[openib-general] IPoIB Question

[Greg Lindahl]

On Mon, Oct 23, 2006 at 07:53:06AM -0500, Hubbell, Sean C Contractor/Decibel wrote:

>   I currently have several applications that uses a legacy IPv4 protocol
> and I use IPoIB to utilize my infiniband network which works great. I
> have completed some timing and throughput analysis and noticed that I do
> not get very much more if I use an infiniband network interface than
> using my GigE network interface.

You might want to note that different InfinBand implementations have
quite different performance of IPoIB, especially for UDP.

Another issue is that IPoIB has quite different performance with
different Linux kernels. This is especially evident for TCP, although
you can use SDP to accelerate TCP sockets and avoid this issue.

> My question is, am I using IPoIB correctly or are these the typical
> numbers that everyone is seeing?

It is certainly the case that there are some message patterns and
situations for which InfiniBand is not much of an improvement over
gigE.

-- greg