可分配的 fortran openacc 派生类型

Question

我读到 Fortran 派生类型的手动深度复制是可能的，但是下面的简单测试程序在运行时失败了；程序使用 PGI v16.10 编译干净。哪里出错了？

program Test

    implicit none

    type dt
        integer :: n
        real, dimension(:), allocatable :: xm
    end type dt

    type(dt) :: grid
    integer :: i

    grid%n = 10
    allocate(grid%xm(grid%n))

!$acc enter data copyin(grid)
!$acc enter data pcreate(grid%xm)

!$acc kernels
   do i = 1, grid%n
      grid%xm(i) = i * i
   enddo
!$acc end kernels

   print*,grid%xm

end program Test

我得到的错误是：

call to cuStreamSynchronize returned error 700: Illegal address during kernel execution
call to cuMemFreeHost returned error 700: Illegal address during kernel execution

Answer 1

您只需在 kernels 指令中添加一个 "present(grid)" 子句。

这是您的程序示例，其中包含修复程序以及一些其他内容，例如更新数据以便可以在主机上打印。

% cat test.f90
program Test

    implicit none

    type dt
        integer :: n
        real, dimension(:), allocatable :: xm
    end type dt

    type(dt) :: grid
    integer :: i

    grid%n = 10
    allocate(grid%xm(grid%n))

!$acc enter data copyin(grid)
!$acc enter data create(grid%xm)
!$acc kernels present(grid)
   do i = 1, grid%n
      grid%xm(i) = i * i
   enddo
!$acc end kernels
!$acc update host(grid%xm)
   print*,grid%xm

!$acc exit data delete(grid%xm, grid)
   deallocate(grid%xm)

end program Test

% pgf90 -acc test.f90 -Minfo=accel -ta=tesla -V16.10; a.out
test:
     16, Generating enter data copyin(grid)
     17, Generating enter data create(grid%xm(:))
     18, Generating present(grid)
     19, Loop is parallelizable
         Accelerator kernel generated
         Generating Tesla code
         19, !$acc loop gang, vector(128) ! blockidx%x threadidx%x
     23, Generating update self(grid%xm(:))
    1.000000        4.000000        9.000000        16.00000
    25.00000        36.00000        49.00000        64.00000
    81.00000        100.0000

请注意，PGI 17.7 将包括 Beta 支持 Fortran 中的真正深层复制。与上面的手动深拷贝相反。下面是一个使用真正深拷贝的例子：

% cat test_deep.f90
program Test

    implicit none

    type dt
        integer :: n
        real, dimension(:), allocatable :: xm
    end type dt

    type(dt) :: grid
    integer :: i

    grid%n = 10
    allocate(grid%xm(grid%n))

!$acc enter data copyin(grid)
!$acc kernels present(grid)
   do i = 1, grid%n
      grid%xm(i) = i * i
   enddo
!$acc end kernels
!$acc update host(grid)
   print*,grid%xm

!$acc exit data delete(grid)
   deallocate(grid%xm)

end program Test

% pgf90 -acc test_deep.f90 -Minfo=accel -ta=tesla:deepcopy -V17.7 ; a.out
test:
     16, Generating enter data copyin(grid)
     17, Generating present(grid)
     18, Loop is parallelizable
         Accelerator kernel generated
         Generating Tesla code
         18, !$acc loop gang, vector(128) ! blockidx%x threadidx%x
     22, Generating update self(grid)
    1.000000        4.000000        9.000000        16.00000
    25.00000        36.00000        49.00000        64.00000
    81.00000        100.0000

可分配的 fortran openacc 派生类型

fortran openacc derived types with allocatable

fortran

gpu

pgi

openacc