MPI调用需要多少堆栈空间？

Question

I am writing a code that combines the use of the Message Passing Interface (MPI) and qthreads. I am having to use a larger than default stack size (8KB as opposed to 4KB) even though my actual code uses well under 1 KB per qthread. I believe that the MPI calls are the cause of the stack overflow.

The code uses OpenMPI and qthreads from Sandia National Laboratories.

The code runs with a single qthread "shepherd" on each MPI process, using qthread_init(1) - qthreads is used only for context switching within an MPI process.

My questions are: 1) Is there a way to determine how much stack space an MPI call will use? 2) Is there a way to reduce how much stack space it uses? 3) Are there particular MPI calls that use a larger amount of stack space than average MPI calls?

Answer 1

There are profiling tools for this, google mpi profiling I would recommend mpip since its easy to setup. Also Valgrind has a section on debugging mpi and parallel programs. If these don't identity the problem you will have to dig deeper into performance tuning and play around with message sizes and such.

Answer 2

MPI can be called from Pthreads, which have something like an 8 MB default stack size. In practice, I think it's under 1 KB, with large temps allocated on the heap.