currently my graphics controller is equipped with two Nvidia P4000 cards connected to a LED Wall Display with a total resolution of 9600x3240 pixels connected to the 2 Nvidia P4000 cards with 6 outputs (3 for each P4000 card) with different resolutions. It is not possible to create a Mosaic since the 6 areas do not have the same graphic resolution. Unfortunately, when a video is displayed, the lack of Synchronism is visible when it covers two or more areas managed by two outputs of the P4000 cards. The solution could be Nvidia Quadro Sync II but does it also work without activating Mosaic?
you canât really get sync for screens using a different resolution :-(.
Quadro sync as well as Mosaic (with sync) depend on running all screens with the same resolution and refresh rate, so exact same timing.
is there no way to split up your wall symmetrically between all 6 (or more) outputs?
yes it is possible but with 24k resolution (11,520 x 4320). In practice 6 outputs with 4k resolution each.
Can you confirm that this resolution can be supported?
Thank you
using EXACTLY same sinks(Displays)=timings across all outputs, YES, this resolution will be supported. Depending on your content/workload, pls be aware these are a lot of pixels to render for each GPU, and performance may vary, and: P4000s are not highest end GPUs, as well as not latest generation GPUsâŠ
Also for âjustâ video display, even compressed, this is a heavy stream to be fluently processed from storage system, via PCIe bus and system memory onto GPUsâŠ
If you try your workload today, at a lower resolution Mosaic, even just single GPU Mosaic, what performance are you seeing, where are your bottlenecks?
To avoid potentially visible artifacts at the edge between the 2x GPUs, you would need to add a Quadro Sync II card, to enable the Mosaic to be a syncâd Mosaic. (no difference in settings: auto-detecting presense of that sync card, Mosaic creation process will keep the same, just be ending up with a syncâd Mosaic thenâŠ)
hope this helpsâŠ
regards
-Frank
Thanks for the quick reply :)
Infact, an nVidia Quadro SyncII is already installed to resolve the lack of synchronism. Keep in mind that 8 videos are currently being displayed (4 with 38402160 resolution and 4 with 19201080 resolution) using dedicated acquisition cards so as not to burden the GPUs of the two nVidia P4000 cards (physically connect each with 3 video distributors each with resolution 3840*2160).The problem is because occasionally a video window frizzes and by disabling the Mosaic it would seem that the problem does not recur but the problem of the lack of synchronism remains.
Freeze should be a completely independend problem, to be debugged and solved reallyâŠ
Mosaic is the technology to combine the desktop real estate of more than a single screen, and make multiple screens show as a single desktop to the OS and all applications. So you can use large screens/projections as if they where just a single desktop. For a single GPU, or with the sync card across more than one GPU, Mosaic also comes with sync, makes sure all outs/GPUs display the same frame (basically, because only a single thread is running across all outs of the Mosaic).
Sync alone you CAN use with individual, non-mosaicâd displays as well, but then each screen is a separate desktop, apps see multiple desktops, and maximizing across more than a screen is not really possible, needs manual re-sizing of each windowâŠ
For usecases, where multiple applications/videos/views are displayed, and typically would NOT cross a screen border, each screen can stay its own desktop, but they can all be syncâd. Youâd then NOT use the Mosaic function and UI at all, but just the Sync function/UI, assigning one screen to be sync master, and all other be sync clients, and they all will run scanout in step. so a single window spanning 2 desktops will not show artifactsâŠ
IF you needed sync between 2 applications (views of basically the same application), the application needs to make use of our Sync API, to ensure all threads wait for the busiest one to message, âread for swapping to the next frameâ, so then they ALL swap to show the next frame in stepâŠ
Thanks for the quick response.
Provided that the graphics outputs have the same resolution (e.g. 3280*2160) with 2 P4000 cards and 1 Quadro Sync II card having an MS Windows 10 operating system, is there a limit to the resolution that Quadro Sync can manage? In the example with 2 x P4000 and 1 x Quadro Sync, what maximum resolution can I have?
Thank you
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The critical limit in Windows is the OSâ buffers size, which still is limited to 16k pixels :-(. So in Windows, canât go beyond 16k any dimension of the desktop!!
Our GPUs could do bigger, so larger desktop is actually supported in Linux.
Performace will always be a challenge, Mosaic is NOT a load separator/distibutor for a single thread workload onto multiple GPUs, its basically making all GPUs do ALL the work, but show only the part they are configured to send to a screen⊠[so a 4x4 is same speed when run from a single GPU, 2x or even 4x GPUs!]
We have experimented with 8x GPUs, 2x Sync cards, so 32x outputs, lower res, so not hitting the 16k limit, but Windows is behaving âunhappyâ with like 32x screens attached, and a large single desktop⊠:-(. Windows desktop manager maxing out a single CPU core, time for setting up a mode growing exponential, GUI struggling with to many âentriesâ⊠wouldnât be confidently suggesting such for a professional installation!
There is no HARD limit, it gradually becomes âtrickyâ, so we always need to ask for giving it a try with your own setup and workload. We do HAVE customers with such large Mosaic setups, obviously NOT rendering most heavy 3D scene in realtime, but like more 2D, slowly changing âstatus walls / controll roomsâ - it works!
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ok thanks for the reply and have a good weekend
Best Regards
Pio Montinovo
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