[OMPI users] Scalability issue

2010-12-02 Thread Benjamin Toueg
Hi, I am using DRAGON, a neutronic simulation code in FORTRAN77 that has its own datastructures. I added a module to send these data structures thanks to MPI_SEND / MPI_RECEIVE, and everything worked perfectly for a while. Then I had to raise the number of data structures to be sent up to a point

Re: [OMPI users] Scalability issue

2010-12-02 Thread Jeff Squyres
Do you get a corefile? It looks like you're calling MPI_RECV in Fortran and then it segv's. This is *likely* because you're either passing a bad parameter or your buffer isn't big enough. Can you double check all your parameters? Unfortunately, there's no line numbers printed in the stack tra

Re: [OMPI users] Scalability issue

2010-12-02 Thread Gus Correa
Hi All I wonder if configuring OpenMPI while forcing the default types to non-default values (-fdefault-integer-8 -fdefault-real-8) might have something to do with the segmentation fault. Would this be effective, i.e., actually make the the sizes of MPI_INTEGER/MPI_INT and MPI_REAL/MPI_FLOAT bigg

Re: [OMPI users] Scalability issue

2010-12-02 Thread Martin Siegert
Hi All, just to expand on this guess ... On Thu, Dec 02, 2010 at 05:40:53PM -0500, Gus Correa wrote: > Hi All > > I wonder if configuring OpenMPI while > forcing the default types to non-default values > (-fdefault-integer-8 -fdefault-real-8) might have > something to do with the segmentation fa

Re: [OMPI users] Scalability issue

2010-12-05 Thread Benjamin Toueg
Hi, First of all thanks for your insight ! *Do you get a corefile?* I don't get a core file, but I get a file called _FIL001. It doesn't contain any debugging symbols. It's most likely a digested version of the input file given to the executable : ./myexec < inputfile. *there's no line numbers p

Re: [OMPI users] Scalability issue

2010-12-05 Thread Gustavo Correa
Hi Benjamin I would just rebuild OpenMPI withOUT the compiler flags that change the standard sizes of "int" and "float" (do a "make cleandist" first!), then recompile your program, and see how it goes. I don't think you are gaining anything by trying to change the standard "int/integer" and "re

Re: [OMPI users] Scalability issue

2010-12-05 Thread Tim Prince
On 12/5/2010 3:22 PM, Gustavo Correa wrote: I would just rebuild OpenMPI withOUT the compiler flags that change the standard sizes of "int" and "float" (do a "make cleandist" first!), then recompile your program, and see how it goes. I don't think you are gaining anything by trying to change th

Re: [OMPI users] Scalability issue

2010-12-05 Thread Benjamin Toueg
Unfortunately DRAGON is old FORTRAN77. Integers have been used instead of pointers. If I compile it in 64bits without -f-default-integer-8, the so-called pointers will remain in 32bits. Problems could also arise from its data structure handlers. Therefore -f-default-integer-8 is absolutely necessa

Re: [OMPI users] Scalability issue

2010-12-06 Thread Gustavo Correa
Hi Benjamin I guess you could compile OpenMPI with standard integer and real sizes. Then compile your application (DRAGON) with the flags to change to 8-byte integers and 8-byte reals. We have some programs here that use real8 and are compiled this way, and run without a problem. I guess this is w

Re: [OMPI users] Scalability issue

2010-12-07 Thread Jeff Squyres
It is always a good idea to have your application's sizeof(INTEGER) match the MPI's sizeof(INTEGER). Having them mismatch is a recipe for trouble. Meaning: if you're compiling your app with -make-integer-be-8-bytes, then you should configure/build Open MPI with that same flag. I'm thinking tha

Re: [OMPI users] Scalability issue

2010-12-07 Thread Gus Correa
Hi Jeff Did I understand you right? Are you saying that one can effectively double the counting capability (i.e. the "count" parameters in MPI calls) of OpenMPI by compiling it with 8-byte integer flags? And long as one consistently uses the same flags to compile the application, everything wou

Re: [OMPI users] Scalability issue

2010-12-07 Thread Jeff Squyres
On Dec 7, 2010, at 8:33 AM, Gus Correa wrote: > Did I understand you right? > > Are you saying that one can effectively double the counting > capability (i.e. the "count" parameters in MPI calls) of OpenMPI > by compiling it with 8-byte integer flags? Yes and no. If you increase the size of INT

Re: [OMPI users] Scalability issue

2010-12-24 Thread Benjamin Toueg
Hi, I did some testing and felt like giving some feeback. When I started this discussion I compiled openmpi like that: ./configure --prefix=/home/toueg/openmpi CXX=g++ CC=gcc F77=gfortran FC=gfortran *FLAGS="-m64 -fdefault-integer-8 -fdefault-real-8 -fdefault-double-8" FCFLAGS="-m64 -fdefault-inte