Question about X on the arm's.

Carsten Haitzler (The Rasterman) raster at
Tue Nov 29 00:57:09 UTC 2016

On Mon, 28 Nov 2016 17:03:17 -0500 Gene Heskett <gheskett at> said:

> 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 last night was up to 3 major versions out of date.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.

that'd be simply display REFRESH. not actual rendering of content. and forget
REMOTE display over ssh over a bottleneck of a network device. forget trying to
get anything like high performance over a network connection when it comes to
display. don't even bother. it's a waste of time. if it displays at ALL - be
happy. to provide updated pixels at 60hz for a 4k display would require a
16 GIGABIT network... with NO OTHER TRAFFIC on it at all. and no network
packet/protocol overhead. so let's make that 20 gigabit. that's assuming
xputimage with 24bpp images (padded out to 32bpp as that's how xputimage
works). that does not account for bottlenecks outside the network itself (the
system at either end and it's tpc/ip stack, kernel, memcpy's etc. etc.).

> > 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
> -- 
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
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The Rasterman (Carsten Haitzler)    raster at

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