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Multiple GPU system, multiple LE windows/apps/viewports


njord
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Hi everyone.

 

We have a simulator and 3 full hd monitors attached to it. Currently, we use 3 different computers, each running a leadwerks application and visualising the same scene on its independant monitor. The leadwerks applications on distinct pcs are synchronized through network. Of course, each LE app camera is given a certain heading degree, so that the final output image is panaromic when we look at all the monitors together.

 

However, we would like to use a single computer, and generate the same panaromic image without any performance drop. We have a test computer with 3 gpus installed using 3way SLI.

 

One way to do it I guess is to create a 5760 x 1080 pixels LE window and let it span over multiple monitors. However this way LE uses only one gpu right ? Does it at least benefit from SLI ?

What is the proper/possible way of doing this in LE ? Can we launch different apps/render windows/viewports that run on each gpu and combine them ?

 

Thanks in advance.

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LE2 supports SLI, but your SLI drivers must support it. 3way SLI however is not as fast as a single 3 times faster GPU, because there are some huge delays in the memory exchange.

I think a nVidia GTX 590 should be fast enough to run 5760x1080 at 60 FPS. You might however need to render 3 times instead, if the GPU does not natively support such resolution.

Ryzen 9 RX 6800M ■ 16GB XF8 Windows 11 ■
Ultra ■ LE 2.53DWS 5.6  Reaper ■ C/C++ C# ■ Fortran 2008 ■ Story ■
■ Homepage: https://canardia.com ■

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I would think a quad core with multiple GPUs would be able to run three instances of the program with no performance loss over a single instance. I'm not an expert on multiple GPUs, but it seems like that would be an easier way to split up the task.

My job is to make tools you love, with the features you want, and performance you can't live without.

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Question, does it need to run on 3 different display devices?

 

I use a 3840 x 1024 split over three monitors using the Matrox Digital TrippleHead2Go which makes the video card think it's plugged into one large physical display device. The Matrox device splits it into 3 DVI signals. Combined with display software that can warp your screen output to match the geometry of any curved screen...

 

Well here's a video of a guy who built his own collimated display using reflective mylar shaped by a vacuum...

 

He's using the Matrox Tripplehead on 3 projectors.

6600 2.4G / GTX 460 280.26 / 4GB Windows 7

Author: GROME Terrain Modeling for Unity, UDK, Ogre3D from PackT

Tricubic Studios Ltd. ~ Combat Helo

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I have performed some tests on my pc with i7 920@2.67GHz cpu and 3way SLI Gtx285. It seems like LE does not utilize multiple SLI connected GPUs at all. In fact, fps drops by 3x when SLI is used.

 

Anyway, my primary goal is not to enhance fps of a single app by using SLI. What I want to do is to split LE applications on different gpus, so that I can run multiple LE apps on single pc with nice fps. Thus, i tried disabling SLI, and creating LE editor windows, dragging them to each gpu's monitor. However fps dropped dramatically when the second and the third LE editors were opened, which means LE insists on using the first gpu on the system rather than also using secondary ones.

 

What are your comments lads ? Any ideas to utilize all 3 gpus ?

 

 

Test screenshots are in the attachment.

ANT is our own terrain model. OCE is a basic LE terrain created with the editor.

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Maybe you need to bridge the cards:

http://www.xtremesystems.org/forums/showthread.php?169509-Home-made-3-Way-SLI-results

 

And/or check the nVidia SLI setting:

Use the SLi indicator (in Nvidia control panel go to 3d settings on the top beside view and file and turn it on). When you run a game or anything gpu intensive the indicator will change to represent the scaling. If it changing and the green bar is pretty long then that means SLi is working.

Ryzen 9 RX 6800M ■ 16GB XF8 Windows 11 ■
Ultra ■ LE 2.53DWS 5.6  Reaper ■ C/C++ C# ■ Fortran 2008 ■ Story ■
■ Homepage: https://canardia.com ■

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Generally for single applications using SLI you need to run in fullscreen (some driver hardware combos will work for windowed applications).

But you're trying to do something different as understand, use a single GPU per application instance. As far as I'm aware OpenGL lacks control over things like this. The NVAPI might help out.

 

I saw an extension that is supposed to set GPU Affinity in OpenGL (DirectX can do this)....

http://www.opengl.org/registry/specs/NV/gpu_affinity.txt

 

 

You might also want to have a skim through nVidia SLI Best Practices document...

http://developer.download.nvidia.com/whitepapers/2011/SLI_Best_Practices_2011_Feb.pdf

6600 2.4G / GTX 460 280.26 / 4GB Windows 7

Author: GROME Terrain Modeling for Unity, UDK, Ogre3D from PackT

Tricubic Studios Ltd. ~ Combat Helo

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Of course I bridged them with SLI bridge. And in nvidia settings, I can enable/disable SLI. Unfortunately, I cannot upload screenshots rar file that is 10.5 mb .

Why not?

My job is to make tools you love, with the features you want, and performance you can't live without.

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