Intel® MPI Benchmarks User Guide and Methodology Description

# Memory and Disk Space Requirements

The table below lists memory requirements for benchmarks run with the default settings (standard mode) and with the user-defined settings (optional mode). In this table:

- Q is the number of active processes.

- X is the maximal size of the passing message.

Benchmarks | Standard Mode | Optional Mode
--- | --- | ---
`Alltoall` | Q*8 MB | Q*2X bytes
`Allgather, Allgatherv` | (Q+1)*4 MB | (Q+1)*X bytes
`Exchange` | 12 MB | 3X bytes
All other MPI-1 benchmarks | 8 MB | 2X bytes
`IMB-EXT` | 80 MB | 2 max`(X,OVERALL_VOL)` bytes
`IMB-IO` | 32 MB | 3X bytes
`Ialltoall`, `Ialltoall_pure` | Q*8 MB | Q*2X bytes
`Iallgather`, `Iallgatherv`, `Iallgather_pure`, `Iallgatherv_pure` | (Q+1)*4 MB | (Q+1)*X bytes
All other `IMB-NBC` benchmarks | 8 MB | 2X bytes
`Compare_and_swap` | 12 B | 12 B
`Exchange_put`, `Exchange_get` | 16 MB | 4X bytes
All other `IMB-RMA` benchmarks | 8 MB | 2X bytes

### Note

If you do not select the `-cache` flag, add 2X cache size to all of the above.

For `IMB-IO` benchmarks, make sure you have enough disk space available:

- 16MB in the standard mode

- max`(X,OVERALL_VOL)` bytes in the optional mode

For instructions on enabling the optional mode, see Parameters Controlling Intel® MPI Benchmarks.