GCC 10 released today

3

I have compiled the following code, inspired by the first example in https://docs.computecanada.ca/wiki/OpenACC_Tutorial_-_Adding_directives

program example_acc

implicit none
integer :: i, N
real(8), dimension(1:200000000) :: x
real(8), dimension(1:200000000) :: y
real(8) :: a

a = 3.14159265d0
N = 200000000

!$acc kernels
do i = 1, N
    x(i) = 1.0d0
    y(i) = 2.0d0
end do

y(:) = a*x(:) + y(:)
!$acc end kernels

end program example_acc

I am using gfortran 9.3.0 under Ubuntu 20.04:

$ gfortran example_acc.f90 && time ./a.out

real    0m2,237s
user    0m1,477s
sys     0m0,760s

When trying to compile with -fopenacc, I had the following error:

lto-wrapper: fatal error: could not find accel/nvptx-none/mkoffload in /usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/ (consider using ‘-B’)

compilation terminated.
/usr/bin/ld : erreur : lto-wrapper failed
collect2: error: ld returned 1 exit status

I have installed the gcc-offload-nvptx packages: “This package contains libgomp plugin for offloading to NVidia PTX. The plugin needs libcuda.so.1 shared library that has to be installed separately.”

$ gfortran -fopenacc example_acc.f90 && time ./a.out

real    0m2,557s
user    0m1,667s
sys     0m0,891s

So, it seems you need a NVidia accelerator, but I have an ATI Radeon on my HP ZBook…

1 Like