From: Adam Leko (leko_at_hcs_dot_ufl_dot_edu)
Date: Sat Oct 07 2006 - 15:22:49 PDT
What's the best way to run Berkeley UPC on a Cray XD1? I notice from the GASNet conduit there is support for the MPI and SMP conduits. I think the built-in MPICH on the XD1 takes advantage of the RapidArray, and it seems to have pretty good performance (advertised 1.7us latency, and on a chassis I've seen even less in unscientific measurements). The MPI conduit currently has OK performance but has some anomolies which might be due to the polling-based implementation interacting with the specialized MPICH version. Are there any other options that better suit the XD1 hardware? I'm not sure if RapidArray is going to make it into any future Cray products, but if so it seems worth supporting. Our lab is interested because we might be doing something with both UPC and reconfigurable computing, and a platform with excellent RC and good UPC support is interesting. Some notes: The Cray website claims support for SHMEM, but it is provided via GPSHMEM and a BUPC -> SHMEM conduit -> GPSHMEM -> ARMCI solution seems kind of gross. There's also a "Global Arrays" interface which looks like it is also layered above ARMCI. However, either option seems better suited than the MPI conduit. (As a side note, anyone with an HCS lab account can access our XD1 at xd1.hcs.ufl.edu but let us know before you pound it with long jobs) -Adam Leko