Remember that the kernel uses a fair amount of cpu time in the case
of TCP,
and the network portion of the transfer (where you would gain in
parallelism)
is relatively small. One sees most of the advantages of network
parallelism,
with respect to performance, when the on-host network protocol is low
relative
to the network processing, which at this stage is mostly with OS
bypass type
protocols...
Rich
On Aug 22, 2006, at 9:00 AM, Jayanta Roy wrote:
Hi Galen,
The GigE is on the ESB2. This lives on a 4GB/sec link to the MCH.
I believe we aren't really running close to the I/O bandwidth limit.
This MPI transfer uses both the ports as there are increment in RX
and TX bytes
of both eth0 and eth1. But I am getting the same bandwidth with or
without
using "--mca btl_tcp_if_include eth0" in the mpirun command line.
Are we
missing something? Or I have to go for linux ethernet channel bonding?
Regards,
Jayanta
On Tue, 22 Aug 2006, Galen M. Shipman wrote:
Jayanta,
What is your bus on this machine? If it is PCI-X 133 you are going
to be
limited, also memory bandwidth could also be the bottleneck.
Thanks,
Galen
Jayanta Roy wrote:
Hi,
In between two nodes I have dual Gigabit ethernet full duplex
links. I was
doing benchmarking using non-blocking MPI send and receive. But I am
getting only speed corresponds to one Gigabit ethernet full
duplex link
(< 2Gbps). I have checked using ifconfig, this transfer is using
both the
ports, then why I am not getting full throughput from dual Gigabit
ethernet ports? Can anyone please help me in this?
Regards,
Jayanta
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~
Jayanta Roy
National Centre for Radio Astrophysics | Phone : +91-20-25697107
Tata Institute of Fundamental Research | Fax :
+91-20-25692149 Pune
University Campus, Pune 411 007 | e-mail : j...@ncra.tifr.res.in
India
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~
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_______________________________________________
users mailing list
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http://www.open-mpi.org/mailman/listinfo.cgi/users
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~
Jayanta Roy
National Centre for Radio Astrophysics | Phone : +91-20-25697107
Tata Institute of Fundamental Research | Fax : +91-20-25692149
Pune
University Campus, Pune 411 007 | e-mail : j...@ncra.tifr.res.in
India
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~
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