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Subject: [OMPI users] Memory manager
From: Terry Frankcombe (terry_at_[hidden])
Date: 2008-05-12 23:12:57

Hi folks

I'm trying to run an MPI app on an infiniband cluster with OpenMPI

When run on a single node, this app is grabbing large chunks of memory
(total per process ~8.5GB, including strace showing a single 4GB grab)
but not using it. The resident memory use is ~40MB per process. When
this app is compiled in serial mode (with conditionals to remove the MPI
calls) the memory use is more like what you'd expect, 40MB res and
~100MB vmem.

Now I didn't write it so I'm not sure what extra stuff the MPI version
does, and we haven't tracked down the large memory grabs.

Could it be that this vmem is being grabbed by the OpenMPI memory
manager rather than directly by the app?


Dr. Terry Frankcombe
Research School of Chemistry, Australian National University
Ph: (+61) 0417 163 509    Skype: terry.frankcombe