Print a list of free CUDA devices on screen. This is useful to select a free GPU in a job submission script.

get_free_cuda_devices.c

/* ======================================================================
   Copyright (2013) Lars Pastewka

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
  
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   GNU General Public License for more details.
  
   You should have received a copy of the GNU General Public License
   along with this program. If not, see <http://www.gnu.org/licenses/>.
   ====================================================================== */

#include <stdio.h>
#include <stdlib.h>

#include <nvml.h>

#define NVML(x)  { nvmlReturn_t ret = x; if (ret != NVML_SUCCESS) { printf("NVML error in line %i: %s\n", __LINE__, nvmlErrorString(ret)); \
exit(8); } }

int main(int argc, char *argv)
{
  unsigned int i, n;

  NVML( nvmlInit() );

  NVML( nvmlDeviceGetCount(&n) );

  if (n < 0 || n > 32) {
    printf("nvmlDeviceGetCount returned %i. This does not make sense.\n", n);
    exit(9);
  }

  for (i = 0; i < n; i++) {
    nvmlDevice_t dev;

    unsigned int num_procs = 32;
    nvmlProcessInfo_t procs[32];

    NVML( nvmlDeviceGetHandleByIndex(i, &dev) );
    NVML( nvmlDeviceGetComputeRunningProcesses(dev, &num_procs, procs) );

    if (num_procs < 1) {
      printf("%i\n", i);
    }
  }
}