FORTRAN pinned memory Using pinned memory from FORTRAN

I have been trying to achieve faster data transfer between the CPU and GPU by using pinned memory. I can run the FORTRAN thunking cuBLAS pinned memory example from but when I tried to implement it in my own program it fails. The program fails when I set the initial values one of the variables but even if I skip this the program will crash when I try to retrieve one of the variables from GPU memory. I am using the gnu compilers version 4.3.2 on 64bit Ubuntu 8.10. I have also tried the latest 4.4.1 gnu compilers and got the same error. This is the portion of the code that fails. I have also included the full code as an attachment, the fortran.c file is a symbolic link so you may need to change its location to get it to work.

Thanks in advance,


[codebox]program main

use iso_c_binding

implicit none

include ‘’

!define the floating point kind to be single precision

integer, parameter :: fp_kind = kind(1.d0)	!double = kind(1.d0) single = kind(1.0)

integer :: N

real(fp_kind), dimension(:,:), pointer :: II,CC,AA

real(fp_kind), dimension(:), pointer :: AV,BV

integer :: I_ptr,CC_ptr,AV_ptr,BV_ptr,AA_ptr

type(C_PTR) :: cptr_II,cptr_CC,cptr_AV,cptr_BV,cptr_AA

integer :: res

! Define matrices as pointer.

!real (fp_kind), dimension(:,:), pointer ::      A, B, C

real(fp_kind) :: alpha, beta

real :: tic,toc

real :: time_send, time_comp,time_retrieve

integer :: i,j

integer :: sizeof_real = 8

integer :: icuBLAS_error

integer :: cublas_alloc

integer :: cublas_set_matrix

integer :: cublas_get_matrix

integer :: cublas_set_vector

integer :: cublas_get_vector

real(fp_kind) :: cublas_Dasum

real(fp_kind) :: cublas_sasum

external cublas_alloc

external cublas_set_matrix

external cublas_get_matrix



external cublas_Dasum

external cublas_Sasum

write(*,*) "enter Matrix size"

read(*,"(i4)") N

! allocate(AA(N,N))

res = cudaMallocHost ( cptr_AA, n*n*sizeof(fp_kind) )

call c_f_pointer ( cptr_AA, AA, (/ n, n /) )

if(res /=0) STOP

! allocate(II(N,N))

res = cudaMallocHost ( cptr_II, n*n*sizeof(fp_kind) )

call c_f_pointer ( cptr_II, II, (/ n, n /) )

if(res /=0) STOP

! allocate(CC(N,N))

res = cudaMallocHost ( cptr_CC, n*n*sizeof(fp_kind) )

call c_f_pointer ( cptr_CC, CC, (/ n, n /) )

if(res /=0) STOP

! allocate(AV(N))

res = cudaMallocHost ( cptr_AV, n*sizeof(fp_kind) )

call c_f_pointer ( cptr_AV, AV, (/ n/) )

if(res /=0) STOP

! allocate(BV(N))

res = cudaMallocHost ( cptr_BV, n*sizeof(fp_kind) )

call c_f_pointer ( cptr_BV, BV, (/ n /) )

alpha = 1.0

beta = 0.0

sizeof_real = fp_kind

call cublas_init

write(*,*) 'Check 1'

do i = 1,N

    !write(*,*) i

    do j = 1,N

        II(i,j) = 0._fp_kind

        !write(*,*) i,j,i*j

        !AA(i,j) = 1._fp_kind  !This causes a seg fault

    end do

        AV(i) = real(i)

        II(i,i) = 1._fp_kind

end do


CC = 0._fp_kind

write(*,*) 'Check 1.5'

AA=1._fp_kind !This causes a seg fault

[/codebox] (6.05 KB)