P_[ACTION]_shared

Concurrent access to a common file by all participating processes, with a shared file pointer. See the basic definitions and a schematic view of the pattern below.

P_[ACTION]_shared Definition

Property

Description

Measured pattern

As symbolized in figure I/O benchmarks, aggregation for output

Elementary I/O action

As symbolized in the figure below. In this figure, Nproc is the number of processes.

MPI routines for the blocking mode

MPI_File_write_at/MPI_File_read_at

MPI routines for the nonblocking mode

MPI_File_iwrite_at/MPI_File_iread_at

etype

MPI_BYTE

File type

MPI_BYTE

MPI data type

MPI_BYTE

Reported timings

t (in μsec) as indicated in the figure I/O benchmarks, aggregation for output, aggregate and non-aggregate for the Write flavor.

Reported throughput

x/t, aggregate and non-aggregate for the Write flavor

P_[ACTION]_shared Pattern