UM version4.5 GCOM
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Comparing the use of different versions of GCOM with UM Version4.5
Preamble
Versions of GCOM are available from:
GCOMv3.1
- Compatible with UMv4.5 without any code changes.
- Principle benefit is a better all-to-all routine (used in gathering output data to the master process).
DDR Infiniband & Intel Harpertown
- For Bristol's BlueCrystal-phase2 machine:
| IMB ping-pong message latency | |||
|---|---|---|---|
| 0 bytes | 128 bytes | 1024 bytes | |
| between nodes | ~3.0us | ~3.8us | ~6.0us |
| %time - 8x8 decomp. | ||
|---|---|---|
| subruotine | GCOMv2.9b5 | GCOMv3.1 |
| gatherfield | 12% | ~5% |
| swapbounds | 18% | ~15% |