Question about X on the arm's.

[Antoine Martin]

On 29/11/16 05:03, Gene Heskett wrote:
> On Monday 28 November 2016 13:12:03 Alan Coopersmith wrote:
> 
>> On 11/27/16 04:29 PM, Gene Heskett wrote:
>>> Okay Alan, I've had 3 or 4 folks over the last 36 hours claim that X
>>> is its own forwarding agent, why am I even using ssh? saying I'm not
>>> needing ssh at all.
>>
>> X can connect directly, but without the encryption & compression that
>> ssh adds when it acts as the forwarding agent.  ssh has been the
>> modern recommended solution for years - all major distros have started
>> X with "-nolisten tcp" for over a decade, and recent versions of Xorg
>> made that the default, such that you need to go specify "-listen tcp"
>> to enable the old direct TCP connection method now if you want to
>> avoid ssh.
>>
>>> So, where can I find the definitive tut on doing this because our
>>> attempts are failing?  What I was able to find on the xorg web pages
>>> last night was up to 3 major versions out of date.  I need a tut
>>> that deals with X11R7 and up.  Is there such a thing?  My google-fu
>>> is failing me.
>>
>> Our recommendation for X11R7 remote connections is "Use SSH X11
>> Forwarding."
>>
> Which works but at very lethargic speeds. 3, 4 frames a second.  I need 
> 20 or more. This odroid64, with at least 3 gpu's is said to be able to 
> do a 4k display at 60 frames a second.
As other have pointed out, SSH will add some latency.
On top of that, many applications will use synchronous X11 calls which
will just kill your framerate. Try an X11 proxy to decouple the client
applications from the X11 server.
ie: (shameless plug), from your client:
xpra start ssh:ARMSERVER --start=xterm
(you will probably need to tune it for low power CPUs like arm, ie: turn
off compression)

Cheers
Antoine



> 
>> Unfortunately, so few people are willing to help write X11 docs that
>> there isn't a whole lot of stuff written since the X Consortium
>> stopped paying doc writers in the mid 90's.
> 
> Yikes! NDW I cannot find uptodate docs & tuts.
> 
> Thanks Alan, I appreciate the candor.
> 
> Cheers, Gene Heskett
>