Developer Guide

  • 2021.2
  • 03/31/2021
  • Public Content
Contents

Problem: MPI limitation for Docker*

Problem
The command fails with the following message:
[root@n1 /]# I_MPI_DEBUG=12 mpirun -n 2 -ppn 1 -env I_MPI_PIN_DOMAIN socket IMB-MPI1 bcast impi_shm_heap_init(): mbind failed (p=0x7f3078b0e000, size=536870912) impi_shm_heap_init(): mbind failed (p=0x7f9b808bc000, size=536870912)
Cause
MPI has a limitation on the
dev/shm
area. It should be not less than 4GB for a node with 2 sockets. By default, the Docker* container set 64MB, which is not enough.
Solution
  1. Make sure the problem is the small size of
    shm
    area:
    $df -h /dev/shm root@n1 /]# df -h /dev/shm Filesystem      Size Used Avail Use% Mounted on shm             4.0G   0 4.0G   0% /dev/shm
  2. If it is true, restart Docker using the following command:
    --shm-size=4gbdocker run --shm-size=4gb …

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.