Checkpoint-Restart: Proprietary Hardware and the "Spiderweb API"

This summary describes a package to transparently checkpoint and restart applications which run over Infiniband. Infiniband is rapidly growing as a high-speed interconnect, even appearing on departmental clusters. The current work grew out of the needs of high performance computing. As of November, 2010, 43% of the TOP500 supercomputers run Infiniband. However, the ability to checkpoint immediately provides access to a poor man's reversible debugger. Using our DMTCP (Distributed MultiThreaded CheckPointing, http://dmtcp.sf.net), we can already checkpoint a GDB session today: if we have executed 100 commands since the last checkpoint, we can undo the last instruction by restarting the checkpoint and going forward 99 commands. Since many apps access Infiniband through MPI (Message Passing Interface) instead of direct communication with Infiniband, we also integrated DMTCP into the OpenMPI dialect so as to transparently debug an MPI-based application.