Can't debug fortran code using cuda-gdb, X11 error error: All CUDA devices are used for X11 and

I’m having trouble trying to debug a simple piece of CUDA fortran code.

I compile the code like this:

pgf90 -g test.cuf -o test

Then I run cuda-gdb test, followed by ‘run’. This is the error I get:

Starting program: /home/theory/phrkaj/Code/cuda/test 

error: All CUDA devices are used for X11 and cannot be used while debugging.

Now I’ve checked the manual for cuda-gdb 3.1 and it says this:

[indent]X11 cannot be running on the GPU that is used for debugging because the debugger

effectively makes the GPU look hung to the X server, resulting in a deadlock or crash.

Two possible debugging setups exist:

• remotely accessing a single GPU (using VNC, ssh, etc.)

• using two GPUs, where X11 is running on only on[/indent]

My question here is, is there anyway around this? Can I debug in emulation-mode? I wasn’t having any problem running the code, but when trying to debug is I get this X11 error.

Thanks for the help

PS. I’ve attached the source code as a .txt file, since this forum won’t let me attach .cuf files.
test.txt (671 Bytes)

As the release notes say, interactive debugging with cuda-gdb requires a dedicated GPU without a display manager running on it. That means no X11 on the device you use for debugging. If you only have one device, you have to stop X11 and either use a TTY session or something like ssh or Nx remotely from another machine. To the best of my knowledge the requirement is non-negotiable.

You most probably can debug in PGI’s emulation mode, but you don’t need cuda-gdb for that. Just use the host debugger and interface of your choice.

cuda-gdb does not support Fortran debugging. On using the debugger with an active desktop please search for “usage scenarios” in http://developer.download.nvidia.com/compute/cuda/3_2_prod/toolkit/docs/Mac_User_Guide_gdb_Preview.pdf which was updated recently for the mac preview release of cuda-gdb.