[Lustre-discuss] Limits for o2ib lnet network numbers

[Rick Mohr]

On Thu, 2012-08-09 at 15:14 +0800, Liang Zhen wrote:
> No Jira ticket yet, reason of the potential performance issue is
> straightforward, it's because all LNet NIs are linked on a plain list,
> and we need scan the whole list for each sending/receiving, it's not
> an issue for a few networks, but it could be problematic for hundreds
> or tens.

Are there any whitepapers or other docs which quantify the potential
performance issue?  I can easily see how this might be a problem for a
hundred networks, but given that I am not likely to have a setup with
that many networks, I probably wouldn't lose any sleep over it.
However, if there can be performance issues with as few as 10 networks,
then this becomes much more relevant and may require me to rethink some
of my choices.  I'd appreciate any information which could help me with
those decisions.

-- 
Rick Mohr
HPC Systems Administrator
National Institute for Computational Sciences
http://www.nics.tennessee.edu/