Thanks George,
I am selecting Ethernet device (em1) in mpirun script.
Here is ifconfig output:
em1 Link encap:Ethernet HWaddr E0:DB:55:FD:38:46
inet addr:10.30.10.121 Bcast:10.30.255.255 Mask:255.255.0.0
inet6 addr: fe80::e2db:55ff:fefd:3846/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1537270190 errors:0 dropped:0 overruns:0 frame:0
TX packets:136123598 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:309333740659 (288.0 GiB) TX bytes:143480101212 (133.6
GiB)
Memory:91820000-91840000
Ifconfig uses the ioctl access method to get the full address information,
which limits hardware addresses to 8 bytes.
Because Infiniband address has 20 bytes, only the first 8 bytes are
displayed correctly.
Ifconfig is obsolete! For replacement check ip.
ib0 Link encap:InfiniBand HWaddr
80:00:00:03:FE:80:00:00:00:00:00:00:00:00:00:00:00:00:00:00
inet addr:10.32.10.121 Bcast:10.32.255.255 Mask:255.255.0.0
inet6 addr: fe80::211:7500:70:6ab4/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:2044 Metric:1
RX packets:33621 errors:0 dropped:0 overruns:0 frame:0
TX packets:365 errors:0 dropped:5 overruns:0 carrier:0
collisions:0 txqueuelen:256
RX bytes:1882728 (1.7 MiB) TX bytes:21920 (21.4 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:66889 errors:0 dropped:0 overruns:0 frame:0
TX packets:66889 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:19005445 (18.1 MiB) TX bytes:19005445 (18.1 MiB)
> Date: Wed, 10 Sep 2014 00:06:51 +0900
> From: George Bosilca <bosi...@icl.utk.edu>
> To: Open MPI Users <us...@open-mpi.org>
> Subject: Re: [OMPI users] Forcing OpenMPI to use Ethernet interconnect
> instead of InfiniBand
>
> Look at your ifconfig output and select the Ethernet device (instead of the
> IPoIB one). Traditionally the name lack any fanciness, most distributions
> using eth0 as a default.
>
> George.
>
>
> On Tue, Sep 9, 2014 at 11:24 PM, Muhammad Ansar Javed <
> muhammad.an...@seecs.edu.pk> wrote:
>
> > Hi,
> >
> > I am currently conducting some testing on system with Gigabit and
> > InfiniBand interconnects. Both Latency and Bandwidth benchmarks are doing
> > well as expected on InfiniBand interconnects but Ethernet interconnect is
> > achieving very high performance from expectations. Ethernet and
> InfiniBand
> > both are achieving equivalent performance.
> >
> > For some reason, it looks like openmpi (v1.8.1) is using the InfiniBand
> > interconnect rather than the Gigabit or TCP communication is being
> emulated
> > to use InifiniBand interconnect.
> >
> > Here are Latency and Bandwidth benchmark results.
> > #---------------------------------------------------
> > # Benchmarking PingPong
> > # processes = 2
> > # map-by node
> > #---------------------------------------------------
> >
> > Hello, world. I am 1 on node124
> > Hello, world. I am 0 on node123
> > Size Latency (usec) Bandwidth (Mbps)
> > 1 1.65 4.62
> > 2 1.67 9.16
> > 4 1.66 18.43
> > 8 1.66 36.74
> > 16 1.85 66.00
> > 32 1.83 133.28
> > 64 1.83 266.36
> > 128 1.88 519.10
> > 256 1.99 982.29
> > 512 2.23 1752.37
> > 1024 2.58 3026.98
> > 2048 3.32 4710.76
> >
> > I read some of the FAQs and noted that OpenMPI prefers the faster
> > available interconnect. In an effort to force it to use the gigabit
> > interconnect I ran it as follows
> >
> > 1. mpirun -np 2 -machinefile machines -map-by node --mca btl tcp --mca
> > btl_tcp_if_include em1 ./latency.ompi
> > 2. mpirun -np 2 -machinefile machines -map-by node --mca btl tcp,self,sm
> > --mca btl_tcp_if_include em1 ./latency.ompi
> > 3. mpirun -np 2 -machinefile machines -map-by node --mca btl ^openib
> --mca
> > btl_tcp_if_include em1 ./latency.ompi
> > 4. mpirun -np 2 -machinefile machines -map-by node --mca btl ^openib
> > ./latency.ompi
> >
> > None of them resulted in a significantly different benchmark output.
> >
> > I am using OpenMPI by loading module on clustered environment and don't
> > have admin access. It is configured for both TCP and OpenIB (confirmed
> from
> > ompi_info). After trying all above mentioned methods without success I
> > installed OpenMPI v1.8.2 in my home directory and disable openib with
> > following configuration options
> >
> > --disable-openib-control-hdr-padding --disable-openib-dynamic-sl
> > --disable-openib-connectx-xrc --disable-openib-udcm
> > --disable-openib-rdmacm --disable-btl-openib-malloc-alignment
> > --disable-io-romio --without-openib --without-verbs
> >
> > Now, openib is not enabled (confirmed from ompi_info script) and there is
> > no "openib.so" file in $prefix/lib/openmpi directory as well. Still,
> above
> > mentioned mpirun commands are getting the same latency and bandwidth as
> > that of InfiniBand.
> >
> > I tried mpirun in verbose mode with following command and here is the
> > output
> >
> > Command:
> > mpirun -np 2 -machinefile machines -map-by node --mca btl tcp --mca
> > btl_base_verbose 30 --mca btl_tcp_if_include em1 ./latency.ompi
> >
> > Output:
> > [node123.prv.sciama.cluster:88310] mca: base: components_register:
> > registering btl components
> > [node123.prv.sciama.cluster:88310] mca: base: components_register: found
> > loaded component tcp
> > [node123.prv.sciama.cluster:88310] mca: base: components_register:
> > component tcp register function successful
> > [node123.prv.sciama.cluster:88310] mca: base: components_open: opening
> btl
> > components
> > [node123.prv.sciama.cluster:88310] mca: base: components_open: found
> > loaded component tcp
> > [node123.prv.sciama.cluster:88310] mca: base: components_open: component
> > tcp open function successful
> > [node124.prv.sciama.cluster:90465] mca: base: components_register:
> > registering btl components
> > [node124.prv.sciama.cluster:90465] mca: base: components_register: found
> > loaded component tcp
> > [node124.prv.sciama.cluster:90465] mca: base: components_register:
> > component tcp register function successful
> > [node124.prv.sciama.cluster:90465] mca: base: components_open: opening
> btl
> > components
> > [node124.prv.sciama.cluster:90465] mca: base: components_open: found
> > loaded component tcp
> > [node124.prv.sciama.cluster:90465] mca: base: components_open: component
> > tcp open function successful
> > Hello, world. I am 1 on node124
> > Hello, world. I am 0 on node123
> > Size Latency(usec) Bandwidth(Mbps)
> > 1 4.18 1.83
> > 2 3.66 4.17
> > 4 4.08 7.48
> > 8 3.12 19.57
> > 16 3.83 31.84
> > 32 3.40 71.84
> > 64 4.10 118.97
> > 128 3.89 251.19
> > 256 4.22 462.77
> > 512 2.95 1325.71
> > 1024 2.63 2969.49
> > 2048 3.38 4628.29
> > [node123.prv.sciama.cluster:88310] mca: base: close: component tcp closed
> > [node123.prv.sciama.cluster:88310] mca: base: close: unloading component
> > tcp
> > [node124.prv.sciama.cluster:90465] mca: base: close: component tcp closed
> > [node124.prv.sciama.cluster:90465] mca: base: close: unloading component
> > tcp
> >
> > Moreover, same benchmark applications using MPICH are working fine on
> > Ethernet and achieving expected Latency and Bandwidth.
> >
> > How can this be fixed?
> >
> > Thanks for help,
> >
> > --Ansar
>
--
Regards
Ansar Javed
HPC Lab
SEECS NUST
Contact: +92 334 438 9394
Skype: ansar.javed.859
Email: muhammad.an...@seecs.edu.pk
