We studied the performance overhead of ADIO on PIOFS and PFS by using two test programs and one real production parallel application. Performance studies of ADIO on Unix and NFS are currently in progress.
We used the IBM SP at Argonne and the Intel Paragon at Caltech. The parallel I/O systems on these two machines were configured as follows during our experiments. On the SP, there were eight I/O server nodes for PIOFS, each with 3Gbytes of local SCSI disks, and the operating system was AIX 3.2.5. On the Paragon, there were 16 I/O nodes for PFS, each connected to a 4.8-Gbyte RAID-3 disk array, and the operating system was Paragon/OSF R1.3.3. On both machines, users were not allowed to run compute jobs on the I/O nodes.
The performance results presented below are from an implementation of ADIO using functions, not macros; the results may be slightly better if we use macros.