[ofa-general] Re: [PATCH OpenSM 0/3] Fat Tree - Routing between non-CN nodes

[Sasha Khapyorsky]

On 20:48 Sat 07 Feb     , Nicolas Morey-Chaisemartin wrote:
> >
> > "IO" is specific for your setup. Could we find more generic name for such
> > nodes?
> >
> >   
> Sure. Any ideas?

No, I didn't think about it.

> >> The max_reverse_hops gives the number of time IO nodes (described by 
> >> io_guid_file) are allowed to use a switch backward.
> >>     
> >
> > Don't those two options duplicate each others somehow? If we want to
> > connect io nodes anyway, why max_reverse_hops should be important?
> >   
> Because we may not want to connect all of them to all the nodes. By
> specifying a small max_reverse_hop you can restrain (depending on your
> topology) the effect of the io_guid_file so an "IO" node will only see
> the closests "IO" node through reverse routes but not all of them
> As the effect on credit loop is not certain yet, I think the less
> reverse route we create, the better it is.
> > Or probably instead of having io nodes guids list we prefer to connect
> > everything N hops from roots? Then sort of --connect-roots extension
> > (--connect-roots=3) could work. No?
> >
> >   
> That should work too but it is less flexible than io_guid_file for
> tweaking the configuration and have the best routing scheme.
> >> According to my tests this has absolutely no effects on regular routing and 
> >> manages to connect the io nodes together, if max_reverse_hops is big 
> >> enough.
> >>
> >> This is a first draft for this feature. I'd be happy to have some feedback 
> >> about how to upgrade it and make it as clean as possible, wether it is 
> >> integrated in the mainstream or not.
> >>     
> >
> > Since this functionality is optional, useful and shouldn't change a
> > default behavior it can be suitable for main stream IMO.
> >
> > Sasha
> Okay, I'll fix the indentation and few coding style error. There is also
> a bug in the current patch as the hops counter are not set to the right
> value when creating route which had reverse hops number of reverse
> hops*2 should be added.
> 
> I'll have to rewrite the patches so they work with the current HEAD.
> Specially with the option system changes it won't merge cleanly.

Use 'git-rebase master <yourbranch>' - it does the job with only two
trivial conflicts.

Sasha