Yes, the buffer was being re-used. No we didnt try to benchmark it with netpipe
and other stuffs. But the program was pretty simple. Do you think, I need to
test it with bigger chunks (>8MB) for communication.?We also tried
manipulating eager_limit and min_rdma_sze, but no success.NeerajOn Fri, 12 Oct
2007 13:00:10 +0200 Open MPI Users wrote Hello, > The code was
pretty simple. I was trying to send 8MB data from one > rank to other in
a loop(say 1000 iterations). And then i was taking the > average of time
taken and was calculating the bandwidth. > > The above logic i
tried with both mpirun-with-mca-parameters and without > any parameters.
And to my surprise, the performance was degrading when i > was trying to
manipulate. That sounds strange. So did you re-use the communication buffers?
Did you try to run some existing benchmarks like Netpipe [1], IMB or Netgauge
[2]? > Now I have another question in mind. Is it possible to have IB
Hardware > Multicast implementation in OpenMPI? I have gone through the
> issues/challenges for the same, but also read couple of people who have
> successfully done it for Ethernet/Giga-bit Ethernet and IPoIB ofcourse
in > experimental stage. Actually i want to contribute for it in OpenMPI
and > need the help for the same. As far as I know, there are two
groups/people working on this. Andy Friedley implements a \"traditional\" ACK
based approach (like the one that the OSU folks published about some time ago)
and I implemented a new idea for extreme scale (see \"A practically
constant-time MPI Broadcast Algorithm for large-scale InfiniBand Clusters with
Multicast\" [3]). I know that my version is still unstable and has some
problems. But I\'m working on this. Best, Torsten [1]:
http://www.scl.ameslab.gov/netpipe/ [2]:
http://www.unixer.de/research/netgauge/ [3]:
https://www.unixer.de/publications/#hoefler-cac07 -- bash$ :(){
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