Qt apps >= 5.4.0 (and qtcreator built against that) slow over ssh X
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Ever since the version of qt creator that used qt 5.4.0, and apps built against that, it's a horrible experience to use over ssh -X. Looking around, I see stuff with opengl was changed. I understand that there are a few modes of operation of opengl and qt chooses automatically. However, I'd like to manually chose each mode and see if the performance gets better. I think qt4 had --graphicssystem, but is there a qt 5 equivalent?
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Hi and welcome to devnet,
Just to be sure I understand you correctly: are you comparing Qt 4 and Qt >= 5.4 ? Or do you mean that there's been a performance drop from 5.3 to 5.4 ?
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Hi and welcome to devnet,
Just to be sure I understand you correctly: are you comparing Qt 4 and Qt >= 5.4 ? Or do you mean that there's been a performance drop from 5.3 to 5.4 ?
@SGaist I am comparing different versions of Qt 5. It was qtcreator 3.4.2 that had the slowdown compared to 3.4.1 (looking at the changelog, it looked like it was actually moved to Qt 5.5). I guess I'm comparing Qt >=5.5 to Qt <5.5. Is there a way though to chose what opengl system it will use?
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What do you mean by "choosing an OpenGL system" ?
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@SGaist It looks like there are 3 different "implementations" (or whatever they should be called): http://doc.qt.io/qt-5/windows-requirements.html
desktop
angle
softwareThat environment variable seems to have no effect in Linux. The page looks windows specific. Do I have the same choices in Linux? I'd like to choose what rasterizer it uses.
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They won't indeed. Windows is a bit of a special case here. ANGLE is used for system that don't have a "real OpenGL" driver available.
On Linux you have the xcb backend unless you go Xless.
You should check the bug report system to see if there was something reported there
