[Difx-users] MPI issue (with solution) [SEC=OFFICIAL] {External}

[Phillips, Chris (S&A, Marsfield)]

OFFICIAL

Hi all,

Recently I had a strange problem running DIFX . It ran OK but I got a lot of output along the lines of:


[HOSTNAME:PID] Read -1, expected 530112, errno = 1

This turned out to be a conflict between the default Debian security settings and MPI trying to figure out optimal setup.

Without understanding the security implications, I disabled via  setting


btl_vader_single_copy_mechanism = none

In ~/.openmpi/mca-params.conf.

Apparently you can enable this using:


echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope

Cheers
Chris



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