Using OpenCL on CUDA 5.0

Accelerated Computing CUDA CUDA Setup and Installation
1

Hello there. I’m using Ubuntu 12.04 and CUDA 5.0.

I was able to find the OpenCL headers, but not the library. A system-wide search for the terms “opencl” and “ocl” only returned a empty folder, namely, /etc/OpenCL/vendors.

Any ideas?

2

It was my mistake on the find command. As I installed the repo driver, I could find the library on /usr/lib/nvidia-current.

Yet, when I run any program using OpenCL, only the Intel platform is detected. Could it be an Optimus-related issue?

3

I don’t think it’s Optimus since it generally doesn’t work at all under Linux. Here a few things to check:

  • To check if the nvidia kernel module is loaded you can use "lsmod | grep nvidia". If something like "nvidia 9367660 106" is shown continue.
  • If the driver detected your GPU you should find some information under /proc/driver/nvidia/gpus.
  • Do you have nouveau still on your system? If yes get rid of it.
  • Do you have a nvidia.icd file in /etc/OpenCL/vendors? It's contents should be the name of the library exporting the necessary symbols expected by the icd loader. For me (driver version 310.14) that's "libnvidia-opencl.so.1" (without the quotes). With previous drivers it would be "libcuda.so". You can check the version with "modinfo --field version nvidia" or "cat /proc/driver/nvidia/version".

To make sure that your code is not the problem you could use clInfo:
wget http://graphics.stanford.edu/~yoel/notes/clInfo.c
gcc -w -lOpenCL clInfo.c -o clinfo
./clinfo

If that didn’t help you could check /var/log/Xorg.0.log to see if the driver is having any problems.

You could also just run “sudo nvidia-bug-report.sh” as described here (https://devtalk.nvidia.com/default/topic/522835/linux/if-you-have-a-problem-please-read-this-first/) and attach the resulting nvidia-bug-report.log.gz.

4

kugeleck,

Thank you for your reply. Looks like I did not have nvidia.icd on /etc/OpenCL/vendors. I could find it on /etc/share/nvidia-current. Even after copying, it did not work. After comparing with intel’s, I could notice that just the name of the library wasn’t enough. Probably because LD_LIBRARY_PATH doesn’t contain the correct folder. Then, changing the file to

/usr/lib/nvidia-current/libnvidia-opencl.so.1

did work.

As I’m using bumblebee to use the optimus technology, I need to run the command with optirun. Besides that, everything works perfectly.

5

Glad to hear that it’s working now.

I usually install everything OpenCL related under /opt/OpenCL and then setup environment variables in /etc/profile.d/opencl.sh. For Nvidia it looks like this:

export PATH="$PATH:/opt/OpenCL/sdk/nvidia/5.0/bin"

To make the libs available I then add opencl.conf under /etc/ld.so.conf.d containing:

/opt/OpenCL/sdk/nvidia/5.0/lib64