Initialize MPI on mdserver

[benjaminjeliot]

Hi everyone,

Is it possible to intialize MPI in the mdserver, or the metadata component of a plugin?

I am hitting a runtime error in my custom plugin in the metadata component due to MPI not initialized.

Thanks,
Jim

[biagas]

Portions of Database plugins are shared between mdserver and engine. The mdserver isn't parallelized, only the engine. If you need MPI in the plugin, you must wrap the parallel code in #ifdef PARALLEL. There are also methods in avtParallel (src/avt/Pipeline/Pipeline) that wrap MPI calls and handle the check for whether or not PARALLEL is defined.

[benjaminjeliot]

Hi @biagas, thanks for your reply.

I have been trying to use an MPI-enabled library in my a plugin, but it fails when trying to read the metadata because MPI is not yet intialized.

I was hoping that there might be a way to work around it. I wondered if it would be possible to achieve 1-rank MPI in the mdserver component of the plugin.

Thanks,
Jim

[biagas]

We have other third party I/O libraries that are MPI-enabled. We end up also building a serial version and use the serial version for the mdserver.

[benjaminjeliot]

Hi @biagas ,
Thanks, maybe I can use the same approach for my library.

[biagas]

ADIOS2 plugin is one that takes this approach. You might want to take a look at config-site/quartz386.cmake to see how the libraries get specified in the host-config-site file. And databases/ADIOS2/ADIOS2.xml for how the parallel/serial libs are listed for generating the CMakeLists.txt