[Beowulf] How to debug error with Open MPI 3 / Mellanox / Red Hat?

Faraz Hussain info at feacluster.com
Tue Apr 30 12:57:27 PDT 2019


Thanks, after buidling openmpi 4 from source, it now works! However it  
still gives this message below when I run openmpi with verbose setting:

No OpenFabrics connection schemes reported that they were able to be
used on a specific port.  As such, the openib BTL (OpenFabrics
support) will be disabled for this port.

   Local host:           lustwzb34
   Local device:         mlx4_0
   Local port:           1
   CPCs attempted:       rdmacm, udcm

However, the results from my latency and bandwith tests seem to be  
what I would expect from infiniband. See:

[hussaif1 at lustwzb34 pt2pt]$  mpirun -v -np 2 -hostfile ./hostfile  
./osu_latency
# OSU MPI Latency Test v5.3.2
# Size          Latency (us)
0                       1.87
1                       1.88
2                       1.93
4                       1.92
8                       1.93
16                      1.95
32                      1.93
64                      2.08
128                     2.61
256                     2.72
512                     2.93
1024                    3.33
2048                    3.81
4096                    4.71
8192                    6.68
16384                   8.38
32768                  12.13
65536                  19.74
131072                 35.08
262144                 64.67
524288                122.11
1048576               236.69
2097152               465.97
4194304               926.31

[hussaif1 at lustwzb34 pt2pt]$  mpirun -v -np 2 -hostfile ./hostfile ./osu_bw
# OSU MPI Bandwidth Test v5.3.2
# Size      Bandwidth (MB/s)
1                       3.09
2                       6.35
4                      12.77
8                      26.01
16                     51.31
32                    103.08
64                    197.89
128                   362.00
256                   676.28
512                  1096.26
1024                 1819.25
2048                 2551.41
4096                 3886.63
8192                 3983.17
16384                4362.30
32768                4457.09
65536                4502.41
131072               4512.64
262144               4531.48
524288               4537.42
1048576              4510.69
2097152              4546.64
4194304              4565.12

When I run ibv_devinfo I get:

[hussaif1 at lustwzb34 pt2pt]$ ibv_devinfo
hca_id: mlx4_0
         transport:                      InfiniBand (0)
         fw_ver:                         2.36.5000
         node_guid:                      480f:cfff:fff5:c6c0
         sys_image_guid:                 480f:cfff:fff5:c6c3
         vendor_id:                      0x02c9
         vendor_part_id:                 4103
         hw_ver:                         0x0
         board_id:                       HP_1360110017
         phys_port_cnt:                  2
         Device ports:
                 port:   1
                         state:                  PORT_ACTIVE (4)
                         max_mtu:                4096 (5)
                         active_mtu:             1024 (3)
                         sm_lid:                 0
                         port_lid:               0
                         port_lmc:               0x00
                         link_layer:             Ethernet

                 port:   2
                         state:                  PORT_DOWN (1)
                         max_mtu:                4096 (5)
                         active_mtu:             1024 (3)
                         sm_lid:                 0
                         port_lid:               0
                         port_lmc:               0x00
                         link_layer:             Ethernet

I will ask the openmpi mailing list if my results make sense?!


Quoting Gus Correa <gus at ldeo.columbia.edu>:

> Hi Faraz
>
> By all means, download the Open MPI tarball and build from source.
> Otherwise there won't be support for IB (the CentOS Open MPI packages most
> likely rely only on TCP/IP).
>
> Read their README file (it comes in the tarball), and take a careful look
> at their (excellent) FAQ:
> https://www.open-mpi.org/faq/
> Many issues can be solved by just reading these two resources.
>
> If you hit more trouble, subscribe to the Open MPI mailing list, and ask
> questions there,
> because you will get advice directly from the Open MPI developers, and the
> fix will come easy.
> https://www.open-mpi.org/community/lists/ompi.php
>
> My two cents,
> Gus Correa
>
> On Tue, Apr 30, 2019 at 3:07 PM Faraz Hussain <info at feacluster.com> wrote:
>
>> Thanks, yes I have installed those libraries. See below. Initially I
>> installed the libraries via yum. But then I tried installing the rpms
>> directly from Mellanox website (
>> MLNX_OFED_LINUX-4.5-1.0.1.0-rhel7.5-x86_64.tar ). Even after doing
>> that, I still got the same error with openmpi. I will try your
>> suggestion of building openmpi from source next!
>>
>> root at lustwzb34:/root # yum list | grep ibverbs
>> libibverbs.x86_64                     41mlnx1-OFED.4.5.0.1.0.45101
>> libibverbs-devel.x86_64               41mlnx1-OFED.4.5.0.1.0.45101
>> libibverbs-devel-static.x86_64        41mlnx1-OFED.4.5.0.1.0.45101
>> libibverbs-utils.x86_64               41mlnx1-OFED.4.5.0.1.0.45101
>> libibverbs.i686                       17.2-3.el7
>> rhel-7-server-rpms
>> libibverbs-devel.i686                 1.2.1-1.el7
>> rhel-7-server-rpms
>>
>> root at lustwzb34:/root # lsmod | grep ib
>> ib_ucm                 22602  0
>> ib_ipoib              168425  0
>> ib_cm                  53141  3 rdma_cm,ib_ucm,ib_ipoib
>> ib_umad                22093  0
>> mlx5_ib               339961  0
>> ib_uverbs             121821  3 mlx5_ib,ib_ucm,rdma_ucm
>> mlx5_core             919178  2 mlx5_ib,mlx5_fpga_tools
>> mlx4_ib               211747  0
>> ib_core               294554  10
>>
>> rdma_cm,ib_cm,iw_cm,mlx4_ib,mlx5_ib,ib_ucm,ib_umad,ib_uverbs,rdma_ucm,ib_ipoib
>> mlx4_core             360598  2 mlx4_en,mlx4_ib
>> mlx_compat             29012  15
>>
>> rdma_cm,ib_cm,iw_cm,mlx4_en,mlx4_ib,mlx5_ib,mlx5_fpga_tools,ib_ucm,ib_core,ib_umad,ib_uverbs,mlx4_core,mlx5_core,rdma_ucm,ib_ipoib
>> devlink                42368  4 mlx4_en,mlx4_ib,mlx4_core,mlx5_core
>> libcrc32c              12644  3 xfs,nf_nat,nf_conntrack
>> root at lustwzb34:/root #
>>
>>
>>
>> > Did you install libibverbs  (and libibverbs-utils, for information and
>> > troubleshooting)?
>>
>> > yum list |grep ibverbs
>>
>> > Are you loading the ib modules?
>>
>> > lsmod |grep ib
>>
>>





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