Version Upgrade from Qt 5.2.1 to Qt 5.5.1 caused heavy performance drop

[turtle]

Hello everyone,

this is a thread I never expected to open, but today I ran into a problem when updating my Qt-version.

I was happily using Qt 5.2.1 32 bit with MinGW 4.8 and QtCreator 3.0.1 (based on Qt 5.2.1 (MSVC 2010, 32 bit)). Then I needed the Websocket support that was only added in Qt 5.3. So why not download the newest version? So I installed Qt 5.5.1 32 bit with MinGW 4.9 and Qt Creator 3.5.1 (opensource) (based on Qt 5.5.1 (MSVC 2013, 32 bit)).

At first, I could not compile my application. Then I figured out it was due to a lib of myself that I was using that was created with Qt 5.2.1. So I compiled it with Qt 5.5.1, and then I could also compile my application. But what a change! The performance has hugely dropped! I have a lot of qDebug() in my code. With Qt 5.2.1 I could see if running very fast through the console. But now, a) the color of the text is pink (any reason why? i was not debugging...) and b) the qDebug() output now runs quite slowly through the console. And opening a complex widget (no code changes!) takes 15 seconds, with Qt 5.2.1 it opened instantly!

I can only think that a reason could be that the install path is not "optimal"?

Qt 5.2.1 is installed here:
C:/Qt/...
Qt 5.5.1 is installed here:
C:/Qt5.5.1/

My computer is runnning Windows 8 64 bit.

I tried to disable the qDebug() messages to see if there is the root cause, with

CONFIG(release,release|debug){
    DEFINES += QT_NO_DEBUG_OUTPUT
}

CONFIG(release,release|debug){
    DEFINES += QT_NO_DEBUG_OUTPUT
}

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But this did nothing at all (I mean: the qDebug()-messages did not disappear), even after cleaning and rebuilding everything.

Or can the problem be due to the QtCreator community edition?

[anda_skoa]

Or can the problem be due to the QtCreator community edition?

No, there is no difference in versions of the same version number.

You could try category based logging, so you can enable/disable categories on a case by case basis as needed.

Cheers,
_

[turtle]

I just installed Qt 5.3.2 and everything is working, the performance as well. There's something seriously wrong about the Qt 5.5.1 version...