MTT offers a high degree of flexibility by allowing phases to be effectively parameterized allowing for multiple executions of each phase.
Caution needs to be executed when creating an INI file that will not take days (or weeks!) to complete. For the perl MTT client, one can use the
--print-time option to see how long each phase is taking to help tune your INI file.
We recommend running with
--verbose. This provides a decent amount of output that confirms that most MTT things are running. However, if you run into weird issues that cannot be explained, run with
--debug. This will provide a lot of output (you’ll want to save both stdout and stderr into a file for later analysis).
Some compilers (such as the Intel compilers) require additional environment variables such as PATH and LD_LIBRARY_PATH to be set properly in order to find their relevant parts. It is easiest to simply set these values before invoking the MTT client, but with the perl MTT client, it is also possible to set them within the INI file directly (so that you don’t have to worry about local environments). However, the syntax is a little odd, so it’s worth describing here:
[MPI Install: Intel compiler] ...all the other fields... setenv = PATH /path/to/intel/compiler/bin:/usr/bin/:...rest of path setenv = LD_LIBRARY_PATH /path/to/intel/compiler/lib:...rest of LD path
Sometimes MTT finds a problem in a middleware install, but a human wants to go examine it manually. When MTT installs a middleware under its scratch tree, it will automatically drop two files – one for sh-flavored shells and one for csh-flavored shells – that set the PATH and LD_LIBRARY_PATH to get to the middleware install. The exact location of these files depends on the section names in your INI file and the exact version number of the MPI in question. Specifically, these files will be in:
<patch to your scratch>/installs/<MPI Get name>/<MPI Install name>/<MPI version number>/mpi_installed_vars.sh <patch to your scratch>/installs/<MPI Get name>/<MPI Install name>/<MPI version number>/mpi_installed_vars.csh
Hence, you can source these files like this (assuming a csh-flavored shell):
shell% cd <patch to your scratch>/installs/<MPI Get name>/<MPI Install name>/<MPI version number> shell% source mpi_installed_vars.csh
Mpicc, mpirun, etc. will then be in your PATH, and the appropriate libraries will be in your LD_LIBRARY_PATH. Additionally, the environment variable MPI_ROOT will be set that points to the top-level installation directory for the middlewareBuild. This is useful with Open MPI’s
--prefix option to mpirun, for example. Note that all the files related to the testing of that MPI are under this tree – the source tree, the tests, etc. So you can go examine the entire test – not just put the MPI in question in your path.
Note this debugging mechanism is currently only available with the Perl MTT client.