[mpich-discuss] Hangup or stall at MPI_INIT

[Rajeev Thakur]

I have thought the problem may have to do with stdin/stdout. Can you comment out any prints in the program and try.

Rajeev

On Dec 7, 2012, at 11:40 AM, Ryan Crocker wrote:

> I haven't tried that specific example but i don't see the hang when i the use intel compiler sets. I wrote a quick "hello world" and that runs every time, compiled with gfortran.  I was thinking it was something to do with running past the node memory but when i check to see how much each core is allocating that's not possible from my code.  The other thing i thought to try to day was remove a lot of interface calls from the parallel module and make a stand alone parallel_init module that is the very first thing called, i don't know why that would work but i'm trying it anyway.  
> 
> On Dec 7, 2012, at 8:51 AM, Rajeev Thakur wrote:
> 
>> Does the pi3f90 example in the examples/f90 directory work? I have had that hang with gfortran for unknown reasons.
>> 
>> Rajeev
>> 
>> On Dec 6, 2012, at 11:27 PM, Ryan Crocker wrote:
>> 
>>> Hi all, 
>>> 
>>> I'm having a problem with hangups or some sort of stall.  Basically the program will keep running, or look as it if is on the cluster i'm running on (i've noticed this issue on multiple clusters actually), But nothing is happening.  When i have every processor print out they all do right before MPI_INIT and not after.  I counted the files and all the processors are entering the call.  What makes it even more odd is that the same exact simulation will run if i decrease the number of nodes/cores i'm using, i.e. i'll run on 96 cores (or more) and moving to 72 my program will run without issue.   
>>> 
>>> I'm using the latest gcc compiler set with the latest version of MPICH2 configured with:
>>> 
>>> '--with-pbs=/PBS' '--with-default-comm=pmi' '--enable-pbspro-helper' 'CC=gcc' 'LDFLAGS=-lpthread' 'CPPFLAGS=-fpic'
>>> 
>>> I've changed to the intel/mpich2 compiler set and have not had the same problem.  I have no idea what this issue could be and have had little luck finding an answer with stackoverflow or google searches any help would be much appreciated.  Also, hit me up for any more information you'd need to help.
>>> 
>>> Thanks,
>>> 
>>> My flow solver is written in fortran and here are the subroutines leading up to the MPI_INIT call, and the whole flow solver is compiled with '-O3 -ffree-line-length-none' :
>>> 
>>> ! ====================================== !
>>> program main
>>> 
>>> call main_init
>>> call simulation_run
>>> call main_stop
>>> 
>>> end program main
>>> 
>>> ! ====================================== !
>>> 
>>> subroutine main_init
>>> use string
>>> implicit none
>>> character(len=str_medium) :: input_name
>>> 
>>> call parallel_init
>>> 
>>> ! Initialize the random number generator
>>> call random_init
>>> 
>>> ! Parse the input file
>>> call parser_init
>>> 
>>> input_name='input' 
>>> call parser_parsefile(input_name)
>>> 
>>> ! Geometry initialization
>>> call geometry_init
>>> 
>>> ! Data initialization
>>> call data_init
>>> 
>>> ! Simulation initialization
>>> call simulation_init
>>> 
>>> return
>>> end subroutine main_init
>>> 
>>> ! ====================================== !
>>> 
>>> subroutine parallel_init
>>> use parallel
>>> use parser
>>> implicit none
>>> integer :: ierr
>>> integer :: size_real,size_dp
>>> 
>>> ! Initialize a first basic MPI environment
>>> 
>>> !##### This is where it stall out #########
>>> 
>>> call MPI_INIT(ierr)
>>> call MPI_COMM_RANK(MPI_COMM_WORLD,irank,ierr)
>>> call MPI_COMM_SIZE(MPI_COMM_WORLD,nproc,ierr) 
>>> irank = irank+1
>>> iroot = 1
>>> 
>>> ! Set MPI working precision - WP
>>> call MPI_TYPE_SIZE(MPI_REAL,size_real,ierr)
>>> call MPI_TYPE_SIZE(MPI_DOUBLE_PRECISION,size_dp,ierr)
>>> if (WP .eq. size_real) then
>>>   MPI_REAL_WP = MPI_REAL
>>> else if (WP .eq. size_dp) then
>>>   MPI_REAL_WP = MPI_DOUBLE_PRECISION
>>> else
>>>   call parallel_kill('Error in parallel_init: no WP equivalent in MPI')
>>> end if
>>> 
>>> ! Set MPI single precision
>>> call MPI_TYPE_SIZE(MPI_REAL,size_real,ierr)
>>> call MPI_TYPE_SIZE(MPI_DOUBLE_PRECISION,size_dp,ierr)
>>> if (SP .eq. size_real) then
>>>   MPI_REAL_SP = MPI_REAL
>>> else if (SP .eq. size_dp) then
>>>   MPI_REAL_SP = MPI_DOUBLE_PRECISION
>>> else
>>>   call parallel_kill('Error in parallel_init: no SP equivalent in MPI')
>>> end if
>>> 
>>> ! For now, comm should point to MPI_COMM_WORLD
>>> comm = MPI_COMM_WORLD
>>> 
>>> return
>>> end subroutine parallel_init
>>> 
>>> ! ============================= !
>>> 
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>> 
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> 
> Ryan Crocker
> University of Vermont, School of Engineering
> Mechanical Engineering Department
> rcrocker at uvm.edu
> 315-212-7331
> 
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