[winswitch] xpra: high %cpu when start a background application

Antoine Martin antoine at nagafix.co.uk
Sat Sep 6 05:40:26 BST 2014

On 06/09/14 10:07, Long Nguyen Thanh wrote:
> Hi all,
> (sorry if my English is not good)
> I'm using server Ubuntu 12.04 with xpra 0.14-1, client Windows 7 Pro with
> xpra 0.14
(those version numbers are incomplete, and if you really are using
0.14.0 then you should upgrade it)
> Reproduce:
> A.
> 1.At server: xpra start :100 --start-child=myapp --bind-tcp=
> myapp is an application without GUI.
> 2. At client : xpra attach tcp:IP:20000
> 3. At server : top -> %CPU xpra ~ 10%
Does removing your app make any difference? (just connecting xpra)
My guess is that sound forwarding is using your CPU for compression (mp3
or other).
Yes, even when no sound is being played:
> B.
> 1.At server: xpra start :100 --start-child=firefox--bind-tcp=
> 2. At client : xpra attach tcp:IP:2000
> 3. At firefox windows: Open some website ( youtube,...) and check :
> %CPU ~ 25% - *75%*
Firefox will repaint the screen regularly, so yes, a high CPU usage with
such an application is to be expected.
(animated gifs, flash adverts, widgets, etc)
> So is it normal with those %CPU when use xpra?
As per above, turn off sound if you don't use it.
Any screen updates will also consume bandwidth and CPU, minimizing the
application when you're not using it will prevent that.
I have added those questions to the FAQ:


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