CUDA with Optimus in Linux, root only?

Accelerated Computing CUDA CUDA Programming and Performance
1

Hi, I’m using a laptop with a GeForce GT 525M card in Ubuntu 10.04. I can only use the Intel card for display, of course, due to the Optimus technology.

I installed the developer drivers, toolkit and SDK code samples for CUDA. However, at the first, only ‘root’ can run the CUDA-enabled applications, e.g. deviceQuery. ONLY after that, normal users are able to run the CUDA-enabled apps. I used ‘lsmod’ to see whether new modules were added in a run launched by a root. But nothing new was found. Can anyone explain this, or give me a workaround to let normal users run the CUDA-enabled apps without a first execution by root?

Thank you in advance!

2

It has been a long time! I found something interesting, but it’s still a problem.

Before executing a CUDA program as a root, I can not find any nVidia devices on my laptop.

root@ubuntu64:~# ll /dev/nv*

ls: cannot access /dev/nv*: No such file or directory

After executing a CUDA program as a root, e.g. deviceQuery, two new nVidia devices will appear.

root@ubuntu64:~# ll /dev/nv*

crw-rw-rw- 1 root root 195, 0 2011-06-14 14:29 /dev/nvidia0

crw-rw-rw- 1 root root 195, 255 2011-06-14 14:29 /dev/nvidiactl

Since normal users can not modify /dev, and there is no nVidia devices until root executes a CUDA program, normal users can NEVER run a CUDA application before a root’s execution.

Is’t possible to add those devices at the start of the system, or just let normal users be able to add those devices?

3

It has been a long time! I found something interesting, but it’s still a problem.

Before executing a CUDA program as a root, I can not find any nVidia devices on my laptop.

root@ubuntu64:~# ll /dev/nv*

ls: cannot access /dev/nv*: No such file or directory

After executing a CUDA program as a root, e.g. deviceQuery, two new nVidia devices will appear.

root@ubuntu64:~# ll /dev/nv*

crw-rw-rw- 1 root root 195, 0 2011-06-14 14:29 /dev/nvidia0

crw-rw-rw- 1 root root 195, 255 2011-06-14 14:29 /dev/nvidiactl

Since normal users can not modify /dev, and there is no nVidia devices until root executes a CUDA program, normal users can NEVER run a CUDA application before a root’s execution.

Is’t possible to add those devices at the start of the system, or just let normal users be able to add those devices?

4

See the release notes for instructions.

5

See the release notes for instructions.

6

Thanks a lot, Tera!

find those in the release notes (http://developer.download.nvidia.com/compute/cuda/2_3/toolkit/docs/cudatoolkit_release_notes_linux.txt).

o In order to run CUDA applications, the CUDA module must be
loaded and the entries in /dev created. This may be achieved
by initializing X Windows, or by creating a script to load the
kernel module and create the entries.

An example script (to be run at boot time):

#!/bin/bash

modprobe nvidia

if [ “$?” -eq 0 ]; then

Count the number of NVIDIA controllers found.

N3D=/sbin/lspci | grep -i NVIDIA | grep "3D controller" | wc -l
NVGA=/sbin/lspci | grep -i NVIDIA | grep "VGA compatible controller" | wc -l

N=expr $N3D + $NVGA - 1
for i in seq 0 $N; do
mknod -m 666 /dev/nvidia$i c 195 $i;
done

mknod -m 666 /dev/nvidiactl c 195 255

else
exit 1
fi

7

Thanks a lot, Tera!

find those in the release notes (http://developer.download.nvidia.com/compute/cuda/2_3/toolkit/docs/cudatoolkit_release_notes_linux.txt).

o In order to run CUDA applications, the CUDA module must be
loaded and the entries in /dev created. This may be achieved
by initializing X Windows, or by creating a script to load the
kernel module and create the entries.

An example script (to be run at boot time):

#!/bin/bash

modprobe nvidia

if [ “$?” -eq 0 ]; then

Count the number of NVIDIA controllers found.

N3D=/sbin/lspci | grep -i NVIDIA | grep "3D controller" | wc -l
NVGA=/sbin/lspci | grep -i NVIDIA | grep "VGA compatible controller" | wc -l

N=expr $N3D + $NVGA - 1
for i in seq 0 $N; do
mknod -m 666 /dev/nvidia$i c 195 $i;
done

mknod -m 666 /dev/nvidiactl c 195 255

else
exit 1
fi