X11 performance terrible using plugin
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.
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 An alternative would be VirtualGL Altair Access (though more likely to work with PBS!) https://altair.com/access\ 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-leave@lists.schedmd.com
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 DCV (now owned by AWS but you can get licenses for on prem) https://www.ni-sp.com/products/nice-dcv
An alternative would be VirtualGL
Altair Access (though more likely to work with PBS!) https://altair.com/access\
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-leave@lists.schedmd.com
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@lists.schedmd.com
-- Hadrian Djohari Director of Advanced Research Computing, [U]Tech Case Western Reserve University (W): 216-368-0395 (M): 216-798-7490
It may or may not be an appropriate solution for your use cases, but I second using Open OnDemand and its virtual desktop. It is FAR more performant than X11 through Slurm/SSH. *Jason L. Simms, Ph.D., M.P.H.* Research Computing Manager Swarthmore College Information Technology Services (610) 328-8102 On Fri, Jun 6, 2025 at 8:40 AM Hadrian Djohari via slurm-users < slurm-users@lists.schedmd.com> wrote:
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 DCV (now owned by AWS but you can get licenses for on prem) https://www.ni-sp.com/products/nice-dcv
An alternative would be VirtualGL
Altair Access (though more likely to work with PBS!) https://altair.com/access\
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-leave@lists.schedmd.com
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@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-leave@lists.schedmd.com
Thanks for the suggestions – some interesting links to read. We already have an option to run graphical sessions from the head node using Apache Guacamole which works well, but that still requires X11 to talk to the compute nodes. We don’t have a full desktop stack on the compute nodes and just want to run individual applications. The issue isn’t network bandwidth – I can launch two graphical instances, one via ssh and the other via srun at the same time on the same compute node and ssh is great but srun is terrible. We do route through the head node (the compute nodes aren’t directly addressable) but the overall traffic on the head node is pretty modest. I’m not really sure how the X11 plugin works (assuming it’s not just doing ssh X tunnelling) to try to think what else could be limiting here. Simon. From: Jason Simms <jsimms1@swarthmore.edu> Sent: 06 June 2025 13:52 To: Hadrian Djohari <hxd58@case.edu> Cc: John Hearns <hearnsj@gmail.com>; Simon Andrews <simon.andrews@babraham.ac.uk>; slurm-users@lists.schedmd.com Subject: Re: [slurm-users] Re: X11 performance terrible using plugin CAUTION: This email originated outside of the Organisation. Please help to keep us safe and do not click links or open attachments unless you recognise the sender and know the content is safe. It may or may not be an appropriate solution for your use cases, but I second using Open OnDemand and its virtual desktop. It is FAR more performant than X11 through Slurm/SSH. Jason L. Simms, Ph.D., M.P.H. Research Computing Manager Swarthmore College Information Technology Services (610) 328-8102 On Fri, Jun 6, 2025 at 8:40 AM Hadrian Djohari via slurm-users <slurm-users@lists.schedmd.com<mailto:slurm-users@lists.schedmd.com>> wrote: Or use Open OnDemand platform for the interactive Desktop. https://openondemand.org/<https://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtp%3A%2Fotsanendemnod%2Fgro.&s=EpUt8bBKDs4r2Hlhft-LHnAqgKk> On Fri, Jun 6, 2025 at 8:37 AM John Hearns via slurm-users <slurm-users@lists.schedmd.com<mailto: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://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtw%3A%2Fwts.iw.ospcn-crm%2Fsdutpovcd-ecin%2F&s=0xITGmLDGBVZzX4ADMnCbbAoi9o> An alternative would be VirtualGL Altair Access (though more likely to work with PBS!) https://altair.com/access\<https://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtl%3A%2Fatsmrtaaco%2Fi.C5%25ssecc&s=hLyv7Imbgx1A9uZG5XigVjAQneQ> On Fri, 6 Jun 2025 at 10:42, Simon Andrews via slurm-users <slurm-users@lists.schedmd.com<mailto: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<mailto:slurm-users@lists.schedmd.com> To unsubscribe send an email to slurm-users-leave@lists.schedmd.com<mailto:slurm-users-leave@lists.schedmd.com> -- slurm-users mailing list -- slurm-users@lists.schedmd.com<mailto:slurm-users@lists.schedmd.com> To unsubscribe send an email to slurm-users-leave@lists.schedmd.com<mailto:slurm-users-leave@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<mailto:slurm-users@lists.schedmd.com> To unsubscribe send an email to slurm-users-leave@lists.schedmd.com<mailto:slurm-users-leave@lists.schedmd.com> ________________________________ This email has been scanned for spam & viruses. If you believe this email should have been stopped by our filters, click here<https://portal-uk.mailanyone.net/index.html#/outer/reportspam?token=dXNlcj1zaW1vbi5hbmRyZXdzQGJhYnJhaGFtLmFjLnVrO3RzPTE3NDkyMTQzNjI7dXVpZD02ODQyRTQ5OTNEMjZCQTUwRjUyMzNBNzA4RjFDQzM2RDt0b2tlbj0zMWVmM2VlNzAzMjgxYTc3ZTNmZmQ5ZWFjYWVhNGM1NDMzNWI1MTI4Ow%3D%3D> to report it.
Stupid reply. Reverse name resolution. But surely that would only affect the initial setup of a connection not the data stream. I suggest strace of a graphical application on a computer node. You might be able to spot where any hangs are On Fri, Jun 6, 2025, 3:57 PM Simon Andrews via slurm-users < slurm-users@lists.schedmd.com> wrote:
Thanks for the suggestions – some interesting links to read. We already have an option to run graphical sessions from the head node using Apache Guacamole which works well, but that still requires X11 to talk to the compute nodes. We don’t have a full desktop stack on the compute nodes and just want to run individual applications.
The issue isn’t network bandwidth – I can launch two graphical instances, one via ssh and the other via srun at the same time on the same compute node and ssh is great but srun is terrible. We do route through the head node (the compute nodes aren’t directly addressable) but the overall traffic on the head node is pretty modest.
I’m not really sure how the X11 plugin works (assuming it’s not just doing ssh X tunnelling) to try to think what else could be limiting here.
Simon.
*From:* Jason Simms <jsimms1@swarthmore.edu> *Sent:* 06 June 2025 13:52 *To:* Hadrian Djohari <hxd58@case.edu> *Cc:* John Hearns <hearnsj@gmail.com>; Simon Andrews < simon.andrews@babraham.ac.uk>; slurm-users@lists.schedmd.com *Subject:* Re: [slurm-users] Re: X11 performance terrible using plugin
*CAUTION:* This email originated outside of the Organisation. Please help to keep us safe and do not click links or open attachments unless you recognise the sender and know the content is safe.
It may or may not be an appropriate solution for your use cases, but I second using Open OnDemand and its virtual desktop. It is FAR more performant than X11 through Slurm/SSH.
*Jason L. Simms, Ph.D., M.P.H.*
Research Computing Manager
Swarthmore College Information Technology Services
(610) 328-8102
On Fri, Jun 6, 2025 at 8:40 AM Hadrian Djohari via slurm-users < slurm-users@lists.schedmd.com> wrote:
Or use Open OnDemand platform for the interactive Desktop.
https://openondemand.org/ <https://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtp%3A%2Fotsanendemnod%2Fgro.&s=EpUt8bBKDs4r2Hlhft-LHnAqgKk>
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://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtw%3A%2Fwts.iw.ospcn-crm%2Fsdutpovcd-ecin%2F&s=0xITGmLDGBVZzX4ADMnCbbAoi9o>
An alternative would be VirtualGL
Altair Access (though more likely to work with PBS!) https://altair.com/access\ <https://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtl%3A%2Fatsmrtaaco%2Fi.C5%25ssecc&s=hLyv7Imbgx1A9uZG5XigVjAQneQ>
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-leave@lists.schedmd.com
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@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-leave@lists.schedmd.com
------------------------------
This email has been scanned for spam & viruses. If you believe this email should have been stopped by our filters, click here <https://portal-uk.mailanyone.net/index.html#/outer/reportspam?token=dXNlcj1zaW1vbi5hbmRyZXdzQGJhYnJhaGFtLmFjLnVrO3RzPTE3NDkyMTQzNjI7dXVpZD02ODQyRTQ5OTNEMjZCQTUwRjUyMzNBNzA4RjFDQzM2RDt0b2tlbj0zMWVmM2VlNzAzMjgxYTc3ZTNmZmQ5ZWFjYWVhNGM1NDMzNWI1MTI4Ow%3D%3D> to report it.
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@lists.schedmd.com
The issue isn’t network bandwidth
Latency. The issue with X is always latency, not bandwidth. On Fri, Jun 6, 2025 at 8:57 AM Simon Andrews via slurm-users < slurm-users@lists.schedmd.com> wrote:
Thanks for the suggestions – some interesting links to read. We already have an option to run graphical sessions from the head node using Apache Guacamole which works well, but that still requires X11 to talk to the compute nodes. We don’t have a full desktop stack on the compute nodes and just want to run individual applications.
The issue isn’t network bandwidth – I can launch two graphical instances, one via ssh and the other via srun at the same time on the same compute node and ssh is great but srun is terrible. We do route through the head node (the compute nodes aren’t directly addressable) but the overall traffic on the head node is pretty modest.
I’m not really sure how the X11 plugin works (assuming it’s not just doing ssh X tunnelling) to try to think what else could be limiting here.
Simon.
*From:* Jason Simms <jsimms1@swarthmore.edu> *Sent:* 06 June 2025 13:52 *To:* Hadrian Djohari <hxd58@case.edu> *Cc:* John Hearns <hearnsj@gmail.com>; Simon Andrews < simon.andrews@babraham.ac.uk>; slurm-users@lists.schedmd.com *Subject:* Re: [slurm-users] Re: X11 performance terrible using plugin
*CAUTION:* This email originated outside of the Organisation. Please help to keep us safe and do not click links or open attachments unless you recognise the sender and know the content is safe.
It may or may not be an appropriate solution for your use cases, but I second using Open OnDemand and its virtual desktop. It is FAR more performant than X11 through Slurm/SSH.
*Jason L. Simms, Ph.D., M.P.H.*
Research Computing Manager
Swarthmore College Information Technology Services
(610) 328-8102
On Fri, Jun 6, 2025 at 8:40 AM Hadrian Djohari via slurm-users < slurm-users@lists.schedmd.com> wrote:
Or use Open OnDemand platform for the interactive Desktop.
https://openondemand.org/ <https://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtp%3A%2Fotsanendemnod%2Fgro.&s=EpUt8bBKDs4r2Hlhft-LHnAqgKk>
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://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtw%3A%2Fwts.iw.ospcn-crm%2Fsdutpovcd-ecin%2F&s=0xITGmLDGBVZzX4ADMnCbbAoi9o>
An alternative would be VirtualGL
Altair Access (though more likely to work with PBS!) https://altair.com/access\ <https://url6.mailanyone.net/scanner?m=1uNWYr-0000000Ah4a-3xXq&d=4%7Cmail%2F90%2F1749214200%2F1uNWYr-0000000Ah4a-3xXq%7Cin6i%7C57e1b682%7C10448314%7C12652688%7C6842E4993D26BA50F5233A708F1CC36D&o=%2Fphtl%3A%2Fatsmrtaaco%2Fi.C5%25ssecc&s=hLyv7Imbgx1A9uZG5XigVjAQneQ>
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-leave@lists.schedmd.com
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@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-leave@lists.schedmd.com
------------------------------
This email has been scanned for spam & viruses. If you believe this email should have been stopped by our filters, click here <https://portal-uk.mailanyone.net/index.html#/outer/reportspam?token=dXNlcj1zaW1vbi5hbmRyZXdzQGJhYnJhaGFtLmFjLnVrO3RzPTE3NDkyMTQzNjI7dXVpZD02ODQyRTQ5OTNEMjZCQTUwRjUyMzNBNzA4RjFDQzM2RDt0b2tlbj0zMWVmM2VlNzAzMjgxYTc3ZTNmZmQ5ZWFjYWVhNGM1NDMzNWI1MTI4Ow%3D%3D> to report it.
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@lists.schedmd.com
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 <hearnsj@gmail.com> Cc: Simon Andrews <simon.andrews@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$> On Fri, Jun 6, 2025 at 8:37 AM John Hearns via slurm-users <slurm-users@lists.schedmd.com<mailto:slurm-users@lists.schedmd.com>> wrote: Simon, I have had success in the past by using NICE DCV (now owned by AWS but you can get licenses for on prem) https://www.ni-sp.com/products/nice-dcv<https://urldefense.com/v3/__https:/www.ni-sp.com/products/nice-dcv__;!!NiUAmZJ8c1GNWg!RSMf2Mqfzl2OeVXskp9nf8GcVOiv3LQjhAQy2WCo4Tu_mV-bVgjkS0Q2_XhIRZC2sm-Pz8Zvgt-dFticnUCIpy8xFUhvHr4ZHT0nToE$> 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<mailto: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<mailto:slurm-users@lists.schedmd.com> To unsubscribe send an email to slurm-users-leave@lists.schedmd.com<mailto:slurm-users-leave@lists.schedmd.com> -- slurm-users mailing list -- slurm-users@lists.schedmd.com<mailto:slurm-users@lists.schedmd.com> To unsubscribe send an email to slurm-users-leave@lists.schedmd.com<mailto:slurm-users-leave@lists.schedmd.com> -- Hadrian Djohari Director of Advanced Research Computing, [U]Tech Case Western Reserve University (W): 216-368-0395 (M): 216-798-7490
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 <hearnsj@gmail.com> *Cc: *Simon Andrews <simon.andrews@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
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-leave@lists.schedmd.com
-- slurm-users mailing list -- slurm-users@lists.schedmd.com To unsubscribe send an email to slurm-users-leave@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-leave@lists.schedmd.com
participants (6)
-
Burian, John -
Davide DelVento -
Hadrian Djohari -
Jason Simms -
John Hearns -
Simon Andrews