Dear X2Go users,
I'm working on optimizing resource use of a largish-number of sessions. I made a few optimizations, e.g., disabling xscreensaver, but there were a few things I couldn't figure out on my own. Is someone here able to help?
Does X2Go do its desktop rendering on the server's GPU? That is, in building a server to support X2Go sessions, should I buy a fancy graphics card when trying run many sessions; or alternatively multiple core CPU's? If GPU matters, does it matter whether the card is of the GeForce vs. Quadro variety?
Does reducing colour depth have any substantive effect on the CPU/GPU/bandwitdth burden on the server? My users don't really need more than thousands of colours. I know this and JPEG quality can be adjusted client-side, but when I played with these settings, it didn't seem to impact server-side bandwidth (which continued to hover around 1Mbit per client even with just a few colours). Should I be adjusting this in the LXDE startup settings instead?
Is it fair to estimate that I need about 1Gb of RAM per client (just to load the desktop) just to load LXDE as the desktop?
Cheers, Jordan
Jordan Poppenk, Ph.D. Canada Research Chair in Cognitive Neuroimaging Department of Psychology and Centre for Neuroscience Studies Queen's University http://popmem.com 613-533-6009
On 09.02.2016 08:41 AM, Jordan Poppenk wrote:
- Does X2Go do its desktop rendering on the server's GPU? That is, in building a server to support X2Go sessions, should I buy a fancy graphics card when trying run many sessions; or alternatively multiple core CPU's? If GPU matters, does it matter whether the card is of the GeForce vs. Quadro variety?
Currently no, not at all.
- Does reducing colour depth have any substantive effect on the CPU/GPU/bandwitdth burden on the server? My users don't really need more than thousands of colours. I know this and JPEG quality can be adjusted client-side, but when I played with these settings, it didn't seem to impact server-side bandwidth (which continued to hover around 1Mbit per client even with just a few colours). Should I be adjusting this in the LXDE startup settings instead?
In theory, yes. A lower color depth normally translates to smaller images in size, but of course the general compression ratio achieved by the algorithm - which is also based on properties of the raw image data - might make this point moot (especially if the image doesn't actually contain a big variety of colors.)
So that question is actually quite difficult to answer definitely, "it depends."
- Is it fair to estimate that I need about 1Gb of RAM per client (just to load the desktop) just to load LXDE as the desktop?
1 GB sounds high for LXDE, but I have never measured this. Maybe others did. Still, the problem here, too, is that the answer is: "it depends." For instance, consider Java-based applications: these use separate VMs for each invokations and do not share any internal state, so the individual footprint is high. Compare that to, for instance, KDE(4), which as far as I know does a decent job of sharing libraries - hence only the first started session will have a huge impact, with subsequent sessions adding less to the global memory footprint (not "nothing", of course, because only libraries are shared, no actual program data.)
Mihai
Dear Mihai,
Thanks for your quick reply! It sounds like switching to KDE is likely a good step for saving on resources. As for colour depth, it sounds like it may not have much effect on bandwidth. But how about server CPU usage - is this a demanding part of the server's contribution?
Cheers, Jordan
Jordan Poppenk, Ph.D. Canada Research Chair in Cognitive Neuroimaging Department of Psychology and Centre for Neuroscience Studies Queen's University http://popmem.com 613-533-6009
On 2016-02-09, 7:12 AM, "Mihai Moldovan" <ionic@ionic.de> wrote:
On 09.02.2016 08:41 AM, Jordan Poppenk wrote:
- Does X2Go do its desktop rendering on the server's GPU? That is, in building a server to support X2Go sessions, should I buy a fancy graphics card when trying run many sessions; or alternatively multiple core CPU's? If GPU matters, does it matter whether the card is of the GeForce vs. Quadro variety?
Currently no, not at all.
- Does reducing colour depth have any substantive effect on the CPU/GPU/bandwitdth burden on the server? My users don't really need more than thousands of colours. I know this and JPEG quality can be adjusted client-side, but when I played with these settings, it didn't seem to impact server-side bandwidth (which continued to hover around 1Mbit per client even with just a few colours). Should I be adjusting this in the LXDE startup settings instead?
In theory, yes. A lower color depth normally translates to smaller images in size, but of course the general compression ratio achieved by the algorithm - which is also based on properties of the raw image data - might make this point moot (especially if the image doesn't actually contain a big variety of colors.)
So that question is actually quite difficult to answer definitely, "it depends."
- Is it fair to estimate that I need about 1Gb of RAM per client (just to load the desktop) just to load LXDE as the desktop?
1 GB sounds high for LXDE, but I have never measured this. Maybe others did. Still, the problem here, too, is that the answer is: "it depends." For instance, consider Java-based applications: these use separate VMs for each invokations and do not share any internal state, so the individual footprint is high. Compare that to, for instance, KDE(4), which as far as I know does a decent job of sharing libraries - hence only the first started session will have a huge impact, with subsequent sessions adding less to the global memory footprint (not "nothing", of course, because only libraries are shared, no actual program data.)
Mihai
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Jordan Poppenk -
Mihai Moldovan