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  1. Qt
  2. QTBUG-89867

The efficiency of QList append method in QT6 is much lower than that in QT5

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    Details

    • Type: Suggestion
    • Status: Closed
    • Priority: Not Evaluated
    • Resolution: Out of scope
    • Affects Version/s: 6.0.0
    • Fix Version/s: None
    • Labels:
      None
    • Platform/s:
      Windows

      Description

      Why is the efficiency of QList append method  in QT6  much lower than that in QT5?

      The average time of appending 1000000 data(ms)

        qt5.13.1 qt6.0.0
      debug 350 1300
      release 75 130
      #include <QCoreApplication>
      #include "QList"
      
      struct TradeData{
       QDateTime beginDate;
       QString exchangeID;
       double beginPrice=0;
       double endPrice=0;
       int num=0; 
      };
      
      int main(int argc, char *argv[])
      {
       QCoreApplication a(argc, argv); 
       qint64 start=QDateTime::currentMSecsSinceEpoch();
       TradeData td;
       td.begindate=QDateTime::currentDateTime();
       QList<TradeData>temp;
       for(int i=0;i<1000000;++i){
       temp.push_back(td);
       }
       qint64 interval=QDateTime::currentMSecsSinceEpoch()-start;
       std::cout<<"time:"<<interval<<std::endl;
      
      return a.exec();
      }
      

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            Assignee:
            thiago Thiago Macieira
            Reporter:
            marsman Jiayu g
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              Updated:
              Resolved:

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