Stuttering on Linux with displays on.

[crs]

Hi,

I am still struggling with flying this bird smoothly. Stuttering I experience is pretty bad and does not allow me to enjoy this plane at all.

Here is previous post of mine which unfortunately did not get too much attention as 1.0 forum has been closed.

http://forums.x-pilot.com/index.php?topic=2345.msg22486#msg22486

Cameron, should I be able to fly her with on problems taking in consideration my spec (see below)? Lot's of people reports having no problems or whatsoever even with dual core CPU.

I would like to know whether it is down to my software or hardware.

Kind regards,

Kamil

[Japo32]

when you are flying or even on ground try to show the LEGs page in the FMS the less possible. Also the Holding page. Those pages are making great stutterings in low computers. But if you don't show them all will be fine.

[crs]

Hi Javier,

I have tried to swap FMC pages around. Regardless to which page is being shown I experience huge amount of stuttering. As soon as I switch Battery on (and then APU/GPU) stuttering starts. I do not experience it until having displays on.

Kind regards,

Kamil

[philipp]

Hi Kamil,

I'm unsure what the best advise for you is. I can only say I'm running Linux on a much weaker system, a notebook with Dualcore+hyperthreading (not a "real" quadcore) with a slow 256MB mobile NVidia graphics card and I don't experience any stuttering. Of course, performance in terms of FPS on my desktop computer is better, but on the notebook I have no noticeable stutters, only some minor ones when I display the LEGS page.

I'm using both OpenSuse 11.3 and Ubuntu 10.10 for testing, both manually equipped with the latest 270 nvidia drivers, (not beta, just latest stable manually installed with specific compiled kernel module) and results are actually better than when using windows on the same machine.

So my advise is:

-Look for background processes stealing CPU time. Google Chrome tends to suck up some load when running with a few tabs in the background for me.

-Do you already have a kernel with the so-called "wonder patch" to the scheduler?

-Try the latest nvidia drivers (not via distro-update, directly via nvidia-website)

Philipp

[MdMax]

Hi all !

Kamil, what's your window manager ? There's a nice Phoronix test on how Unity, Compiz, GNOME Shell & KWin affect OpenGL performance:

http://www.phoronix.com/scan.php?page=article&item=linux_desktop_managers1&num=1

:'( They didn't test X-Plane, nor X-Plane with the CRJ OpenGL displays, but maybe your system could give you a better experience with a very fast and light window manager.

http://en.wikipedia.org/wiki/Comparison_of_X_window_managers

You can also try to set the "display performance" to low in the FMC (MCDU MENU), but I'm not sure about the effect of this option.

Happy flying !

[crs]

Hi Philipp and MdMax,

This is exactly what I thought - my setup should be more than fine to run it. I am having pretty high FPS (jumping from 20s to 50s) and stuttering is present regardless to graphic settings in sim.

Something must be really wrong. Maybe I have a bottle neck somewhere else? HDD, MB?

I always turn off Chrome as it together with XPlane eats all memory and system gets pretty unresponsive. There is no heavy background tasks at all. All four cores are bored to death before I start XPlane.

I am using fluxbox - very minimalistic, so I wouldn't blame DM/WM. In regards to compiz&friends - I do not even have Compositing enabled in xorg (perhaps that is a cause? ).

Philipp, do you mean Big Kernel Lock? I am now using 2.6.39 with patch set provided by gentoo devs (gentoo-sources) but as far as I know it was completely removed in this release anyway (mainstream).

May I ask whether you are using 32 or 64 bits builds?

Philipp, is there any other piece of information that I could provide you with which would give you EUREKA-I-know-what-is-wrong-with-kamils-setup moment?

Kind regards,

Kamil

[MdMax]

:-\ Did you check the temperatures in your system with lm_sensors ?   I increased the fan speed of my big copper Zalman cooler since I fly with the CRJ.

Do you have dust in your computer case ?

How do you install your Nvidia driver ? Are you using the setup file from Nvidia.com ?

[crs]

Hi MdMax,

Yes, I may do have some dust but shouldn't be anything major.

In terms of temperatures:

CPU ~ 70°C

GPU ~ 60°C

MB ~ 50°C

and raising just by few degrees with CRJ (machine has been used for hours).

I do install nvidia drivers using gentoo's package manager.

Kind regards,

Kamil