Re: [OMPI devel] Bad performance (20% bandwidth loss) when compiling with GCC 5.2 instead of 4.x

2015-10-15 Thread Paul Kapinos
On 10/14/15 19:35, Jeff Squyres (jsquyres) wrote: On Oct 14, 2015, at 12:48 PM, Nathan Hjelm wrote: I think this is from a known issue. Try applying this and run again: https://github.com/open-mpi/ompi/commit/952d01db70eab4cbe11ff4557434acaa928685a4.patch The good news is

Re: [OMPI devel] Bad performance (20% bandwidth loss) when compiling with GCC 5.2 instead of 4.x

2015-10-14 Thread Jeff Squyres (jsquyres)
On Oct 14, 2015, at 12:48 PM, Nathan Hjelm wrote: > > I think this is from a known issue. Try applying this and run again: > > https://github.com/open-mpi/ompi/commit/952d01db70eab4cbe11ff4557434acaa928685a4.patch The good news is that if this fixes your problem, the fix is

Re: [OMPI devel] Bad performance (20% bandwidth loss) when compiling with GCC 5.2 instead of 4.x

2015-10-14 Thread Nathan Hjelm
I think this is from a known issue. Try applying this and run again: https://github.com/open-mpi/ompi/commit/952d01db70eab4cbe11ff4557434acaa928685a4.patch -Nathan On Wed, Oct 14, 2015 at 06:33:07PM +0200, Paul Kapinos wrote: > Dear Open MPI developer, > > We're puzzled by reproducible

[OMPI devel] Bad performance (20% bandwidth loss) when compiling with GCC 5.2 instead of 4.x

2015-10-14 Thread Paul Kapinos
Dear Open MPI developer, We're puzzled by reproducible performance (bandwidth) penalty observed when comparing measurements via InfibiBand between two nodes, OpenMPI/1.10.0 compiled with *GCC/5.2* instead of GCC 4.8 and Intel compiler. Take a look at the attached picture of two measurements