Thanks. I thought those threads will not interfere with each other since they have no common variables except std IO.
List-Post: users@lists.open-mpi.org Date: Thu, 3 Sep 2009 09:01:28 -0700 From: eugene....@sun.com To: us...@open-mpi.org Subject: Re: [OMPI users] Help! guosong wrote: I am new to open MPI I am not, but I'm not real familiar with thread-safe MPI programming. Still, I saw no other replies to your question, so I'll make an attempt to answer. MPI does not guarantee thread safety. E.g., see http://www.mpi-forum.org/docs/mpi-20-html/node162.htm#Node162 and the ensuing pages. To do what you want to do, you need to make sure you have thread safety. There is a standard MPI interface for doing so. I'm not good at C++, so here is a C example: #include <stdio.h> #include <mpi.h> int main(int argc, char **argv) { int provided; /* start MPI, asking for support for multiple threads */ MPI_Init_thread(&argc,&argv,MPI_THREAD_MULTIPLE,&provided); /* report what level of support is actually provided */ if ( MPI_THREAD_SINGLE == provided ) printf(" MPI_THREAD_SINGLE\n"); if ( MPI_THREAD_FUNNELED == provided ) printf(" MPI_THREAD_FUNNELED\n"); if ( MPI_THREAD_SERIALIZED == provided ) printf(" MPI_THREAD_SERIALIZED\n"); if ( MPI_THREAD_MULTIPLE == provided ) printf(" MPI_THREAD_MULTIPLE\n"); /* exit */ MPI_Finalize(); return 0; } Run this program. If the program does not print out "MPI_THREAD_MULTIPLE", you're not getting the level of thread support you require and your program is not guaranteed to run properly. You have to make sure you're using a thread-safe MPI before you can expect your program to work. The next question is whether Open MPI is thread safe, and I'll leave you with this: http://www.open-mpi.org/faq/?category=supported-systems#thread-support Good luck. Again, I'm not experienced with thread-safe MPI programming (though I understand the general concepts). _________________________________________________________________ MSN十周年庆典，查看MSN注册时间，赢取神秘大奖 http://10.msn.com.cn
