On Wed, 2017-04-19 at 13:58 +0200, pramod kumbhar wrote:

Hi Rob,

Is this already installed/avaialble on MIRA? I would like to try this to check some mpi i/o hints.

Yes, there are several versions available: manual progress optimized: /projects/aurora_app/mpich3-ch4-ofi/install/gnu/bin   auto progress optimized: /projects/aurora_app/mpich3-ch4-ofi/install-auto/gnu/bin   manual progress debug: /projects/aurora_app/mpich3-ch4-ofi/install/gnu.debug/bin   auto progress debug: /projects/aurora_app/mpich3-ch4-ofi/install-auto/gnu.debug/bin There are some performance considerations (both positive and negative) to consider: Current performance improvements versus [IBM's vendor-supplied MPICH]: 1.) Pt2pt latency - better than 2x speedup for small messages, large ones with few ranks-per-node less so due to detriment #2  listed below. 2.) RMA latency - exponentially better for small messages, then becomes gradually even for large messages in the case of put and get. Current performance detriments versus [IBM's vendor-supplied MPICH]: 1.) No optimized collectives -- all collectives are pt2pt algorithms in MPICH CH4.  There is a plan to develop optimized collectives via OFI triggered operations but that work wouldn't begin until the April-May timeframe at the earliest.  There is also a plan to make optimized pt2pt collectives available sooner. 2.) Only 1 rget injection fifo utilized per rank to pt2pt communication --- pami can utilize up all 11 to maximize internode bandwidth, you would mainly see this have an impact if you are running < 8 ranks per node and passing large messages. ==rob _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss