On Tuesday 23 August 2005 14.52, Jeff Squyres wrote: > ... > > Now I'd like to control over which channels/transports/networks the > > data > > flows... I configured and built ompi against mvapi (mellanox > > ibgd-1.8.0) and > > as far as I can tell it went well. Judging by the behaviour of the > > tests I > > have done it defaults to tcp (over ethernet in my case). How do I > > select > > mvapi? > > The Open MPI guys working on IB (from Los Alamos) are at the IB > workshop this week, and their responses may be a bit slow. They're the > ones who can give the definitive answers, but I'll take a shot...
That's ok, I was both interested in the general way to handle transport selection and specifically how to fix this one. > > I'm a little surprised that tcp was used -- OMPI should "prefer" the > low latency interconnects (such as mvapi) to tcp and automatically use > them. One main thing I'd like is a "working" --verbose (adding it to mpirun doesn't give me a single extra line of output) that would tell me something like: ..looking for transports, found: self, mvapi, tcp. ..testing trasnports: self ok, mvapi fail, tcp ok. ..assembeling final list of transports: self, tcp. ... > > I see from your ompi_info output that the 2 mvapi components were built > and installed properly, so that's good. > > ... > mpirun --mca btl_base_include self,mvapi -np 4 a.out > > This will tell OMPI that you want to use the "self" (i.e., loopback) > and "mvapi" BTLs, and no others. > > Try this and see if you get better results. Nope, no errors, no extra output, but same ethernet-tcp-like performance (32 us and 116 MiB/s). /Peter -- ------------------------------------------------------------ Peter Kjellström | National Supercomputer Centre | Sweden | http://www.nsc.liu.se
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