4 ms·

VNC has a significant performance penalty compared to network X.

by Aloha 7y ago

Spivak 7y ago
This is true but VNC doesn't exactly win any awards in the performance department in general. Sending bitmap diffs is pretty much the least efficient most naive way to do remote desktop. What VNC has going for it is that it's dead simple to implement because of that fact. X forwarding goes the complete opposite direction to pipes the whole X protocol over the network. Convenient -- yes, also dead simple to implement -- yes, actually works -- well no. You see the X ecosystem also assumes all rendering is local, that fact is just hidden in edge cases. For example Nvidia graphics work on X with an extension that both has a client and server component -- as soon as you forward X traffic that's looking for the server-side extension... crash. RDP by contrast does the right thing(tm) but also the hard thing by defining an intermediate object model which is semantic enough to kill the need to send pixels over the wire most of the time but flexible enough to allow for it when necessary.
- Aloha 7y ago
  RDP something like RDP is the correct answer - I thought it worked by effectively streaming GDI calls over the network - well that and whatever they used to replace GDI for 3D enhancements. I'd agree with you for modern applications that are not well written, I've been running X applications over the network however for 20 years or so, and outside of things like.. well 3D applications, network X works pretty well - my only real complaint was not including sound too.
  - DonHopkins 7y ago
    NCD (Network Computing Devices), who made X Terminals, came up with a sound server called "NetAudio", based on the X11 server, protocol and client library, with the graphics ripped out and sound stuck in. I used it in the early 90's to support the Unix/X11/TCL/Tk multi player version of SimCity, with a scriptable TCL/Tk audio server that could drive either /dev/audio on Sun/SGI/etc or NetAudio on NCD X Terminals. Other TCL/Tk clients like SimCity (but possibly others) communicated with it via the TCL/Tk "send" command, which bounced messages off the X server. http://www.art.net/~hopkins/Don/simcity/simcity-announcement.html http://www.art.net/~hopkins/Don/simcity/simcity-announcement... NetAudio had its problems, but basically worked. Except that it insanely mixed audio by AVERAGING (add waveforms then divide by the number of sounds) instead of adding and clipping, and I couldn't convince the NCD engineer that was the wrong way to mix sound, and to just add and clip instead, like sounds mix in the real world: When you talk over music, the music volume and the volume of your voice doesn't magically lower by half. Hopefully they've fixed that problem by now. https://donhopkins.com/home/archive/NeWS/sound-mixers.txt https://donhopkins.com/home/archive/NeWS/sound-mixers.txt It evolved into the Network Audio System (NAS): http://www.radscan.com/nas.html http://www.radscan.com/nas.html I can't say how popular it is, or if anyone actually uses it, though: The Release version is now 1.9.4 (10/07/2013).
    - Aloha 7y ago
      I've always wanted one of those NDC boxes to use - they're just kinda hard to get working on a modern network.
bdamm 7y ago
X performs better than VNC for stuff like xscreensaver, but not usually for video or applications that do dumb stuff like cute animations of internal windows opening. VNC just drops out the frames and catches up. X tends to render to perfection each graphic context call.
ken 7y ago
I’m fine with that tradeoff. For people who need network rendering, they can pay a performance penalty when they use it. For the 99% of people who 99% of the time don’t use this feature, we aren’t paying the performance (and architectural complexity) cost of this. Electron is panned by many these days for requiring an expensive network system for a local process. Why doesn’t X11 get the same scorn? Have we forgotten the days when a Mac could run a GUI in 128K while a Unix system struggled to run x11 (with no clients) in 4MB? X is heavy.
- fao_ 7y ago
  > Electron is panned by many these days for requiring an expensive network system for a local process. Why doesn’t X11 get the same scorn? Have we forgotten the days when a Mac could run a GUI in 128K while a Unix system struggled to run x11 (with no clients) in 4MB? X is heavy. If you actually properly understood both the argument you're making and the reason why most people dislike Electron and friends, then you'd not be making that argument. I'll give you the benefit of the doubt and assume you're joking.
  - DonHopkins 7y ago
    Actually, Electron (and most other web browsers) on the Mac OS/X and iOS use IOSurface to share zero-copy textures in GPU memory between the render and browser processes. Android and Windows (I presume, but don't know name of the API, probably part of DirectX) have similar techniques. It's like shared memory, but for texture memory in the GPU between separate heavy weight processes. Since simply sharing main memory between processes wouldn't be nearly as efficient, requiring frequent uploading and downloading textures to and from the GPU. Mac OS/X and iOS IOSurface: https://developer.apple.com/documentation/iosurface?language=objc https://developer.apple.com/documentation/iosurface?language... http://neugierig.org/software/chromium/notes/2010/08/mac-accelerated-rendering.html http://neugierig.org/software/chromium/notes/2010/08/mac-acc... https://github.com/SimHacker/UnityJS/blob/master/notes/IOSurface.txt https://github.com/SimHacker/UnityJS/blob/master/notes/IOSur... Android SurfaceTexture and GL_TEXTURE_EXTERNAL_OES: https://developer.android.com/reference/android/graphics/SurfaceTexture https://developer.android.com/reference/android/graphics/Sur... https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external.txt https://www.khronos.org/registry/OpenGL/extensions/OES/OES_E... https://docs.google.com/document/d/1J0fkaGS9Gseczw3wJNXvo_r-O5-SZmTlDvbgn56pdQI https://docs.google.com/document/d/1J0fkaGS9Gseczw3wJNXvo_r-... https://github.com/SimHacker/UnityJS/blob/master/notes/ZeroCopy.txt https://github.com/SimHacker/UnityJS/blob/master/notes/ZeroC... https://github.com/SimHacker/UnityJS/blob/master/notes/SurfaceTexture.txt https://github.com/SimHacker/UnityJS/blob/master/notes/Surfa...

VNC has a significant performance penalty compared to network X.

by Aloha 7y ago

VNC has a significant performance penalty compared to network X.

This is true but VNC doesn't exactly win any awards in the performance department in general. Sending bitmap diffs is pretty much the least efficient most naive way to do remote desktop. What VNC has going for it is that it's dead simple to implement because of that fact. X forwarding goes the complete opposite direction to pipes the whole X protocol over the network. Convenient -- yes, also dead simple to implement -- yes, actually works -- well no. You see the X ecosystem also assumes all rendering is local, that fact is just hidden in edge cases. For example Nvidia graphics work on X with an extension that both has a client and server component -- as soon as you forward X traffic that's looking for the server-side extension... crash. RDP by contrast does the right thing(tm) but also the hard thing by defining an intermediate object model which is semantic enough to kill the need to send pixels over the wire most of the time but flexible enough to allow for it when necessary.

Aloha 7y ago
RDP something like RDP is the correct answer - I thought it worked by effectively streaming GDI calls over the network - well that and whatever they used to replace GDI for 3D enhancements. I'd agree with you for modern applications that are not well written, I've been running X applications over the network however for 20 years or so, and outside of things like.. well 3D applications, network X works pretty well - my only real complaint was not including sound too.
- DonHopkins 7y ago
  NCD (Network Computing Devices), who made X Terminals, came up with a sound server called "NetAudio", based on the X11 server, protocol and client library, with the graphics ripped out and sound stuck in. I used it in the early 90's to support the Unix/X11/TCL/Tk multi player version of SimCity, with a scriptable TCL/Tk audio server that could drive either /dev/audio on Sun/SGI/etc or NetAudio on NCD X Terminals. Other TCL/Tk clients like SimCity (but possibly others) communicated with it via the TCL/Tk "send" command, which bounced messages off the X server. http://www.art.net/~hopkins/Don/simcity/simcity-announcement.html http://www.art.net/~hopkins/Don/simcity/simcity-announcement... NetAudio had its problems, but basically worked. Except that it insanely mixed audio by AVERAGING (add waveforms then divide by the number of sounds) instead of adding and clipping, and I couldn't convince the NCD engineer that was the wrong way to mix sound, and to just add and clip instead, like sounds mix in the real world: When you talk over music, the music volume and the volume of your voice doesn't magically lower by half. Hopefully they've fixed that problem by now. https://donhopkins.com/home/archive/NeWS/sound-mixers.txt https://donhopkins.com/home/archive/NeWS/sound-mixers.txt It evolved into the Network Audio System (NAS): http://www.radscan.com/nas.html http://www.radscan.com/nas.html I can't say how popular it is, or if anyone actually uses it, though: The Release version is now 1.9.4 (10/07/2013).
  - Aloha 7y ago
    I've always wanted one of those NDC boxes to use - they're just kinda hard to get working on a modern network.

bdamm 7y ago

X performs better than VNC for stuff like xscreensaver, but not usually for video or applications that do dumb stuff like cute animations of internal windows opening. VNC just drops out the frames and catches up. X tends to render to perfection each graphic context call.

ken 7y ago

I’m fine with that tradeoff. For people who need network rendering, they can pay a performance penalty when they use it. For the 99% of people who 99% of the time don’t use this feature, we aren’t paying the performance (and architectural complexity) cost of this. Electron is panned by many these days for requiring an expensive network system for a local process. Why doesn’t X11 get the same scorn? Have we forgotten the days when a Mac could run a GUI in 128K while a Unix system struggled to run x11 (with no clients) in 4MB? X is heavy.

fao_ 7y ago
> Electron is panned by many these days for requiring an expensive network system for a local process. Why doesn’t X11 get the same scorn? Have we forgotten the days when a Mac could run a GUI in 128K while a Unix system struggled to run x11 (with no clients) in 4MB? X is heavy. If you actually properly understood both the argument you're making and the reason why most people dislike Electron and friends, then you'd not be making that argument. I'll give you the benefit of the doubt and assume you're joking.
- DonHopkins 7y ago
  Actually, Electron (and most other web browsers) on the Mac OS/X and iOS use IOSurface to share zero-copy textures in GPU memory between the render and browser processes. Android and Windows (I presume, but don't know name of the API, probably part of DirectX) have similar techniques. It's like shared memory, but for texture memory in the GPU between separate heavy weight processes. Since simply sharing main memory between processes wouldn't be nearly as efficient, requiring frequent uploading and downloading textures to and from the GPU. Mac OS/X and iOS IOSurface: https://developer.apple.com/documentation/iosurface?language=objc https://developer.apple.com/documentation/iosurface?language... http://neugierig.org/software/chromium/notes/2010/08/mac-accelerated-rendering.html http://neugierig.org/software/chromium/notes/2010/08/mac-acc... https://github.com/SimHacker/UnityJS/blob/master/notes/IOSurface.txt https://github.com/SimHacker/UnityJS/blob/master/notes/IOSur... Android SurfaceTexture and GL_TEXTURE_EXTERNAL_OES: https://developer.android.com/reference/android/graphics/SurfaceTexture https://developer.android.com/reference/android/graphics/Sur... https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external.txt https://www.khronos.org/registry/OpenGL/extensions/OES/OES_E... https://docs.google.com/document/d/1J0fkaGS9Gseczw3wJNXvo_r-O5-SZmTlDvbgn56pdQI https://docs.google.com/document/d/1J0fkaGS9Gseczw3wJNXvo_r-... https://github.com/SimHacker/UnityJS/blob/master/notes/ZeroCopy.txt https://github.com/SimHacker/UnityJS/blob/master/notes/ZeroC... https://github.com/SimHacker/UnityJS/blob/master/notes/SurfaceTexture.txt https://github.com/SimHacker/UnityJS/blob/master/notes/Surfa...