[ofa-general] [PATCH] ipoib: refresh path when remote lid changes

[Hal Rosenstock]

On Fri, Jul 31, 2009 at 2:56 PM, Yossi Etigin <yosefe at voltaire.com> wrote:

> On 31/07/09 19:58, Todd Rimmer wrote:
> >> Yossi Etigin wrote:
> >
> >> What if we query the remote port LMC once, when the path is resolved,
> >> and then
> >> use it to mask the LID until the path is refreshed again?
> >
> > Doing the LMC query when the PathRecord query is made makes, sense.
> >
> > I assume you are proposing a query of the SA for the PortInfoRecord?
> >
> > Note that a direct query of the remote SMA would be a bad idea and has at
> least the following issues:
> > 1. There are limited VL15 queuing resources and no VL15 flow control,
> hence if multiple nodes queried the same SMA at the same time, packet loss
> could be significant which would impact SM operation as well (note how
> carefully the recent opensm work for parallel queries has had to tune
> operations to SMAs)
> > 2. If MKey security is enabled, the client will not (and should not) know
> the MKey of the remote SMA and hence can't make a query.
> > 3. The intent of the IB Architecture is for the SM to be the only entity
> which interacts with SMAs.  A handful of diagnostic tools (like ibdiagnet)
> may be an acceptable exception, but it would not be recommended to make
> non-SM queries of an SMA as part of a normal protocol.
> >
>
> Actually I wasn't sure which is better, but given all these issues SM
> should be the one and not the SA.
>
>
Do you mean SA rather than SM ?
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