Fortran OpenACC Runtime Library Routines

Accelerated Computing HPC Compilers Legacy PGI Compilers
#1

Hello,

Can you kindly identify what is wrong in the following code?

!      set ACC_DEVICE_TYPE=nvidia
!  use pgfortran -fast -o ACCHECK.exe  ACCHECK.for -ta=tesla:cc35

      Program ACCHECK
      use Openacc
      IMPLICIT NONE
      INTEGER :: ngpus
      integer, value :: devicenum
      integer(acc_device_kind), value :: devicetype
      integer(acc_device_property):: property
      character*(1000) :: string
      ngpus = acc_get_num_devices(devicetype)
      Write(*,*) 'Number of ACC devices are: ', ngpus
      property=acc_property_driver
      call acc_get_property_string(devicenum,devicetype,property,string)
      Write(*,*) string
      End Program

I have two NVIDIA GPUs: TITAN X and TESLA K40. I believe that the they are compute capability cc50 and cc35 respectively. When I execute the above code, I get 1 GPU and the “string” variable is empty.
Is there something wrong with my coding?
I am actually trying to check that the TESLA K40 is the one running my code. Any tips?

Thank you for your time.
Ahmed

#2

Hi Ahmed,

You need to set the device type and device number which you which to query. For example:

% cat test.f90
!      set ACC_DEVICE_TYPE=nvidia
!  use pgfortran -fast -o ACCHECK.exe  ACCHECK.for -ta=tesla:cc35

      Program ACCHECK
      use Openacc
      IMPLICIT NONE
      INTEGER :: ngpus
      integer, value :: devicenum
      integer(acc_device_kind), value :: devicetype
      integer(acc_device_property):: property
      character*(1000) :: string
      devicetype = acc_get_device_type()
      ngpus = acc_get_num_devices(devicetype)
      Write(*,*) 'Number of ACC devices are: ', ngpus
      do devicenum=1,ngpus
         property=acc_property_driver
         call acc_get_property_string(devicenum,devicetype,property,string)
         Write(*,*) trim(string)
      enddo
      End Program
% pgf90 -ta=tesla:cc70 test.f90; a.out
 Number of ACC devices are:             4
 9010
 9010
 9010
 9010

Hope this helps,
Mat