{July 5, 2007}   kwin composite

so a few days ago, I decided I wanted to enable those shiny kwin_composite features that I’ve seen so many youtube videos of. I was up pretty late figuring it out.

first, make showed me this:
— The following list of OPTIONAL packages were located on your system. —
— You will have all the following features available from this software. —
+ Compositing support

…regardless of whether libxcomposite-dev was actually installed.

then, when I actually started x, I wanted to get at the kwin debug info, so I do kwin –replace and get this:
kwin: Compositing was not available at compile time

so do I have composite, or don’t I?

eventually I went digging in the source, and found that while cmake only checks for xrender and xcomposite, the actual composite.cpp first checks for xcomposite and xdamage. naturally I don’t have this xdamage thing installed.

installed that, recompiled, and everything was all wonderfully pretty! :)
maybe this would’ve been solved with a svn up, since my sources are a few weeks old, but I originally though it would be too slow to download and rebuild kdelibs, kdepimlibs, etc.

unfortunately composite was unusably slow, though. I’ve got intel graphics and haven’t really looked into whatever acceleration options there might be… I’m not really sure where to start, actually. anyone got any tips for making composite stuff go at a normal speed? I know my comp should be capable of it – it may not be a very powerful machine, but I can at least play neverball.

oh, and wendy: your blog won’t let me comment. blogger doesn’t seem to accept my google account, and you don’t have anonymous comments on. I wanted to say that the konqui intro idea sounds hard to do without ending up like clippy, but konquigotchi sounds like a good game idea :)

As far as sorting out compositing performance is concerned, this generally works for compiz/beryl:

-Look for extensions that change the output of windows a lot (bluring is the prime suspect here, but some animations are also guilty). These use shaders and thus require programmable graphics hardware (generally GeForce 4 up on NVidia). Actually only one intel chipset has this feature (called Hardware T&L, or Transform and Lighting), the 3000X (note the X). Not many laptops have this, even though it’s lickly to become more common (needed for Vista Aero apparently).

-Memory, you’re average graphics card comes with 256MB of Ram (shared for most laptop intels). For games, this is still plenty, but for applications, where the entire graphics output has to be stored inside this 256MB, it can become tight very quickly (especially when fragmentation kicks in). Try lowering your resolution. Also, try to have as few as possible (full screen) windows open on the same side of the cube (his also applies if you only see a small part of the window). Breaking through the 256MB barrier isn’t fatle, but performance will suffer a lot.

-CPU. Yes I know, this should be GPU stuff. But we’re talking about intel chips here (if you’ve got a

Sorry, subbited by mistake,

As I was writing, if you’ve got a 3000X you can ignore this, but the other intel chipsets can make a serious dent in your CPU when runing a compisit manager. Dual core is preferred in this case.

Anyhow, HTH


Chani says:

I don’t think this is a matter of disabling features or reducing resolution. the entire system slows to a crawl from the very beginning, before any windows are even opened. anything that requires composite stuff takes at least 5-10 seconds. even typing in konsole felt laggy.

oh, and when I log out, X hangs in a way that I have to hibernate my laptop to regain control of the system. no keyboard shortcut will either kill it or get me to another vt until after I come back from hibernation.

Lubos Lunak says:

If you’re interested in helping with getting it working with your card, it might be better to try to do so on the mailing list rather than in your blog. None of the people working on KWin have Intel gfx card.

Woei says:

Well, using an i855GM card, using compositing in 24bpp is indeed unusably slow. However, lowing the color depth to 16bpp makes it somewhat usable again (aside from scrolling, which still remains laggy like in Mac OS X).

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