The work includes:
- using llapi_layout_* interfaces to get or set the composite layout parameters (stripe count, stripe size) correctly
- improving the following I/O redistribution algorithm with PFL feature:
- Stripe-contiguous: use the LCM(lowest common multiple) of different component stripe count to calculate available cb nodes, and try to make sure each I/O write among MPI procs happens in the same component extent
- File-contiguous: use the max. or LCM of component stripe size as the common stripe size to keep the stripe alignment in each write.
The patch will be submitted to MPICH finally.