> On Mar 13, 2020, at 9:33 AM, Jeffrey Layton via users > <users@lists.open-mpi.org> wrote: > > Good morning, > > I've compiled a hello world MPI code and when I run it, I get some messages > I'm not familiar with. The first one is, > > -------------------------------------------------------------------------- > WARNING: Linux kernel CMA support was requested via the > btl_vader_single_copy_mechanism MCA variable, but CMA support is > not available due to restrictive ptrace settings. > > The vader shared memory BTL will fall back on another single-copy > mechanism if one is available. This may result in lower performance. > > Local host: laytonjb-desktop > --------------------------------------------------------------------------
This is just a warning message. It's basically telling you exactly what it says: Linux Cross Memory Attach (CMA) support was requested, but Open MPI couldn't enable it at run time. So it fell back to a different shared memory technology, instead. It's warning you of this because CMA is the fastest shared memory support, and it fell back to a slightly-slower shared memory technology. > Then the code runs fine but after the code stops I get the following: > > [laytonjb-desktop:09116] 3 more processes have sent help message > help-btl-vader.txt / cma-permission-denied > [laytonjb-desktop:09116] Set MCA parameter "orte_base_help_aggregate" to 0 to > see all help / error messages This is just Open MPI's de-duplication of help messages. I.e., all 4 processes reported the message, but Open MPI's mpirun a) only showed the message in full once, and b) showed you that 3 other processes reported the same message. > I'm just running this code on my desktop. > > The compiler is PGI 19.10 and I'm using their 3.1.3 build of Open MPI. Any chance you can upgrade to 4.0.latest? :-) -- Jeff Squyres jsquy...@cisco.com
