XRUNS - Compositor - Mysterious Things

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lilith
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XRUNS - Compositor - Mysterious Things

Post by lilith »

Edit: Problem seems to be RENOISE related. With Reaper I don't observe it! Maybe someone can try to reproduce?

Hi,

I fear I need some help again. I'm using the debian stock kernel (4.9.0-8-amd64) at the moment and today I found a really strange issue:

When I disable the compositing in XFCE or don't use Compton (using both at the same time is not possible) as the compositor I very quickly get xruns and the DSP load is driving roller coaster. When I enable Compton or the XFCE own compositor everything goes back to normal. Strange thing is that I never stumbled upon that issue. Also I would think that using a compositor will make xruns more likely in any case, but actually this is not what I observe.

It also happens with kernel 4.9.0-7-amd64.

I made a little video:
While it's playing with Compton until ~ 0:30 the Renoise DSP load is ~16%.
Then after killing compton it's increasing to 25% and running the xrun counter script give the first xruns at ~64% or lower....

At 1:55 I started compton again and DSP load goes down again. When starting the xrun counter script I get the first xrun at > 90% (not shown).

https://vimeo.com/322604219

with the RT kernel I don't see any DSP load difference between Compton running or not, but when running the xrun script I get much earlier xruns when compton is not running. Also the xorg process is reaching >80% CPU when compton is not running.
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Re: XRUNS - Compositor - Mysterious Things

Post by merlyn »

I found that disabling compositing helped when I used AV Linux with an Nvidia graphics card. I'm fairly sure that that was an Nvidia issue, and not anything directly related to compositing itself.

Conceptually you would think compositing could actually help by taking some graphics load off the CPU.

I'm curious why you've gone to a stock kernel, rather than RT.
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Re: XRUNS - Compositor - Mysterious Things

Post by lilith »

merlyn wrote:I found that disabling compositing helped when I used AV Linux with an Nvidia graphics card. I'm fairly sure that that was an Nvidia issue, and not anything directly related to compositing itself.

Conceptually you would think compositing could actually help by taking some graphics load off the CPU.

I'm curious why you've gone to a stock kernel, rather than RT.
I assume that the RT is responsible for some freezes I observed in the last months. That's why i'm using the stock kernel. Concerning xruns I don't see any big difference.
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Re: XRUNS - Compositor - Mysterious Things

Post by lilith »

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Re: XRUNS - Compositor - Mysterious Things

Post by lilith »

That 's very strange and might only be solved by asking @#dri-devel and #gfx-intel.
If anyone is using Debian Stable with XFCE it would be interesting if it can be reproduced.
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Re: XRUNS - Compositor - Mysterious Things

Post by Detente »

Thanks, Lilith, for this info.
I am also curious about the cause/effects.

I tend to stay away from NVIDIA and HDMI at all times, yet I hadn't thought of disabling the compositor.
All I know is that on my own varieties of Linux implementations, the XFCE/window/desktop settings of compositor on or off didn't seem to make much difference to my audio work, so I stopped worrying about it. However, other sites mentioned that using Compiz or other fancy desktop 3D or animated interfaces could be bad for pro digital audio use.

I'll check back later to see what you find out.
I like to stay up to date on how to be "Linuxually Musical" :lol: :mrgreen:
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Re: XRUNS - Compositor - Mysterious Things

Post by lilith »

Funny thing is that there's no problem when using Awesome as the window manager.AFAIK Awesome doesn't use any compositing by default.

On wiki there is written that it is the first wm using XCB. Could this be the difference?
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