Catwalk-ROMIO: A Cost-Effective MPI-IO

The nature of highly parallelized parallel file access which often consists of lots of fine grain, non-contiguous I/O requests, can degrade the I/O performance severely. To tackle this problem, a novel technique to maximize the bandwidth of the MPI-IO is proposed. This proposed technique is utilize a ring communication topology. This technique is implemented as an ADIO device of ROMIO, named Catwalk-ROMIO, and evaluated. The evaluation shows that Catwalk-ROMIO utilizing only one disk can exhibit comparable performance with parallel files systems, PVFS2 and Lustre, utilizing several file servers and disks. The evaluation also shows that Catwalk-ROMIO performance is almost independent from file access patterns, in contrast to the performance of parallel file systems performing only well with collective I/O. Catwalk-ROMIO only requires TCP/IP network for the ring communication topology and one file server which are common in HPC clusters without any additional cost. Thus, Catwalk-ROMIO is considered to be a very cost-effective MPI-IO implementation.