Hello Miguel, On Friday 25 August 2006 15:40, Miguel Figueiredo Mascarenhas Sousa Filipe wrote: > Hi, > > On 8/25/06, Sven Stork <st...@hlrs.de> wrote: > > > > Hello Miguel, > > > > this is caused by the shared memory mempool. Per default this shared > > memory > > mapping has a size of 512 MB. You can use the "mpool_sm_size" parameter to > > reduce size e.g. > > > > mpirun -mca mpool_sm_size <SIZE> ... > > > > using > mpirun -mca mpool_sm_size 0 > is acceptable ? > to what will it fallback ? sockets? pipes? tcp? smoke signals?
0 will not work. But if you don't need shared memory communication you can disable the sm btl like: mpirun -mca btl ^sm .... Thanks, Sven > thankyou very much by the fast answer. > > Thanks, > > Sven > > > > On Friday 25 August 2006 15:04, Miguel Figueiredo Mascarenhas Sousa Filipe > > wrote: > > > Hi there, > > > I'm using openmpi-1.1 on a linux-amd64 machine and also a linux-32bit > > x86 > > > chroot environment on that same machine. > > > (distro is gentoo, compilers: gcc-4.1.1 and gcc-3.4.6) > > > > > > In both cases openmpi-1.1 shows a +/-400MB overhead in virtual memory > > usage > > > (virtual address space usage) for each MPI process. > > > > > > In my case this is quite troublesome because my application in 32bit > > mode is > > > counting on using the whole 4GB address space for the problem set size > > and > > > associated data. > > > This means that I have a reduction in the size of the problems which it > > can > > > solve. > > > (my aplication isn't 64bit safe yet, so I need to run in 32bit mode, and > > use > > > effectively the 4GB address space) > > > > > > > > > Is there a way to tweak this overhead, by configuring openmpi to use > > smaller > > > buffers, or anything else ? > > > > > > I do not see this with mpich2. > > > > > > Best regards, > > > > > > -- > > > Miguel Sousa Filipe > > > > > _______________________________________________ > > users mailing list > > us...@open-mpi.org > > http://www.open-mpi.org/mailman/listinfo.cgi/users > > > > > > -- > Miguel Sousa Filipe >
