On Fri, 15 Aug 2008, Kozin, I \(Igor\) wrote:
> Hello, I would really appreciate any advice on troubleshooting/tuning > Open MPI over ConnectX. More details about our setup can be found here > http://www.cse.scitech.ac.uk/disco/database/search-machine.php?MID=52 > Single process per node (ppn=1) seems to be fine (the results for IMB > can be found here This behaviour happens on all Mellanox devices. I have been in contact with them to in get more information about it, but never got a convincing answer. According to Mellanox it happened because my Infinihost III Lx was not designed for a system with 8 cores in total, it should not happen with Infinihost III Ex or ConnectX. As you noticed, it also happens with ConnectX, and I can confirm it also happens on systems with only 4 cores total. However, the problem is less severe with ConnectX than with Infinihost III. The solution for me has been to sell QLogic rather than Mellanox to customers who need good AllToAll. Daniël
