[FreeNX-kNX] NX performance issue

[Fabian Franz]

> > Yes, I thought more of: running it on the same host, where 
> > bandwidth and latency should not matter.
> 
> In this mode, the frame rate is limited to about 15-17 fps.  So it is a
> bottleneck, but not as much as nxproxy (see below.)

Okay.

> > What about the pure nxproxy <-> nxproxy connection, where you 
> > have compression but no roundtrip suppression? Did you have 
> > the same fast then slow effect?
> 
> Well, since nxproxy doesn't compress images, I can't get a true apples to
> apples comparison by eliminating nxagent.  But I did connect two proxies
> on
> the same host as you suggested, and I observe that the maximum frame rate
> I
> can get out of that configuration is 7 fps. 

Uh, okay, so now lets try with compressing images:

- Connect two nxproxies directly together with compression via link modem setting, like:

remote $ LD_LIBRARY_PATH=/usr/NX/lib DISPLAY="nx/nx,link=modem:1" /usr/NX/bin/nxagent -B :1

local $ LD_LIBRARY_PATH=/usr/NX/lib/ /usr/NX/bin/nxproxy -S remote:1

remote $ DISPLAY=:1 vgl glxgears

> I don't observe the
> fast-then-slow behavior, but regardless, it appears as if the proxy is the
> primary bottleneck.  That is unfortunate, because it means that I can't
> bypass the performance issue by implementing a compressed PutImage()
> extension in nxagent.

First try again with compressing images and stream, but if that really is the case, then yes it seems so ...

What about CPU usage at the 7 fps?

> 
> I will send a message to the NX developers and see if they have any ideas.

Okay.

cu

Fabian