I third the suggestion to use OnDemand. FWIW, OnDemand uses VNC under the hood, so performance is identical to that, and the user experience is much, much better. Plain VNC is marginally easier for the administrator to set up: choose if you prefer doing a bit more administration work or (a little or a lot, depending on sophistication of your base) more user-support work.
To answer the original question, which most people have avoided.... The problem is that X11 is a protocol with a high number of latency-sensitive messages being exchanged, even for a simple action such as a single button click (let alone a menu). It was never really designed to run across complex networks as we do today. Every time you add a hop (a slurm one in which case) that latency increases and given the large number of messages involved, it easily becomes noticeable. Here slurm could be the last straw, but it's possible that the vast majority of latency is introduced by other network hops. In our network setup, even just regular ssh with X-tunneling to the head node results in an unusable latency for X applications running on the head node itself (let alone on the compute nodes). OnDemand (web server on the head node, used also as a jump to the compute nodes since they are inaccessible from the outside) works just fine despite the additional network hoops. If you are *really* stuck with plain X-tunneling, there isn't much you can do, other than a careful study on all the sources of latency and a careful, and tedious work attempting to limit them. Maybe some tracerouting/pinging can at least give you a first rough idea on what this would entail. You may be lucky and there is a single large source which you could easily mitigate, but in my experience it's always been a death by papercuts scenario. On Fri, Jun 6, 2025 at 7:09 AM Burian, John via slurm-users < slurm-users@lists.schedmd.com> wrote: > We’ve been using TurboVNC. > > > > *From: *Hadrian Djohari via slurm-users <slurm-users@lists.schedmd.com> > *Date: *Friday, June 6, 2025 at 8:41 AM > *To: *John Hearns <hear...@gmail.com> > *Cc: *Simon Andrews <simon.andr...@babraham.ac.uk>, > slurm-users@lists.schedmd.com <slurm-users@lists.schedmd.com> > *Subject: *[slurm-users] Re: X11 performance terrible using plugin > > Or use Open OnDemand platform for the interactive Desktop. https: > //openondemand. org/ On Fri, Jun 6, 2025 at 8: 37 AM John Hearns via > slurm-users <slurm-users@ lists. schedmd. com> wrote: Simon, I have had > success in the past by using NICE > > ZjQcmQRYFpfptBannerStart > > *This Message Is From an External Sender * > > This message came from outside your organization. > > Search “email warning banner” on ANCHOR for more information > > > <https://us-phishalarm-ewt.proofpoint.com/EWT/v1/NiUAmZJ8c1GNWg!ZvBtiKipoZRgNVzWzQHny3GH0K5qbFXYIvCOhZROuXbz07DxA7KwCJEX_mZu6ikJXhwYlTr3zXFQBmK2Rhi1S4FyZp8fC-x3lK4qoyufagjND6t7-20dlVeDyCbByk3Q2bjxb24$> > > Report Suspicious > <https://us-phishalarm-ewt.proofpoint.com/EWT/v1/NiUAmZJ8c1GNWg!ZvBtiKipoZRgNVzWzQHny3GH0K5qbFXYIvCOhZROuXbz07DxA7KwCJEX_mZu6ikJXhwYlTr3zXFQBmK2Rhi1S4FyZp8fC-x3lK4qoyufagjND6t7-20dlVeDyCbByk3Q2bjxb24$> > > > > > > ZjQcmQRYFpfptBannerEnd > > Or use Open OnDemand platform for the interactive Desktop. > > https://openondemand.org/ > <https://urldefense.com/v3/__https:/openondemand.org/__;!!NiUAmZJ8c1GNWg!RSMf2Mqfzl2OeVXskp9nf8GcVOiv3LQjhAQy2WCo4Tu_mV-bVgjkS0Q2_XhIRZC2sm-Pz8Zvgt-dFticnUCIpy8xFUhvHr4ZsSsptVY$> > > > > On Fri, Jun 6, 2025 at 8:37 AM John Hearns via slurm-users < > slurm-users@lists.schedmd.com> wrote: > > Simon, I have had success in the past by using NICE DCV (now owned by AWS > but you can get licenses for on prem) > https://www.ni-sp.com/products/nice-dcv > <https://urldefense.com/v3/__https:/www.ni-sp.com/products/nice-dcv__;!!NiUAmZJ8c1GNWg!RSMf2Mqfzl2OeVXskp9nf8GcVOiv3LQjhAQy2WCo4Tu_mV-bVgjkS0Q2_XhIRZC2sm-Pz8Zvgt-dFticnUCIpy8xFUhvHr4ZHT0nToE$> > > An alternative would be VirtualGL > > Altair Access (though more likely to work with PBS!) > https://altair.com/access\ > <https://urldefense.com/v3/__https:/altair.com/access*5C__;JQ!!NiUAmZJ8c1GNWg!RSMf2Mqfzl2OeVXskp9nf8GcVOiv3LQjhAQy2WCo4Tu_mV-bVgjkS0Q2_XhIRZC2sm-Pz8Zvgt-dFticnUCIpy8xFUhvHr4Z8bj_di0$> > > > > > > > > On Fri, 6 Jun 2025 at 10:42, Simon Andrews via slurm-users < > slurm-users@lists.schedmd.com> wrote: > > On our cluster we’ve noticed that if we use the native x11 slurm plugin > (PrologFlags=x11) then X applications work, but are really slow and > unresponsive. Even opening menus on graphical application is painfully > slow. > > > > On the same system if I do a direct ssh connection with ssh -YC from the > head node the same applications are quick and responsive. > > > > Any suggestions for what might be causing this, and how I can get the > native x11 to have the same responsiveness as a direct ssh connection? > > > > Many thanks > > > > Simon. > > > -- > slurm-users mailing list -- slurm-users@lists.schedmd.com > To unsubscribe send an email to slurm-users-le...@lists.schedmd.com > > > -- > slurm-users mailing list -- slurm-users@lists.schedmd.com > To unsubscribe send an email to slurm-users-le...@lists.schedmd.com > > > > -- > > Hadrian Djohari > Director of Advanced Research Computing, [U]Tech > Case Western Reserve University > (W): 216-368-0395 > (M): 216-798-7490 > > -- > slurm-users mailing list -- slurm-users@lists.schedmd.com > To unsubscribe send an email to slurm-users-le...@lists.schedmd.com >
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