[Interest] Rotating objects in QML are killing performance

[Sean Harmer]

On Monday 15 April 2013 12:08:34 Michael Andersen wrote:
> On 15 April 2013 11:56, Rutledge Shawn <Shawn.Rutledge at digia.com> wrote:
> > On 12 Apr 2013, at 11:47 PM, Michael Andersen wrote:
> > > I found the root of the problem: there is something fishy with Nvidia's
> > 
> > sync to vblank implementation. If Vsync is turned off, everything works
> > ok,
> > if it is turned on then all hell breaks loose. I just downloaded and
> > installed their latest drivers (310.44) and the problem still exists
> > there.
> > 
> > > So, sorry for the noise, it seems Nvidia is to blame. Unfortunately
> > 
> > Vsync was on to fix a different Nvidia bug, so now I have to choose the
> > lesser of the two :/ I am reminded of Linus's outburst at Nvidia last
> > year.. feeling pretty annoyed right now.
> > 
> > I was having good luck with nouveau for a while, but some recent versions
> > started crashing the whole system (quite hard, I couldn't even ssh in and
> > tell it to reboot) so I went back to using proprietary drivers for a
> > while.
> 
> I have also had problems with nouveau, but I never have time to file bug
> reports so I can't complain.
> 
> > At the moment I can run multiple copies of glxgears, get 60 FPS and
> > without much CPU usage.  I have version 313.26.
> 
> For my card, my version (310.44) is the latest that the nvidia site offers
> me (and is newer than all the versions in the Ubuntu repository), what card
> do you have and did you opt for beta drivers or something similar? With
> sync to VBlank, I get 60FPS with almost no CPU usage until I attempt to
> drag windows, then all hell breaks loose. I'll see if I can find a newer
> driver and retest.

I get no problems whilst dragging windows here with the 310.x or 313.x series 
drivers and a GeForce 570 GPU. However, this is on kwin rather than unity. 
Have you tried other compositing window managers? It could well be something 
in that layer not interacting nicely.

Sean

--
Dr Sean Harmer | sean.harmer at kdab.com | Senior Software Engineer
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