A Lighter, Faster (?) Plasma

[Rog131]

The Qt (Qt 4.5 or later) has an option to use different graphics system to draw the desktop objects > QApplication Class Reference

...
All Qt programs automatically support the following command line options:-graphicssystem, sets the backend to be used for on-screen widgets and QPixmaps. Available options are raster and opengl.
...
...which will be used for on-screen widgets and QPixmaps. The available systems are "native", "raster" and "opengl".

True Believers & Heathens a.k.a should we or shouldn't we > Qt 4.5 RC1 packages for Intrepid, built with -graphicssystem raster


The > kubuntu-devel -- Kubuntu Developer Discussion >> graphicssystem raster

Scott Kitterman
Sat Jul 11

At UDS we had some discussion about switching to raster would make Kubuntu a
lot faster.

Did anyone do anything on this? Faster is important ....

Scott K

Here with the Ati/opensource the raster option seems to be a bit lighter for the CPU. Tested with the > Star Field Plasma Wallpaper. /1/

Description:
This plasma wallpaper draws an animated starfield in the background of your

CPU USAGE
---------
This wallpaper can be quite CPU intensive. To reduce the CPU usage you may try
...
- Use plasma in raster mode. To do this first quit plasma then restart it with
-graphicssystem raster argument:
For KDE 4.2:
kquitapp plasma
plasma -graphicssystem raster

For KDE 4.3:
kquitapp plasma-desktop
plasma-desktop -graphicssystem raster

However be wary that this method has not been thoroughly tested.

Here, with the default plasma settings the CPU load is 100% and with the "raster" it is
about 80 %.

The startfield settings are:
Number of stars: 100
Star Speed is low
No background


Here everything seems to work fine, "desktop effects" are working , no artifacts on the screen. Note, though that i have been using the raster setting only two days...


/1/ Packages could be found from the > PPA repositories (> FAQ: Repositories) >> Show PPAs matching: starfield

[Fintan]

Re: A Lighter, Faster (?) Plasma

Thank you rog.

How do I get back to the "normal" mode if raster borks something?

[Rog131]

Re: A Lighter, Faster (?) Plasma

With the:

kquitapp plasma
plasma

or log out log in.


The "opengl" option seems to be under work (?). It is not usable at here - the desktop start to blink, windows are showing and disappearing...

The "opengl" is not the same as the System Settings > Desktop > Desktop Effects > Compositing type: OpenGL.


OpenGL here:

glxinfo |grep "OpenGL"

OpenGL vendor string: DRI R300 Project
OpenGL renderer string: Mesa DRI R300 20060815 AGP 8x x86/MMX+/3DNow!+/SSE TCL
OpenGL version string: 1.3 Mesa 7.4

[Fintan]

Re: A Lighter, Faster (?) Plasma

Okay
I should have guessed that.

I tried it on the lappy I am testing: hp pavilion ze4931ea and it gives me this:

ubuntu@ubuntu-laptop:~$ plasma -graphicssystem raster
<unknown program name>(13755)/ checkComposite: Plasma has an argb visual 0x94e2848 29360129
<unknown program name>(13755)/ checkComposite: Plasma is COMPOSITE-less on 0x94e2118
QLayout: Attempting to add QLayout "" to QWidget "", which already has a layout
Object::connect: Attempt to bind non-signal TaskManager::TaskGroup::editRequest()
QCoreApplication:ostEvent: Unexpected null receiver
QGraphicsGridLayout::itemAt: invalid index 0
QGraphicsGridLayout::itemAt: invalid index 2
QGraphicsGridLayout::itemAt: invalid index 7
QPainter::begin: Paint device returned engine == 0, type: 2
QCoreApplication:ostEvent: Unexpected null receiver
QCoreApplication:ostEvent: Unexpected null receiver
ubuntu@ubuntu-laptop:~$

but it seems to be working alright. I'll test for a while here.

[Rog131]

Re: A Lighter, Faster (?) Plasma

There's no such thing as a free meal > graphicssystem raster

Jonathan Thomas
Tue Jul 14 03:26:19 BST 2009
...
Yes, it would make things faster, however it also greatly increases RAM
consumption since everything is being rendered in software.
Here's the result of a quick benchmark on my part:...

[KeithZG]

Re: A Lighter, Faster (?) Plasma

There's no such thing as a free meal > graphicssystem raster

Jonathan Thomas
Tue Jul 14 03:26:19 BST 2009
...
Yes, it would make things faster, however it also greatly increases RAM
consumption since everything is being rendered in software.
Here's the result of a quick benchmark on my part:...

I'd just settle for a meal that doesn't manage to somehow use up 75% CPU on a 2.4GHz processor

[Rog131]

Re: A Lighter, Faster (?) Plasma

I'd just settle for a meal that doesn't manage to somehow use up 75% CPU on a 2.4GHz processor

What kind of system do you have ? KDE 4.2/4.3, CPU/GPU (Intel/AMD/NVidia/...), Drivers (Open/Propietary)... ?

I have seen that there are problems > Topic: Kubuntu is super slow, Topic: Xrender or openGL for performance help, ...


Here the KDE 4.2 (Jaunty) is usable. The KDE 4.3 (Karmic) is having small lag. Both have CPU load about 8-10 % (when idle).

CPU AMD Athlon (Barton) XP 2500+ (1.83 GHz)
GPU AMD (ATI) Radeon 9600 XT, OpenSource drivers.


Promises (Would you buy a used car...)

> tokamak 3 on the home stretch

We've talked about future features and existing flaws in Qt with Qt developers. We've merged three different GSoC branches: remote widgets, widget explorer and KAuth. We've done profiling of Plasma and increased the speed of various things, sometimes radically: job tracking for file downloads will take virtually no CPU in 4.4 and very little (though a bit more) in 4.3.2. We've worked on context and integration with Nepomuk; better activity management and integration with KWin. New work on WebKit based technologies in KDE 4 has made leaps during our time here. We've put KDE 4 on a small ARM based device and, with Qt 4.6, Plasma runs really smoothly;..

> Third Plasma Summit Lifts KDE Desktop To Higher Grounds

...Using Qt 4.6 on the device gave another boost in speed.
...
Menard also talked about vast performance improvements in QGraphicsView and how these were achieved. For selected use-cases, the performance in handling items on the GraphicsView canvas has been improved by orders of magnitude. Those changes will automatically become available to KDE by using Qt 4.6.

There will always be tomorrow...

[KeithZG]

Re: A Lighter, Faster (?) Plasma

There will always be tomorrow...

Indeed! Actually. the earlier builds of KDE 4 (4.0, 4.1 and even 4.2) were hellishly slow on this primary PC of mine, 4.3 is the first one that's been usable at all on my main computer.

What kind of system do you have ? KDE 4.2/4.3, CPU/GPU (Intel/AMD/NVidia/...), Drivers (Open/Propietary)... ?

It's an AMD Athlon 64 X2 4400+ (so, 2.2 GHz), with a GeForce 7800 GTX running the blob drivers (version: 180.44).x And, as aforementioned, KDE 4.3 (on top of 9.04, since this is in theory my stable machine).

Worth mentioning is that I'm running a TwinView setup, with one 4:3 monitor and one 16:9 monitor; that seems to be one of the things that Plasma/KDE4 still can't handle as well in most respects as 3.5 can (and Buddha help me if I want to move the panel between screens!).

[Rog131]

Re: A Lighter, Faster (?) Plasma

> KCM Qt Graphics System:

Description:
This KCM allows you to easily configure the standard Qt graphics system.

[img width=400 height=224]http://kde-apps.org/CONTENT/content-pre1/129817-1.jpeg[/img]

[kubicle]

Re: A Lighter, Faster (?) Plasma

> KCM Qt Graphics System:

Description:
This KCM allows you to easily configure the standard Qt graphics system.

This config module is now available in the maverick repos, package "kde-config-qt-graphicssystem"

Tip: if fiddling with the backend renders your desktop unusable (at least the opengl backend can do that) you can fall back on the default backend by removing ~/.kde/env/qt-graphicssystem.sh

[MoonRise]

Re: A Lighter, Faster (?) Plasma

Can any of that be tested on 10.04? It seems to be for 10.10.

[claydoh]

Re: A Lighter, Faster (?) Plasma

you can build it in 10.04, but you need Qt 4.7 - which means you need KDE4.5 in lucid

[kubicle]

Re: A Lighter, Faster (?) Plasma

And you don't really need the config module to test different graphics backend (provided you have qt 4.7, that supports setting the graphicssystem via environment variable).

For example, to test the raster backend, just create a file ~/.kde/env/qt-graphicssystem.sh (although the name shouldn't really matter) with the contents:
export QT_GRAPHICSSYSTEM=raster
and relog into kde.

[GreyGeek]

Re: A Lighter, Faster (?) Plasma

My plasma-desktop CPU usage oscillates between 1 and 5%.

What causes it to consume 100% of the CPU?

[sithlord48]

Re: A Lighter, Faster (?) Plasma

i haven't seen plasma eat all my cpu .... either way i've switched to raster graphics, (kubicle's method) and i see plasm-desktop now uses no more then 1% on this machine,

AMD, athlon phenom II 940BE @3.0ghz (quad core)
4gb RAM ddr2 @1066mhz (yes i have the older 940 BE...)
ati Radeion 4830HD, ati driver v.10.8 dual head (one 16:10 one 4:3 screen)

the real test will be to see how it does on my netbook. its a bit lighter on the internal resorces. oh that and less cpu time = more time for juk to play me music while i drive around @ work :P , i will attempt to get it after i look at plasma-desktop's usage on the machine for a while so i have an idea of how much (if any) cpu time is saved..

i think that anything that can be done to give kde a speed boost is a good idea.