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Subject: Re: [OMPI devel] RFC: Linuxes shipping libibverbs
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2008-05-29 09:54:29

On May 29, 2008, at 3:27 AM, Pavel Shamis (Pasha) wrote:

>> I got some more feedback from Roland off-list explaining that if /
>> sys/
>> class/infiniband does exist and is non-empty and /sys/class/
>> infiniband_verbs/abi_version does not exist, then this is
>> definitely a
>> case where we want to warn because it implies that config is screwed
>> up -- RDMA devices are present but not usable.
> Is it possible that /sys/class/infiniband directory exist and it is
> empty ? In which cases ?

Roland consistently said "...and not empty" in e-mails to me, so
that's what I assumed.

However, Pasha just did a test: on a machine with a ConnectX HCA, he
manually removed the mlx4 drive and started the openibd service. /sys/
class/infiniband was created, but it was empty.

I guess this is a situation that we want to warn about -- we can
simplify the whole deal by making the overriding assumption: if the
drivers are loaded at all (such that /sys/class/infiniband/ exists at
all), OMPI should expect to be able to find some RDMA devices. If it
doesn't find any, it should issue a warning.

Jeff Squyres
Cisco Systems