[X2Go-User] x2go performance again

[Walid MOGHRABI]

Hi,

I'm struggling with performances too but mainly with web browser performances.
I'm on a LAN and using either 16m-jpeg (a few artifacts giving unpleasing readability on small texts but very speedy and responsive, youtube videos plays just fine but not in fullscreen) or 16m-png-jpeg (no artifact, good overall speed except for animated stuff such as videos)

I must say that I'm using it in 1920x1080 resolution in TCE mode.

The problem is not X2Go refresh performances but how some softwares interact with the X server.
In fact, I'm currently struggling with browsers and I ended with 2 kind of issues :

Xrender enabled browsers : Firefox or Epiphany.
Refresh is good but FF still tries to use 2D HW accelerated stuff with some css attributes (I discovered filter:alpha was one of them) which is then translated to software and is a CPU hog but, for "normal" workloads, it is the best compromise between features and performances (performances with youtube for example is just great)
Epiphany on the other hand is Webkit based and it has a blazingly fast Javascript engine AND render engine which works with Xrender which is not the case for most webkit based browsers.
Until now, for the workload where FF is slow (many JS + many CSS), it flies but it has a lot less feature and is somewhat buggy here and there (especially the dev tools are not working in Epiphany 3.18 which is shipped with Ubuntu 16.04 that I use).

Webkit based browsers : Chrome/Chromium, Midori and others except Epiphany
They are all very fast with JS and CSS but, the whole rendering is damn slow and there is nothing that can be done, I tried to enable xrender and/or disable gl rendering, there was nothing I could do, this is still far too slow to be really usable.

On the other hand, every other apps that conforms well with X work like a charm, even heavily gfx based stuff such as Gimp, MyPaint, Libreoffice, ....


Regards,
Walid Moghrabi

TRAVAUX.COM
BAT I - PARC CEZANNE 2 290 AVENUE GALILEE - CS 80403
13591 AIX EN PROVENCE CEDEX 3


----- Mail original ----- 

De: "Stefan Seidel" <sseidel at vub.de> 
À: x2go-user at lists.x2go.org 
Envoyé: Lundi 30 Janvier 2017 10:42:01 
Objet: [X2Go-User] x2go performance again 


Hi, 

some time ago I inquired about peoples experience with x2go in a LAN environment. I have now built a TCE live system (TFTP-only, no NFS) and a new Jessie server and I am still not very satisfied. I tried almost all available options. Here is the setup: 

1GBit/s LAN on both sides 
Host: AMD 4.4GHz 8-core CPU with 32GB RAM 
Client: Pentium D 2.8GHz, 1GB RAM, nVidia 6200 with 2 screens at 1200x1600 

I tested MATE desktop with Firefox 51 (tried XRender on/off) and Chromium 55. I usually set the browser to fill half of the screen, that mean roughly the same number of pixels as a Full-HD (1920x1080) screen. I usually open https://www.heise.de and scroll up and down a bit. 

nopack: almost the best of it all, responsiveness good, Chrome and Firefox without XRender laggy 

rfb-hextile/tight: better for small screen updates, worse for large screen updates, scrolling in Firefox with XRender active is *very* smooth 

rdp: almost identical to rfb 

adaptive: middle ground, everything is laggy but at least there's always the same amount of lag for small and big screen updates. Unacceptable though because almost all text has JPEG artifacts no matter whether the quality is set to 1, 7 or 9. Graphics like Munin graphs are really ugly. 

16m-png: good quality, mostly lag-free except Chrome and Firefox when XRender is off, becomes very unresponsive with lots of screen updates 

16m-jpeg: artifacts, speed like adaptive 


I believe nopack or rfb would give better performance if it was possible to circumvent going through SSH. I have set SSH to use arcfour (this is a trusted, isolated LAN) and performance has been slightly better. 

Is there any way of making the initial authentication and startup through SSH but then having the NX connection going directly to the client? That would save a lot of processing power! (I'm thinking similar to the "tunnel" feature for sound.) 

Regards, 

Stefan 
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