What should I do if my code get bad performance in newer Qt5 version?

[Mr Pang]

Hi,
I am developing a program recently. At the beginning, I choose Qt5.9.3 and the performance is satisfactory. But after upgrading Qt to newer version(had tried 5.9.4 5.9.5 5.9.7 5.10.0 5.11.0 5.12.0), the performance is more and more worse. I use perf to check out what happened, the result shows that below function is my bottleneck：

void MainWindow::updateModel(int row, Session *s, bool append)
{
    int i=0;   
    if(append){
        ue_list_model->setItem(row, i++, new QStandardItem(stat[s->getStat()]));
        ue_list_model->setItem(row, i++, new QStandardItem(s->getImsi().getImsiString()));
        ue_list_model->setItem(row, i++, new QStandardItem(s->getApn().getApn()));
        ue_list_model->setItem(row, i++, new QStandardItem(s->getRFTeidC().getFTeid()));
        QStandardItem *item = new QStandardItem(s->getDefaultBearer()->getRFTeidU().getFTeid());
        item->setToolTip(s->getRTeidUList());
        ue_list_model->setItem(row, i++, item);
        ue_list_model->setItem(row, i++, new QStandardItem(s->getLFTeidC().getFTeid()));
        item = new QStandardItem(s->getDefaultBearer()->getLFTeidU().getFTeid());
        item->setToolTip(s->getLTeidUList());
        ue_list_model->setItem(row, i++, item);
        ue_list_model->setItem(row, i++, new QStandardItem(s->getPaa().getPaa()));
        ue_list_model->setItem(row, i++, new QStandardItem(s->getRatType().getRatType()));
        ue_list_model->setItem(row, i++, new QStandardItem(s->getBearersEbi()));
        model_map[s] = ue_list_model->item(row);
        ue_list_model->item(row)->setData(QVariant::fromValue(s));
        for(int j=0;j<i;j++){
            ue_list_model->item(row, j)->setFlags(Qt::ItemIsSelectable|Qt::ItemIsEnabled|Qt::ItemNeverHasChildren);
        }
    }else{
        ue_list_model->item(row, i++)->setText(stat[s->getStat()]);
        ue_list_model->item(row, i++)->setText(s->getImsi().getImsiString());
        ue_list_model->item(row, i++)->setText(s->getApn().getApn());
        ue_list_model->item(row, i++)->setText(s->getRFTeidC().getFTeid());
        ue_list_model->item(row, i)->setText(s->getDefaultBearer()->getRFTeidU().getFTeid());
        ue_list_model->item(row, i++)->setToolTip(s->getRTeidUList());
        ue_list_model->item(row, i++)->setText(s->getLFTeidC().getFTeid());
        ue_list_model->item(row, i)->setText(s->getDefaultBearer()->getLFTeidU().getFTeid());
        ue_list_model->item(row, i++)->setToolTip(s->getLTeidUList());
        ue_list_model->item(row, i++)->setText(s->getPaa().getPaa());
        ue_list_model->item(row, i++)->setText(s->getRatType().getRatType());
        ue_list_model->item(row, i++)->setText(s->getBearersEbi());
    }
}

This function behaves good with Qt5.9.3 since I can not feel any delay. But with new version and same code, I can feel the delay of UI updating obviously. Should I treat this as a bug?

[SGaist]

Hi,

Performance regression are usually treated as bugs.

One thing you can to is check the release logs to see if anything related to that has changed between 5.9.3 and 5.9.4.