[ofa-general] PATCH [0/3] osm: adding root and compute node guid files options for fat-tree

[Hal Rosenstock]

On Fri, 2007-06-15 at 16:59, Sasha Khapyorsky wrote:
> On 16:39 Fri 15 Jun     , Hal Rosenstock wrote:
> > On Thu, 2007-06-14 at 09:45, Sasha Khapyorsky wrote:
> > > On 15:36 Thu 14 Jun     , Yevgeny Kliteynik wrote:
> > > >  Sasha Khapyorsky wrote:
> > > > > Hi Yevgeny,
> > > > > On 11:19 Thu 14 Jun     , Yevgeny Kliteynik wrote:
> > > > >>  The following three patches are adding root and compute node guid files
> > > > >>  options for fat-tree routing,
> > > > > Is there any reason to not share root guids file option with up/down?
> > > > 
> > > >  There are two new options for fat-tree: roots and compute nodes (CN).
> > > >  These two will be very "tightly coupled" and would have more implication
> > > >  on the routing than in case of up/dn roots. For instance, having root
> > > >  file but not CN file means that the topology doesn't have to be pure 
> > > >  fat-tree,
> > > >  but all the CAs are considered CNs and have to be on the same level of the 
> > > >  tree.
> > > >  And there is similar implication of all the combinations of these two 
> > > >  options.
> > > > 
> > > >  Because of this coupling I wanted to differentiate these two options from
> > > >  the up/dn roots.
> > > > 
> > > >  Thoughts?
> > > 
> > > I still not have strong option about two options against common one.
> > 
> > Me neither.
> > 
> > > Hypothetically if in some days we will implement routing engine chains
> > > (so failed algo will fallback to next in chain and not just to default)
> > > separate options could be useful.
> > 
> > So is this a(nother) reason to keep the roots separate or would that be
> > dealt with when the routing fallback strategy changes ?
> 
> It is yet hypothetical. Currently I don't see a strong practical reasons
> to have two separate root guids file options for up/down and fat-tree,
> but guess this is minor and not showstopper.

Wouldn't a current practical reason be switching between up/down and fat
tree and they each have different roots ? Is that a real scenario ?

-- Hal

> Sasha