UPC Parallel I/O Library

Application Needs Efficient thread access to files in parallel for Reading/Writing data (collectively, independently) Scratch pads Out-of-core computations Logs and check-pointing Access by each thread to non-contiguous data objects in file Other?

A Preliminary Proposal for UPC Parallel I/O API Maintains C/Unix file view, sequence of bytes Leverages C/Unix I/O syntax for open, read, write, fopen, fread, .. etc. Leverages UPC data types (e.g. blocked shared arrays under the UPC memory model) to define which thread reads or write which data Many other issues are still open

Plan of Attack Finish Parallel I/O survey and Develop Requirement (April) Complete the current proposal (April) Review the proposal in light of Parallel I/O APIs, such as MPI-IO and PFS, and the UPC collective operations group

Plan of Attack cont. Consider synchronous and asynchronous accesses Shared and private file pointers for coordinated and independent accesses Synchronization worked out Should we support variable length records? This may be tricky