HP-MPI Version 2.0 for Windows Release Note

13 Known Issues and Workarounds
This chapter describes known issues and workarounds for this release.
13.1 Calling Conventions
The Fortran interface provided in HP-MPI assumes a style calling convention of C-by- reference.
That is, function names are not decorated as _function@bytes, arguments are passed by reference,
string length arguments are passed by value after the other arguments, and the caller cleans the
stack. This is not compatible with Compaq Visual Fortran (CVF) or other compilers using the
STDCALL calling convention for Fortran routines (for example, /iface:cvf in Intel Fortran).
The STDCALL calling convention decorates the function names, passes string lengths by value
directly after the string, and has the callee clean the stack.
13.2 Flushing Buffered IO
Certain cases do not flush rank IO properly. HP-MPI flushes existing IO at various points,
including MPI_Finalize. When you link the rank/application using Dynamic Runtime Libraries
(/MD or /MDd), the flushes issued by the HP-MPI libraries also flush rank IO. The mpicc scripts
now link using /MD by default.
Certain situations still exist where rank IO might not be properly flushed. These generally occur
when ranks exit unexpectedly. The only way to guarantee IO flushes is for ranks to issue flush
commands when necessary, and at program exit if not linking with /MD.
13.3 Jobs Not Running
When submitting multiple mpirun jobs to the HPC scheduler, the jobs all start but do not run.
The reason is a single mpirun task schedules additional HPMPIHPCService tasks. If there are
no job resources available for these tasks, the jobs sit in a queued state. If other mpirun jobs start
using the remaining tasks, they might block the previous mpirun.
The solution is to create a dependency between the mpirun tasks, so the later mpirun task does
not start until the previous mpirun task is completely finished.
13.4 Warning for No Cached Password
A "no cached password" warning might be issued when running local node jobs. If other
ranks are spawned later on other nodes, the warning is still valid. To prevent the warning, use
-cache to cache a password, or use -nopass to suppress the warning.
13.5 mpiexec Issue
The mpiexec.bat script supports the mpiexec command using the MS-MPI flags, if there is
an equivalent mpirun option. This script will translate the mpiexec flags to the equivalent
mpirun command if there is a comparable option.
13.6 MPI_COPY_LIBHPC
Depending upon your cluster setup, administrators might want to change the value of
MPI_COPY_LIBHPC to 0 in the hpmpi.conf file.
You should consider setting MPI_COPY_LIBHPC to 0 in the hpmpi.conf file to improve HP-MPI
job startup times if:
• Your HPC cluster is setup with .NET 3.5 Service Pack 1.
• Your .NET security permissions are modified so that user processes are allowed to
dynamically load .NET managed libraries over a network share.
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