Qt5's Linux Requirements Cause Problems

[JS987]

Qt 5 is using the raster engine, so no GUI operation is actually hardware accelerated (that model of accelerating "lines" and "triangles" on 2D GUIs has been outdated for years now on most modern operating systems.) So using XCB is fine.

Qt 4 is 6.5 times slower with raster engine than with native engine on Intel G33 graphics card

qtperf4 -graphicssystem native
QLineEdit - 0.022 s
QComboBox - 0.19 s
QComboBoxEntry - 0.183 s
QSpinBox - 0.015 s
QProgressBar - 0.021 s
QPushButton - 0.016 s
QCheckbox - 0.007 s
QRadioButton - 0.019 s
QTextEdit add text - 0.057 s
QTextEdit scroll - 0.048 s
QPainter lines - 12.95 s
QPainter circles - 13.1 s
QPainter text - 1.356 s
QPainter pixmap - 0.088 s
Total: 28.072001 s

qtperf4 -graphicssystem raster
QLineEdit - 0.043 s
QComboBox - 0.336 s
QComboBoxEntry - 0.327 s
QSpinBox - 0.024 s
QProgressBar - 0.04 s
QPushButton - 0.017 s
QCheckbox - 0.014 s
QRadioButton - 0.035 s
QTextEdit add text - 0.175 s
QTextEdit scroll - 0.148 s
QPainter lines - 86.218 s
QPainter circles - 86.222 s
QPainter text - 8.689 s
QPainter pixmap - 0.867 s
Total: 183.154999 s

[abrahm]

Intel Mesa developers have stated that GLX is "pretty much" deprecated and you should be using EGL anyway. See http://www.phoronix.com/scan.php?pag...tem&px=MTE3MTI.

[jrdls]

Somebody made a post saying that using XCB means you are relying on Mono... that is a completely factually wrong statement and I'm a little confused as to how anyone could even come up with something that weird.

A little more seriously, could the original writer of the rant look into using EGL instead of GLX? Apparently GLX is quickly on its way to deprecation anyway, so EGL could be the right way to go. I'm not sure what sort of functionality he needs, but I hope that the XCB bindings (or another API interface) would give it to him. If he is just writing a window manager then I'm not sure why he needs low-level access to the guts of OpenGL anyway...

Completely agree. MESA developers discourage the use of GLX. EGL is usable and is a Khronos standard. And since Qt is all about portability, his code should run on more platforms, EGL being platform agnostic.

[DanL]

Michael, there are 2 vulgar words in this article. Please don't publish such rants.

Coarse language is a fact of life. If it really bothers you, turn on a parental filter. Personally, I can't stand advertising, so I block that.

[bwat47]

Qt 4 is 6.5 times slower with raster engine than with native engine on Intel G33 graphics card

qtperf4 -graphicssystem native
QLineEdit - 0.022 s
QComboBox - 0.19 s
QComboBoxEntry - 0.183 s
QSpinBox - 0.015 s
QProgressBar - 0.021 s
QPushButton - 0.016 s
QCheckbox - 0.007 s
QRadioButton - 0.019 s
QTextEdit add text - 0.057 s
QTextEdit scroll - 0.048 s
QPainter lines - 12.95 s
QPainter circles - 13.1 s
QPainter text - 1.356 s
QPainter pixmap - 0.088 s
Total: 28.072001 s

qtperf4 -graphicssystem raster
QLineEdit - 0.043 s
QComboBox - 0.336 s
QComboBoxEntry - 0.327 s
QSpinBox - 0.024 s
QProgressBar - 0.04 s
QPushButton - 0.017 s
QCheckbox - 0.014 s
QRadioButton - 0.035 s
QTextEdit add text - 0.175 s
QTextEdit scroll - 0.148 s
QPainter lines - 86.218 s
QPainter circles - 86.222 s
QPainter text - 8.689 s
QPainter pixmap - 0.867 s
Total: 183.154999 s

Are you using sna?

[JS987]

Are you using sna?

Yes with Intel driver 2.20.7 and Xserver 1.12.4

[beevvy]

Yes with Intel driver 2.20.7 and Xserver 1.12.4

FWIW, in my case the difference is even bigger, in favor of native, too. Mobile Intel Sandybridge, SNA. But this is slightly off-topic

[bwat47]

Yes with Intel driver 2.20.7 and Xserver 1.12.4

Here's the results on my machine (intel ironlake with sna, xorg 1.12.4, kernel 3.5, kde 4.9.1)

raster: http://i.imgur.com/Cmlv1.png
native: http://i.imgur.com/wXEiZ.png

Definitely not as big of a difference on my machine, but native does seem slightly faster here too.

[curaga]

Completely agree. MESA developers discourage the use of GLX. EGL is usable and is a Khronos standard. And since Qt is all about portability, his code should run on more platforms, EGL being platform agnostic.

EGL hardly has an installed base right now. Maybe in five years you can rely only on it.

By my count, EGL is available on mobiles, mesa git, recent blobs. Not on much of the linux systems, nor Windows or Macs. (not 100% sure on the EGL situation on Macs)

[cb88]

Of course crass language is a part of life.. its the part that causes me to cease caring about reading Phoenix articles which are often incorrect but at least retained some semblance of professionalism.