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Author Topic: Problem with OpenCL on Linux  (Read 486 times)

Ankkala

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Problem with OpenCL on Linux
« on: May 11, 2017, 10:36:39 AM »
The game starts up fine, but in the "Computation device" menu I can only see NativeCPU and ManagedCPU options.

I have a GTX 1080Ti and I have installed Nvidia proprietary drivers (packages nvidia-381, nvidia-opencl-icd-381, nvidia-libopencl1-381 from the Proprietary GPU Drivers PPA, https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa ). I'm running Ubuntu 16.04.

I'll be glad to provide any additional info you may need to debug this issue. Thanks a lot.

Jar

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Re: Problem with OpenCL on Linux
« Reply #1 on: May 11, 2017, 12:02:13 PM »
Sorry for the confusion. This is correct -- it should only list "NativeCPU" and "ManagedCPU." Here's an explanation from our physics developer:
Quote
"As to native vs managed, managed means the c# implementation of the nbody code while native is the c++ implementation (not user friendly names, I know), which still has managed collision-resolution parts, though. Native is generally some 3-5 times faster, and should be the default mode. The nbody code is currently being re-re-rewritten to be even more pure c++, with still better performance, while dropping managed mode entirely.

Currently we are not using the gpu for computations. We did a long time ago use OpenCL for the core of nbody, but with support for multiple platforms, and now even mobile, the pure cpu implementation won out. This is likely to change eventually, but we will not provide gpu computation any time soon.

Hope that helps explain!

Ankkala

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Re: Problem with OpenCL on Linux
« Reply #2 on: May 11, 2017, 12:26:03 PM »
I'm not sure "confusion" is the right word to describe this situation, because I have on multiple occasions seen confirmation by the developers that the game does indeed support GPU computation:

https://steamcommunity.com/app/72200/discussions/0/558747922987475606/

Quote from: Dan Dixon
Universe Sandbox , the sequel, supports GPU processing.

https://steamcommunity.com/app/230290/discussions/0/613948093895041407/

Quote from: C7
We do use OpenCL for acceleration, and we're able to utilize both CPUs and GPUs.

Needless to say, making false claims to sell your game will make your customers upset.

Edit: Not only is OpenCL support mentioned in those steam community posts that I linked, it's even pinned to this discussion forum in the Linux troubleshooting thread:

Problem : The game is running very slowly or cannot start up

This is typically due to running the game without OpenCL, which can be tricky to get setup in Linux.

...

This is ridiculous.
« Last Edit: May 11, 2017, 12:40:02 PM by Ankkala »

Jar

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Re: Problem with OpenCL on Linux
« Reply #3 on: May 11, 2017, 02:15:53 PM »
Sorry for misleading you, that certainly was not our intention. As you can see, those forum posts are more than 2 years old. We try to maintain accurate information in all of our marketing material, and I don't believe we state that we use GPU computation anywhere aside from these forum replies, which were true when written (I just removed the irrelevant information from the Linux troubleshooting post).

We are an Early Access game in active development, and features are bound to change. As our physics developer said in that quote, we once supported this, but CPU implementation proved the better path for now. Our new "Native Physics" on the CPU is actually much faster than our old GPU implementation ever was, mainly because more of the code runs on fast C++, where previously only the gravity actually ran on GPU, while everything else was on slower C#. It's possible we'll be able to move to some GPU computation again in the future, but so far it's only been an improvement on our old system.