[mvapich-discuss] MVAPICH2 with MV2_USE_RDMA_CM=1 flag

[Malek Musleh]

Hi,

I am testing the OSU_benchmarks over my infiniband setup, some machines
which have connectx-gen2 and others gen3. I recently came across this fag
in the user guide, and thought it should impact the performance results
(improve it) since it would be using RDMA instead of IPoIB.

At first, it did seem like for a few cases (test runs) I was generally
seeing an improvement (for the large message sizes), but overall it does
not seem like it, which seems to match the discussion in this thread:

http://mail.cse.ohio-state.edu/pipermail/mvapich-discuss/2008-May/001644.html

If it is only used in the setup part, what general benefit would there to
be use the flag? Similarly, what benefit would there be to use the
MV2_USE_RDMAOE=1 flag?

I have only been using 2 test nodes at a time (for the moment), and using
revision 1.8r527.

Generally speaking, are specific benchmarks (osu_passive_acc_latency vs.
osu_acc_latency) likely/should benefit, or perhaps intra-node tests vs.
inter-node?

Thanks,

Malek
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.cse.ohio-state.edu/pipermail/mvapich-discuss/attachments/20130805/0e38ff0c/attachment.html