[ofa-general] Re: [PATCH] opensm: preserve base lid routes

[Hal Rosenstock]

On Thu, 2008-06-12 at 14:33 +0300, Sasha Khapyorsky wrote:
> On 03:59 Thu 12 Jun     , Hal Rosenstock wrote:
> > 
> > Would you elaborate on the motivation behind the requirement to
> > maintain/preserve the base LID routing ?
> 
> I see couple advantages:
> 
> 1. Application which works on base LIDs only will not be affected by LMC

Yes; that's the obvious one.

> 2. Changing LMC on a fabric will not change routing paths (when LIDs are
> not reassigned)

That's when LMC is reduced rather than increased.

> 3. Finally it does better balancing for secondary LIDs ("port
> offsetting")

Isn't that accomodated in the patch but separate from the base LID
preservation ?

Preserving/maintaining base LIDs is a policy decision and perhaps this
should be an option with this as the default. For some balancing all
paths might be more important that not disrupting base LID traffic.

-- Hal

> Sasha