[Users] DF-DN: A new Deadlock-free "Routing Engine" for OpenSM

[Timo Schneider]

Hello,

in the last few months we created a new deadlock-free routing module
for OpenSM. It is based on the idea of incrementing the VL at every
hop, as opposed to the traditional (in OpenSM at least) approach of
layering entire paths into different VLs. Thus the number of VLs
required is bounded by the network diameter, which is often lower than
the number of VLs required by DFSSSP or LASH for low-diameter networks.
Furthermore our algorithm is a factor of five faster than DFSSSP (while
providing the same routing) and two orders of magnitude faster than
LASH for networks with ~1000 switches.

Our DF-DN algorithm can be combined with any routing engine (which is
based on shortest path routing), we implemented the combination DF-
DN+MinHop and DF-DN+SSSP.

We have described and evaluated our approach in a paper which will
appear at the next Hot Interconnects conference, a preprint is also
available here: 
https://spcl.inf.ethz.ch/Research/Scalable_Networking/DFDN/

Our code is available to the public. I would like to get feedback from
the maintainers of OpenSM if there is any interest of merging our patch
into an upcoming official release of OpenSM.

Currently I am unclear about the procedure of contributing to OpenSM,
thus I hope the right person reads this list or someone can direct me
towards him/her.

Regards,
Timo