

      @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

      But you need someone else if you need someone who truly knows about it.

      Yes but who will be :D

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #31

      @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

      can you give me code example ?

      loop.exec() is just a convenience, which blocks till finished(), making your call "synchronous". Instead you can deal with all the data which arrives when it arrives (instead of after finished()) by attaching a slot to _reply->readyRead() signal.

      Of course, if you remove _loop.exec() from getData() it will exit while network stuff is still going on, you must not have local variables which go out of scope. You will have to do quite a bit of code reorganizing. And it might be to no avail, I don't know what it will reveal or whether it will solve anything.

      J 1 Reply Last reply
      0
      • JonBJ JonB

        @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

        can you give me code example ?

        loop.exec() is just a convenience, which blocks till finished(), making your call "synchronous". Instead you can deal with all the data which arrives when it arrives (instead of after finished()) by attaching a slot to _reply->readyRead() signal.

        Of course, if you remove _loop.exec() from getData() it will exit while network stuff is still going on, you must not have local variables which go out of scope. You will have to do quite a bit of code reorganizing. And it might be to no avail, I don't know what it will reveal or whether it will solve anything.

        J Offline
        J Offline
        Joe von Habsburg
        wrote on last edited by Joe von Habsburg
        #32

        @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

        loop.exec() is just a convenience, which blocks till finished(), making your call "synchronous". Instead you can deal with all the data which arrives when it arrives (instead of after finished()) by attaching a slot to _reply->readyRead() signal.

        I changed my code.

        void DataReceiver::start()
        {
            if(!_takeData)
                return;
        
            QDateTime time1 = QDateTime::currentDateTime();
            getDataSample(); //_sample = getData(54664);
            QDateTime time3 = QDateTime::currentDateTime();
            if(_takeIQData)
                getDataIQ(); //_iq = getData(54665);
            QDateTime time2 = QDateTime::currentDateTime();
            qDebug() << "sample : " << time3 - time1 << " iq : " << time2 - time3 << "time : " << time2 - time1;
        }
        
        void DataReceiver::getDataSample()
        {
            QString url = QString("http://localhost:%1/sample").arg(54664);
            QUrl _apiUrl(url);
            QNetworkRequest _request(_apiUrl);
            _replySample = _managerSample.get(_request);
            connect(_replySample, &QNetworkReply::readyRead, this, &DataReceiver::readSample);
        }
        
        void DataReceiver::getDataIQ()
        {
            QString url = QString("http://localhost:%1/sample").arg(54665);
            QUrl _apiUrl(url);
            QNetworkRequest _request(_apiUrl);
            _replyIQ = _managerIQ.get(_request);
            connect(_replyIQ, &QNetworkReply::readyRead, this, &DataReceiver::readIQ);
        }
        
        void DataReceiver::readSample()
        {
            _sample = _replySample->readAll();
            _replySample->deleteLater();
            if(!_takeIQData){
                emit sendData(_sample, _iq);
                _sample.clear();
                _iq.clear();
                start();
            }
        
        }
        
        void DataReceiver::readIQ()
        {
            _iq = _replyIQ->readAll();
            _replyIQ->deleteLater();
            if(_takeIQData){
                emit sendData(_sample, _iq);
                _sample.clear();
                _iq.clear();
                start();
            }
        }
        

        After a while crashing :(

        J 1 Reply Last reply
        0
        • J Joe von Habsburg

          @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

          loop.exec() is just a convenience, which blocks till finished(), making your call "synchronous". Instead you can deal with all the data which arrives when it arrives (instead of after finished()) by attaching a slot to _reply->readyRead() signal.

          I changed my code.

          void DataReceiver::start()
          {
              if(!_takeData)
                  return;
          
              QDateTime time1 = QDateTime::currentDateTime();
              getDataSample(); //_sample = getData(54664);
              QDateTime time3 = QDateTime::currentDateTime();
              if(_takeIQData)
                  getDataIQ(); //_iq = getData(54665);
              QDateTime time2 = QDateTime::currentDateTime();
              qDebug() << "sample : " << time3 - time1 << " iq : " << time2 - time3 << "time : " << time2 - time1;
          }
          
          void DataReceiver::getDataSample()
          {
              QString url = QString("http://localhost:%1/sample").arg(54664);
              QUrl _apiUrl(url);
              QNetworkRequest _request(_apiUrl);
              _replySample = _managerSample.get(_request);
              connect(_replySample, &QNetworkReply::readyRead, this, &DataReceiver::readSample);
          }
          
          void DataReceiver::getDataIQ()
          {
              QString url = QString("http://localhost:%1/sample").arg(54665);
              QUrl _apiUrl(url);
              QNetworkRequest _request(_apiUrl);
              _replyIQ = _managerIQ.get(_request);
              connect(_replyIQ, &QNetworkReply::readyRead, this, &DataReceiver::readIQ);
          }
          
          void DataReceiver::readSample()
          {
              _sample = _replySample->readAll();
              _replySample->deleteLater();
              if(!_takeIQData){
                  emit sendData(_sample, _iq);
                  _sample.clear();
                  _iq.clear();
                  start();
              }
          
          }
          
          void DataReceiver::readIQ()
          {
              _iq = _replyIQ->readAll();
              _replyIQ->deleteLater();
              if(_takeIQData){
                  emit sendData(_sample, _iq);
                  _sample.clear();
                  _iq.clear();
                  start();
              }
          }
          

          After a while crashing :(

          J Offline
          J Offline
          Joe von Habsburg
          wrote on last edited by
          #33

          @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

          After a while crashing :(

          I found the reason. Because readReady() sometimes receives incomplete data.

          jsulmJ JonBJ 2 Replies Last reply
          0
          • J Joe von Habsburg

            @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

            After a while crashing :(

            I found the reason. Because readReady() sometimes receives incomplete data.

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #34

            @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

            sometimes receives incomplete data

            Yes, because there is no guarantee that you get all data in one piece. That's why you need to buffer incoming data until you received a whole package of data.

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            Christian EhrlicherC J 2 Replies Last reply
            1
            • jsulmJ jsulm

              @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

              sometimes receives incomplete data

              Yes, because there is no guarantee that you get all data in one piece. That's why you need to buffer incoming data until you received a whole package of data.

              Christian EhrlicherC Offline
              Christian EhrlicherC Offline
              Christian Ehrlicher
              Lifetime Qt Champion
              wrote on last edited by
              #35

              @jsulm... or use the requestFinished signal 🙂

              Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
              Visit the Qt Academy at https://academy.qt.io/catalog

              1 Reply Last reply
              2
              • jsulmJ jsulm

                @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                sometimes receives incomplete data

                Yes, because there is no guarantee that you get all data in one piece. That's why you need to buffer incoming data until you received a whole package of data.

                J Offline
                J Offline
                Joe von Habsburg
                wrote on last edited by Joe von Habsburg
                #36

                @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                Yes, because there is no guarantee that you get all data in one piece. That's why you need to buffer incoming data until you received a whole package of data.

                Yes, I try downloadProgress signal like that:

                void DataReceiver::downloadProgressSample(qint64 bytesReceived, qint64 bytesTotal)
                {
                    if(bytesReceived == bytesTotal){
                        _isSampleOk = true;
                        _sampleLen = bytesReceived;
                    }
                    else{
                        _isSampleOk = false;
                        _sampleLen = 0;
                    }
                }
                

                but so many times, my QByteArray's length and bytesReceived are not equal.... and my program slowing for that.

                @Christian-Ehrlicher said in Qt6 Windows slower than Qt6 Ubuntu:

                or use the requestFinished signal

                I could not see requestFinished signal on documentation. Do you mean say finished signal ?

                jsulmJ JonBJ 2 Replies Last reply
                0
                • J Joe von Habsburg

                  @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                  After a while crashing :(

                  I found the reason. Because readReady() sometimes receives incomplete data.

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #37

                  @Joe-von-Habsburg
                  Exactly as my colleagues have replied above for readyRead().

                  If you are still pursuing the difference in memory usage you report. A couple of points about your code:

                  You have a couple of calls to getData() inside some loop, while (_takeData). Your getData() uses (or used to use, you may have changed that now) _reply->deleteLater(). Although you have a QEventLoop::exec() call, which will allow signals/slots to flow, this is not the top-level Qt event loop. I believe deleteLater() causes deferred deletes, meaning that the memory is not actually released until the top-level event loop is re-entered. You should not use a while loop like this for your tests: allow the top-level Qt event loop to be re-entered.

                  getData() returns a QByteArray. We do not know what your code does with that result: for all we know you retain that somewhere, and that would eat up memory.

                  To investigate properly you should produce a minimal reproducible example with "good" code, to be sure what you are looking at.

                  1 Reply Last reply
                  0
                  • J Joe von Habsburg

                    @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                    Yes, because there is no guarantee that you get all data in one piece. That's why you need to buffer incoming data until you received a whole package of data.

                    Yes, I try downloadProgress signal like that:

                    void DataReceiver::downloadProgressSample(qint64 bytesReceived, qint64 bytesTotal)
                    {
                        if(bytesReceived == bytesTotal){
                            _isSampleOk = true;
                            _sampleLen = bytesReceived;
                        }
                        else{
                            _isSampleOk = false;
                            _sampleLen = 0;
                        }
                    }
                    

                    but so many times, my QByteArray's length and bytesReceived are not equal.... and my program slowing for that.

                    @Christian-Ehrlicher said in Qt6 Windows slower than Qt6 Ubuntu:

                    or use the requestFinished signal

                    I could not see requestFinished signal on documentation. Do you mean say finished signal ?

                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #38

                    @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                    Yes, I try downloadProgress signal like that

                    What does this have to do with buffering incoming data?
                    To get a simpler solution follow @Christian-Ehrlicher suggestion.

                    https://forum.qt.io/topic/113070/qt-code-of-conduct

                    1 Reply Last reply
                    0
                    • J Joe von Habsburg

                      @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                      Yes, because there is no guarantee that you get all data in one piece. That's why you need to buffer incoming data until you received a whole package of data.

                      Yes, I try downloadProgress signal like that:

                      void DataReceiver::downloadProgressSample(qint64 bytesReceived, qint64 bytesTotal)
                      {
                          if(bytesReceived == bytesTotal){
                              _isSampleOk = true;
                              _sampleLen = bytesReceived;
                          }
                          else{
                              _isSampleOk = false;
                              _sampleLen = 0;
                          }
                      }
                      

                      but so many times, my QByteArray's length and bytesReceived are not equal.... and my program slowing for that.

                      @Christian-Ehrlicher said in Qt6 Windows slower than Qt6 Ubuntu:

                      or use the requestFinished signal

                      I could not see requestFinished signal on documentation. Do you mean say finished signal ?

                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by JonB
                      #39

                      @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                      but so many times, my QByteArray's length and bytesReceived are not equal.... and my program slowing for that.

                      I don't understand your point or question here? If you readyRead() as you go along or use QNetworkReply::downloadProgress() you will (almost certainly) see data arrive in "chunks", i.e. multiple calls until all the data is received. That is how the data is being transmitted, and is quite normal/expected.

                      As I wrote earlier, if you do not want to handle partial data as it arrives, and are using reply auto-delete so you cannot access it after it has finished, you can place a slot on QNetworkReply::finished and readAll() the data there in one go, before allowing the reply to be deleted.

                      J 1 Reply Last reply
                      1
                      • JonBJ JonB

                        @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                        but so many times, my QByteArray's length and bytesReceived are not equal.... and my program slowing for that.

                        I don't understand your point or question here? If you readyRead() as you go along or use QNetworkReply::downloadProgress() you will (almost certainly) see data arrive in "chunks", i.e. multiple calls until all the data is received. That is how the data is being transmitted, and is quite normal/expected.

                        As I wrote earlier, if you do not want to handle partial data as it arrives, and are using reply auto-delete so you cannot access it after it has finished, you can place a slot on QNetworkReply::finished and readAll() the data there in one go, before allowing the reply to be deleted.

                        J Offline
                        J Offline
                        Joe von Habsburg
                        wrote on last edited by
                        #40

                        @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                        What does this have to do with buffering incoming data?
                        To get a simpler solution follow @Christian-Ehrlicher suggestion.

                        I could not see requestFinished signal on documentation. Do you mean say "finished" signal ?

                        @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                        don't understand your point or question here?

                        My question is that. if I use "finished" signal memory leak.

                        @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                        _reply->readyRead()

                        You suggested to me "readyRead" signal but now, I could not readyAll because, incomplated data is received.

                        For example, data's size must be 350000, but i receive 348000 or less. As a result of for that I crashed.

                        @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                        QNetworkReply::downloadProgress()

                        I try check will have arrived data size use with "downloadProgress" signal and my QByteArray data size is equal ? but so many times thay are not.

                        How can I wait all data complate without use "finished" signal because memory leak?

                        @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                        As I wrote earlier, if you do not want to handle partial data as it arrives, and are using reply auto-delete so you cannot access it after it has finished, you can place a slot on QNetworkReply::finished and readAll() the data there in one go, before allowing the reply to be deleted.

                        I don't understand. Can you give me code example ?

                        jsulmJ JonBJ 2 Replies Last reply
                        0
                        • J Joe von Habsburg

                          @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                          What does this have to do with buffering incoming data?
                          To get a simpler solution follow @Christian-Ehrlicher suggestion.

                          I could not see requestFinished signal on documentation. Do you mean say "finished" signal ?

                          @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                          don't understand your point or question here?

                          My question is that. if I use "finished" signal memory leak.

                          @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                          _reply->readyRead()

                          You suggested to me "readyRead" signal but now, I could not readyAll because, incomplated data is received.

                          For example, data's size must be 350000, but i receive 348000 or less. As a result of for that I crashed.

                          @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                          QNetworkReply::downloadProgress()

                          I try check will have arrived data size use with "downloadProgress" signal and my QByteArray data size is equal ? but so many times thay are not.

                          How can I wait all data complate without use "finished" signal because memory leak?

                          @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                          As I wrote earlier, if you do not want to handle partial data as it arrives, and are using reply auto-delete so you cannot access it after it has finished, you can place a slot on QNetworkReply::finished and readAll() the data there in one go, before allowing the reply to be deleted.

                          I don't understand. Can you give me code example ?

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #41

                          @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                          You suggested to me "readyRead" signal but now, I could not readyAll because, incomplated data is received

                          As already suggested: you need to accumulate incoming data in a buffer. readyRead() signal can be emited several times until you get everything.

                          "Do you mean say "finished" signal ?" - yes
                          https://doc.qt.io/qt-6/qnetworkreply.html#finished
                          It even explains: "In particular, if no calls to read() were made as a result of readyRead(), a call to readAll() will retrieve the full contents in a QByteArray."

                          https://forum.qt.io/topic/113070/qt-code-of-conduct

                          J 1 Reply Last reply
                          1
                          • jsulmJ jsulm

                            @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                            You suggested to me "readyRead" signal but now, I could not readyAll because, incomplated data is received

                            As already suggested: you need to accumulate incoming data in a buffer. readyRead() signal can be emited several times until you get everything.

                            "Do you mean say "finished" signal ?" - yes
                            https://doc.qt.io/qt-6/qnetworkreply.html#finished
                            It even explains: "In particular, if no calls to read() were made as a result of readyRead(), a call to readAll() will retrieve the full contents in a QByteArray."

                            J Offline
                            J Offline
                            Joe von Habsburg
                            wrote on last edited by Joe von Habsburg
                            #42

                            @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                            As already suggested: you need to accumulate incoming data in a buffer. readyRead() signal can be emited several times until you get everything.

                            Hmm now I should not assign reply->readAll(), I should append :). I will try it.

                            _sample.append(_replySample->readAll());
                            

                            @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                            "Do you mean say "finished" signal ?" - yes

                            I cannot use it because memory leak.

                            jsulmJ 1 Reply Last reply
                            0
                            • J Joe von Habsburg

                              @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                              What does this have to do with buffering incoming data?
                              To get a simpler solution follow @Christian-Ehrlicher suggestion.

                              I could not see requestFinished signal on documentation. Do you mean say "finished" signal ?

                              @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                              don't understand your point or question here?

                              My question is that. if I use "finished" signal memory leak.

                              @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                              _reply->readyRead()

                              You suggested to me "readyRead" signal but now, I could not readyAll because, incomplated data is received.

                              For example, data's size must be 350000, but i receive 348000 or less. As a result of for that I crashed.

                              @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                              QNetworkReply::downloadProgress()

                              I try check will have arrived data size use with "downloadProgress" signal and my QByteArray data size is equal ? but so many times thay are not.

                              How can I wait all data complate without use "finished" signal because memory leak?

                              @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                              As I wrote earlier, if you do not want to handle partial data as it arrives, and are using reply auto-delete so you cannot access it after it has finished, you can place a slot on QNetworkReply::finished and readAll() the data there in one go, before allowing the reply to be deleted.

                              I don't understand. Can you give me code example ?

                              JonBJ Offline
                              JonBJ Offline
                              JonB
                              wrote on last edited by kshegunov
                              #43

                              @Joe-von-Habsburg
                              As @jsulm has said. With QNetworkAccessManager::setAutoDeleteReplies(true) set you should be able to use either of the following approaches:

                              QByteArray _bytesRead;    // class member variable
                              
                              _bytesRead.clear();
                              connect(_reply, &QNetworkReply::finished, this, &Class::onFinished);
                              _reply = _manager.get(_request);
                              
                              void Class::onFinished()
                              {
                                  _bytesRead = _reply->readAll();    // read all bytes in one go at the end, just before `_reply` gets auto-deleted
                              }
                              

                              or

                              QByteArray _bytesRead;    // class member variable
                              
                              _bytesRead.clear();
                              connect(_reply, &QNetworkReply::readyRead, this, &Class::onReadyRead);
                              connect(_reply, &QNetworkReply::finished, this, &Class::onFinished);
                              _reply = _manager.get(_request);
                              
                              void Class::onReadyRead()
                              {
                                  _bytesRead += _reply->readAll();    // *append* this time's bytes read to buffer
                              }
                              
                              void Class::onFinished()
                              {
                                  // I think `_bytesRead` should contain all data by now, when reply has finished
                                  // If not call `_bytesRead += _reply->readAll();` or `onReadyRead()` one last time
                              }
                              

                              [Edit: Fixed code highlighting ~kshegunov]

                              J 1 Reply Last reply
                              2
                              • J Joe von Habsburg

                                @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                                As already suggested: you need to accumulate incoming data in a buffer. readyRead() signal can be emited several times until you get everything.

                                Hmm now I should not assign reply->readAll(), I should append :). I will try it.

                                _sample.append(_replySample->readAll());
                                

                                @jsulm said in Qt6 Windows slower than Qt6 Ubuntu:

                                "Do you mean say "finished" signal ?" - yes

                                I cannot use it because memory leak.

                                jsulmJ Offline
                                jsulmJ Offline
                                jsulm
                                Lifetime Qt Champion
                                wrote on last edited by
                                #44

                                @Joe-von-Habsburg said in Qt6 Windows slower than Qt6 Ubuntu:

                                cannot use it because memory leak.

                                There should not be memory leak unless your code is wrong.
                                Simply connect a slot to finished() signal and in that slot call readAll() and deleteLater() on the reply.

                                https://forum.qt.io/topic/113070/qt-code-of-conduct

                                1 Reply Last reply
                                2
                                • JonBJ JonB

                                  @Joe-von-Habsburg
                                  As @jsulm has said. With QNetworkAccessManager::setAutoDeleteReplies(true) set you should be able to use either of the following approaches:

                                  QByteArray _bytesRead;    // class member variable
                                  
                                  _bytesRead.clear();
                                  connect(_reply, &QNetworkReply::finished, this, &Class::onFinished);
                                  _reply = _manager.get(_request);
                                  
                                  void Class::onFinished()
                                  {
                                      _bytesRead = _reply->readAll();    // read all bytes in one go at the end, just before `_reply` gets auto-deleted
                                  }
                                  

                                  or

                                  QByteArray _bytesRead;    // class member variable
                                  
                                  _bytesRead.clear();
                                  connect(_reply, &QNetworkReply::readyRead, this, &Class::onReadyRead);
                                  connect(_reply, &QNetworkReply::finished, this, &Class::onFinished);
                                  _reply = _manager.get(_request);
                                  
                                  void Class::onReadyRead()
                                  {
                                      _bytesRead += _reply->readAll();    // *append* this time's bytes read to buffer
                                  }
                                  
                                  void Class::onFinished()
                                  {
                                      // I think `_bytesRead` should contain all data by now, when reply has finished
                                      // If not call `_bytesRead += _reply->readAll();` or `onReadyRead()` one last time
                                  }
                                  

                                  [Edit: Fixed code highlighting ~kshegunov]

                                  J Offline
                                  J Offline
                                  Joe von Habsburg
                                  wrote on last edited by
                                  #45

                                  @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                                  QByteArray _bytesRead; // class member variable

                                  _bytesRead.clear();
                                  connect(_reply, &QNetworkReply::readyRead, this, &Class::onReadyRead);
                                  connect(_reply, &QNetworkReply::finished, this, &Class::onFinished);
                                  _reply = _manager.get(_request);

                                  void Class::onReadyRead()
                                  {
                                  _bytesRead += _reply->readAll(); // append this time's bytes read to buffer
                                  }

                                  void Class::onFinished()
                                  {
                                  // I think _bytesRead should contain all data by now, when reply has finished
                                  // If not call _bytesRead += _reply->readAll(); or onReadyRead() one last time
                                  }

                                  its work !!! Thank you so much

                                  JonBJ 1 Reply Last reply
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                                  • J Joe von Habsburg has marked this topic as solved on
                                  • J Joe von Habsburg

                                    @JonB said in Qt6 Windows slower than Qt6 Ubuntu:

                                    QByteArray _bytesRead; // class member variable

                                    _bytesRead.clear();
                                    connect(_reply, &QNetworkReply::readyRead, this, &Class::onReadyRead);
                                    connect(_reply, &QNetworkReply::finished, this, &Class::onFinished);
                                    _reply = _manager.get(_request);

                                    void Class::onReadyRead()
                                    {
                                    _bytesRead += _reply->readAll(); // append this time's bytes read to buffer
                                    }

                                    void Class::onFinished()
                                    {
                                    // I think _bytesRead should contain all data by now, when reply has finished
                                    // If not call _bytesRead += _reply->readAll(); or onReadyRead() one last time
                                    }

                                    its work !!! Thank you so much

                                    JonBJ Offline
                                    JonBJ Offline
                                    JonB
                                    wrote on last edited by
                                    #46

                                    @Joe-von-Habsburg
                                    Do your timings/memory consumption with this asynchronous approach (i.e. no _loop.exec()) and not with that original while() loop. (If you want to run it more than once, after you get finished() on one start the next one there or on a QTimer::singleShot().) See whether you still get bad performance on one versus the other.

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                                    • JonBJ JonB

                                      @Joe-von-Habsburg
                                      Do your timings/memory consumption with this asynchronous approach (i.e. no _loop.exec()) and not with that original while() loop. (If you want to run it more than once, after you get finished() on one start the next one there or on a QTimer::singleShot().) See whether you still get bad performance on one versus the other.

                                      J Offline
                                      J Offline
                                      Joe von Habsburg
                                      wrote on last edited by
                                      #47

                                      @JonB

                                      Last edit my code :

                                      DataReceiver::DataReceiver(QObject *parent)
                                         : QObject{parent}
                                      {
                                         _manager.setAutoDeleteReplies(true);
                                      }
                                      void DataReceiver::start()
                                      {
                                         _connection++;
                                         if(_connection > 1)
                                             return;
                                      
                                         _takeData = true;
                                         run();
                                      }
                                      
                                      void DataReceiver::stop()
                                      {
                                         _takeData = false;
                                         _connection = 0;
                                         _data.clear();
                                      }
                                      
                                      
                                      void DataReceiver::getData()
                                      {
                                         _data.clear();
                                         QString url = QString("http://localhost:%1/sample").arg(_port);
                                         QUrl _apiUrl(url);
                                         QNetworkRequest _request(_apiUrl);
                                         _reply = _manager.get(_request);
                                         connect(_reply, &QNetworkReply::readyRead, this, &DataReceiver::onReadReady);
                                         connect(_reply, &QNetworkReply::finished, this, &DataReceiver::onFinished);
                                      }
                                      
                                      
                                      void DataReceiver::run()
                                      {
                                         if(!_takeData)
                                             return;
                                      
                                         getData();
                                      }
                                      
                                      void DataReceiver::onReadReady()
                                      {
                                         _data += _reply->readAll();
                                      }
                                      
                                      void DataReceiver::onFinished()
                                      {
                                         emit sendData(_data);
                                         run();
                                      }
                                      

                                      its working. time slow down from 65ms to 165ms but its working.

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