[mythtv-users] mythfrontend performance over x11vnc

[Ram Ramesh]

On 3/16/22 16:38, Dave Ulrick wrote:
> I have two Intel NUC boxes that I use to run mythfrontend under Fedora 
> 34. I like to do most administration remotely using x11vnc. (That way 
> I can use an ergonomic keyboard and sit in front of a monitor that's 
> within good viewing distance...much more comfortable than using a 
> wireless keyboard while trying to look at a distant TV.)
>
> Sometimes remote control is nearly as fast as it would be to control 
> the box locally--the OpenGL fade effects look pretty good and 
> recording playback is very close to optimal--but other times it's 
> extremely slow: > 1 second delay for response to any keystroke. Once 
> the slow behavior kicks in, it persists from one x11vnc session to 
> another until mythfrontend is restarted or the box's monitor (TV) is 
> turned on.
>
> Note that the x11vnc slowness occurs even if I implement the solutions 
> recommended for slowness issues: set -noxdamage, disable desktop 
> compositing, disable vblank, etc..
>
> Just now I figured out how this issue occurs:
>
> 1. The remote PC's monitor is turned off.
> 2. The screensaver on the remote PC has blanked the screen.
> 3. x11vnc is invoked.
> 4. The VNC viewer connects and shows a blank screen.
> 5. Pressing a key brings the screen to life but from then on 
> mythfrontend is very slow via x11vnc.
>
> My guess as to what's going on is that when the PC turns off the 
> monitor, the X server loses sync so x11vnc falls back on a 
> timeout-driven refresh scheme.
>
> I have come up with a simple solution.
>
> In my use case, I only have a monitor--that is, an HDTV switched to an 
> HDMI input--turned on when I'm watching MythTV content. Otherwise, the 
> monitor is turned off. Therefore, there's no need to run a screen 
> saver. I didn't find a quick way to stop the screensaver 
> (xfce4-screensaver) from running so I just went ahead and removed it 
> from the boxes (dnf remove xfce4-screensaver).
>
> Since removing the screensaver, the screen hasn't blanked so 
> mythfrontend has retained fast performance over VNC.
>
> Hope this helps someone out...
>
> Dave
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Interesting. Without knowing this dependency, I have screensaver 
uninstalled because the only monitor is TV and it is off in my case when 
I am not actively using it. However, my x11vnc is always slow from one 
machine and always reasonable from another machine (connected to two 
different TVs)

I noticed that when I boot without turning on TV, my X is 640x480. I 
have to do xrandr --fb 1920x1080 to get it big or turn on the TV. When 
this happens I have seen slowness also. So best to turn on TV, remove 
screensaver and boot the PC.

Regards
Ramesh