CODEWITHSUNDEEP
fortranmpiintel-fortranintel-mpi
Jakob Filser
Jakob Filser

Reputation: 130

MPI allocating massive amounts of memory on startup

I am trying to run an MPI application compiled with mpiifort (ifort (IFORT) 2021.6.0 20220226) using mpiexec.hydra (Intel(R) MPI Library for Linux* OS, Version 2021.6 Build 20220227 (id: 28877f3f32)), on a machine with 36 Intel(R) Xeon(R) Platinum 8360Y CPU @ 2.40GHz cores.

Before any actual work is done, that is before the actual application prints any output, massive amounts of memory are allocated (tens to hundreds of GB). This seems to depend on the number of cores used. With more than 30 cores, MPI actually crashes because it runs out of memory.

Is this an MPI or compiler bug? What is all this memory allocated for? Can I control its amount somehow?

Edit: here's a minimal example

program test
  implicit none 
  integer :: mpi_err

  include "mpif.h"

  call MPI_INIT(mpi_err)
  call MPI_FINALIZE()

end program

Upvotes: 0

Views: 183

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