[winswitch] [XPRA] server-side performance with many users

[Antoine Martin]

On 07/01/2020 12:08, Patrick Fleckenstein via shifter-users wrote:
> Hi,
> 
> I'm running XPRA on Ubuntu headless server. 100GB RAM, 16CPUs, 10Gb network interface.
> If connecting with a small amount of remote machines performance is great.
> 
> But in my environment nearly 200 users have to log in at the same time with their own account.
> Therefor I created a script checking on local startup if a xpra process is running for this user.
> If not it starts.
> 
> If many users are connected (~90+) performance gets worse with linux load at 200+.
90 is a quite a lot for just 16CPUs.

> Is there a performance hack for such a setup or a best practise?
Here are some ideas:
1) turn off any option you don't need, ie: in particular turn off audio 
if you don't need it and don't bother starting pulseaudio at all
2) sacrifice some bandwidth for CPU usage by increasing the default 
value for "min-speed" (assuming that you have bandwidth to spare)
3) sacrifice some quality: reduce "min-quality"
4) use picture encodings that are light on CPU usage: rgb+lz4 or jpeg on 
low quality (this will cost extra bandwidth) - avoid png at all cost
5) tune further to reduce CPU usage - this may require using environment 
variables which are only documented in the source code
6) tune your hypervisor, reduce context switching
etc..

> Each user instance have to run separatly in each users shell because auth with ssh which access to the executed program.
> 
> Any hints on this or is it simply not possible to run xpra with so much users on one machine?
It really depends on what your application does, how much CPU and 
graphics bandwidth it requires.
90 users is quite high.

Cheers,
Antoine

> 
> Regards
> Patrick
> 
> 
> ----------------------------------------------------------------------
> Die Firma TECHNOLIT� GmbH erhebt personenbezogene Daten zur Durchf�hrung der mit Ihnen vereinbarten Leistungen. Wir verarbeiten personenbezogene Daten gem�� den Bestimmungen der DS-GVO.
> Weitere ausf�hrliche Informationen zum Datenschutz finden Sie auf unserer Website www.technolit.de unter Datenschutz.
> Auf Wunsch �bersenden wir diese Information auch in Papierform.
> 
> TECHNOLIT� GmbH
> Industriestr. 8, 36137 Gro�enl�der
> Gesch�ftsf�hrer: Simone Lang, Stephan G�nther, Klaus Sch�nherr
> Amtsgericht Fulda, HRB 390
> 
> Diese E-Mail enth�lt vertrauliche und/oder rechtlich gesch�tzte
> Informationen. Wenn Sie nicht der richtige Adressat sind oder diese
> E-Mail irrt�mlich erhalten, informieren Sie bitte sofort den Absender
> und vernichten Sie diese Mail. Das unerlaubte Kopieren sowie
> die unbefugte Weitergabe dieser Mail ist nicht gestattet.
> 
> 
> 
> _______________________________________________
> shifter-users mailing list
> shifter-users at lists.devloop.org.uk
> https://lists.devloop.org.uk/mailman/listinfo/shifter-users
>