[mvapich-discuss] MVAPICH2 Performance Evaluation

[Greg Lindahl]

On Tue, Oct 10, 2006 at 11:09:19PM -0400, Amit H Kumar wrote:

> Just Curious, Since the switch that we have is InfinIO 3000 (a speed of
> 10Gbps = 1.16GBytes/s ).

The link speed for IB is quoted as 10 Gbps, but after 10b/8b encoding
the actual data rate is 8 Gbps, e.g. 8 x 10^9 bit/s. So that's 1 Gbyte/s
(where giga = 10^9) or 0.931 Gbyte/s (where giga = 2^30).

Not that this answers your question ;-) but it's worth mentioning as
lots of people don't know it.

> How do I intepret these results with the Specification of Peak System
> bandwidth: 640 Gb/s = approx. 74 GB/s; I am no where close to that.

This is the total theoretical bandwidth of all of the ports on the
switch combined: 32 ports x 10 Gbps in each direction.

-- greg