Potential Challenge with ifort and OpenMP

David_Race · ‎03-26-2012

I have the following code that is compiled with ifort

================Begin Program=========================================

program mpiopenmp

use IFPORT

implicit none

integer :: i,j,k,ii,jj,sorl

character*1 :: argstr = 'S'

double precision:: stime, endtime

integer :: n_of_comm_args

integer :: ip

real(8) :: wet, inj

!

! cell variable

!

integer :: ierr

integer :: lx, ly, lz

integer :: local_lx, local_ly

integer :: local_ivoid

integer,allocatable,dimension(:,:,:),save :: cell

lx= 404

ly=404

lz=400

local_lx=lx

local_ly=ly

allocate( cell(-1:local_lx,-1:local_ly,0:lz-1) )

if (ip==0) then

print *, 'model size = ',lx,'*',ly,'*',lz

endif

wet = (1.0d0-sqrt(3.0d0)/2.0d0)/2.0d0

inj = 0.0d0

call srand(0)

do k=0,lz-1

do j=0,local_ly-1

do i=0,local_lx-1

if (rand() < .5) then

cell(i,j,k)=0

else

cell(i,j,k)=1

end if

end do

local_ivoid = 0

!$omp parallel

!$omp do reduction(+:local_ivoid) private(i,j,k) &

!$omp firstprivate(local_lx,local_ly)

do k=0,lz-1

do j=0,local_ly-1

do i=0,local_lx-1

if (cell(i,j,k)==0) local_ivoid = local_ivoid + 1

end do

!$omp end do

print *,local_ivoid

!$omp end parallel

!

end program mpiopenmp

======================End Program==================================

======================Makefile Start==================================

############################################################

# Setting

FC = ifort

FFLAGS = -O3 -openmp -xHost

LD = $(FC)

LDFLAGS = $(FFLAGS)

TARGET = MPI-OPENMP

MAIN_SRCS = MPI-OPENMP2.F90

OBJS = $(MAIN_SRCS:.F90=.o)

############################################################

# Rules

$(TARGET): $(OBJS)

$(LD) -o $@ $(OBJS) $(LDFLAGS)

MPI-OPENMP2.o: MPI-OPENMP2.F90

$(FC) $(FFLAGS) -c MPI-OPENMP2.F90

clean:

$(RM) -f *.[os] *.mod $(TARGET) *.o

############################################################

# SUFFIXS

.SUFFIXES:

.SUFFIXES: .o .F .f .F90 .f90 .c .s

############################################################

=======================Makefile End=============================

If I compile with gfortran or with ifort v 12.0.5 (dated 19 July 2011) or with ifort v 12.1.0 without -openmp , the result follows:

model size = 404 * 404 * 400

32635952

---------------------------------------------------------------------------------------------------

compiling with ifort v12.1.0 with -openmp yields

model size = 404 * 404 * 400

0

--------------------------------------------------------------------------------------------

This is part of a larger application, so this OpenMP construct is used several times in the application. Any help with this would be appreciated.

Thanks

David Race

program mpiopenmp use IFPORT implicit none integer :: i,j,k,ii,jj,sorl character*1 :: argstr = 'S' double precision:: stime, endtime integer :: n_of_comm_args integer :: ip real(8) :: wet, inj!! cell variable! integer :: ierr integer :: lx, ly, lz integer :: local_lx, local_ly integer :: local_ivoid integer,allocatable,dimension(:,:,:),save :: cell lx= 404 ly=404 lz=400 local_lx=lx local_ly=ly allocate( cell(-1:local_lx,-1:local_ly,0:lz-1) ) if (ip==0) then print *, 'model size = ',lx,'*',ly,'*',lz endif wet = (1.0d0-sqrt(3.0d0)/2.0d0)/2.0d0 inj = 0.0d0 call srand(0) do k=0,lz-1 do j=0,local_ly-1 do i=0,local_lx-1 if (rand() < .5) then cell(i,j,k)=0 else cell(i,j,k)=1 end if end do end do end do local_ivoid = 0!$omp parallel!$omp do reduction(+:local_ivoid) private(i,j,k) &!$omp firstprivate(local_lx,local_ly) do k=0,lz-1 do j=0,local_ly-1 do i=0,local_lx-1 if (cell(i,j,k)==0) local_ivoid = local_ivoid + 1 end do end do end do!$omp end doprint *,local_ivoid!$omp end parallel!end program mpiopenmp

TimP · ‎03-27-2012

I don't see such a problem with the current Intel64 version: 12.1.3.293 Build 20120212

David_Race · ‎03-27-2012

Thanks. I will get the admin to upgrade to the latest version.