I have done a lot of remote desktop-related work, and there's a few things to know:
The Xrdp stack indeed uses VNC as a fallback, which is rather slow. This doesn't help.
Modern browsers use GPU acceleration to render both their UIs and web pages. When running it on on the X11->VNC->RDP combination this also incurs the penalty of having to do software rendering of what's essentially now OpenGL-based cruft.
The way MS (and Citrix) manged to make RDP (and ICA) fast, is done using several means:
- instead of VNC over TCP, it uses h.264 over UDP nowadays. H.264 has hardware acceleration in pretty much anything out there, so it's often vastly faster than encoding JPEG chunks and shoving them down a line. It also allows graceful degradation due to it being sent over UDP and the stream being fault-tolerant
- when possible, Windows uses the H.264 capabilities of your GPU, so in effect, you're not doing software rendering anymore. We're currently at a point where you can play last years' AAA games over RDP.
- legacy RDP also transmitted GDI calls, and these were rendered locally. That's why FreeRDP contains quite a complete implementation of Windows' GDI because instead of rendering it server side and passing through the image data, the UI API calls are passed through and the image is rendered locally.
TL;DR, Linux runs about two decades behind in innovation on remote desktop rendering because it never had a _real_ need for it.
/y
-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Patrik Schindler
Sent: 06 April 2020 16:34
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: P9, Linux and RDP like desktop virtualization
Hello Nathan,
Am 06.04.2020 um 16:30 schrieb Nathan Andelin <nandelin@xxxxxxxxx>:
My understanding is that Windows RDP only supports a single session, while I suspect the Linux products support multiple.
What exactly is a "session" according do your definition? When I open up a RDP Client and connect to a Windows Terminal Server, there may be multiple users active at once, plus mine.
Frank Soltis has remarked on numerous occasions that *nix was fundamentally designed as a single-user operating system.
Maybe you're referring to
https://en.wikipedia.org/wiki/History_of_Unix
"At this stage [around 1970], the new operating system was a singletasking operating system, not a multitasking one such as Multics."
Apparently, it's not clear when UNIX adopted multi-tasking and multi-user capability. But if Frank refers to this 50 year old roots, to me it's the same when people in here rage that IBM i on POWER is not the AS/400.
Perhaps your testing confirms that.
No. His testing confirms either that the conversion of the XServer's remote protocol abilities to Remote Desktop Protocol sucks, or that the Browser's Code isn't really fast in PPC, as described in a former message.
If I remember right, the RDP Server components (for Xrdp) use VNC as a translational common protocol, and VNC *is* very slow. It's good because of platform independence and for remote service but I can't imagine to do serious work with it as transport protocol.
Just consider the overhead of hosting multiple Linux sessions on a single server.
It's less overhead than using multiple servers with single users. It's mostly the same as with Windows Terminal Services. What overhead are you referring to?
:wq! PoC
PGP-Key: DDD3 4ABF 6413 38DE -
https://www.pocnet.net/poc-key.asc
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