[Beowulf] mpi slow pairs

[Michael Di Domenico]

On Fri, Aug 29, 2014 at 3:26 PM, Håkon Bugge <h-bugge at online.no> wrote:
> Hmm, are all pairs going through the spine? If not, look up the parking-lot
> problem. Håkon

i believe all the pairs do pass through a spine.  i'm not familiar
with the "parking-lot problem", i'll google it, but suspect a
bazillion hits will come back


> Sendt fra min HTC
>
> ----- Reply message -----
> Fra: "Michael Di Domenico" <mdidomenico4 at gmail.com>
> Til: "Beowulf Mailing List" <Beowulf at beowulf.org>
> Emne: [Beowulf] mpi slow pairs
> Dato: fre., aug. 29, 2014 18:09
>
>
>
> On Fri, Aug 29, 2014 at 11:38 AM, John Hearns <John.Hearns at viglen.co.uk>
> wrote:
>>> Also have you run  ibdiagnet to see if anything is flagged up?
>>
>> i've run a multitude of ib diags on the machines, but nothing is popping
>> out as wrong.  what's weird is that it's only certain pairing of machines
>> not any one machine in general.
>>
>> Would that then be a problem in one of the blades or a part of the switch?
>
> not sure yet, i think on the spine modules in the switch is silently
> failing to send traffic a full speed, but i've not been able to
> "prove" this yet.
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