[Beowulf] Intel buys QLogic InfiniBand business

Mark Hahn hahn at mcmaster.ca
Mon Jan 30 07:04:53 PST 2012

>> out of curiosity, has anyone set up a head-to-head comparison
>> (two or more identical machines, both with a Qlogic and a Mellanox card of
>> the same vintage)?
>> There was a bit of discussion of InfiniBand benchmarking in this thread
> and it seems it would be helpful to the casual readers like myself to have
> a few references to benchmarking toolkits and actual results.
> Most often reported results are gathered with either Netpipe from Ames or
> Intel MPI Benchmark (formerly known as Palas Benchmark) or OSU
> Micro-benchmarks.
> Searching the web produced a recent report from Swiss CSCS where a Mellanox
> ConnectX3 QDR HCA with a Mellanox switch is set against a Qlogic 7300 QDR
> HCA connected to a Qlogic switch.
> http://www.cscs.ch/fileadmin/user_upload/customers/cscs/Tech_Reports/Performance_Analysis_IB-QDR_final-2.pdf

as far as I can tell, this paper mainly says "a coalescing stack delivers
benchmark results showing a lot higher bandwidth and message rate than a
non-coalescing stack."  the comment on figure 8:

     To some extent, the environment variables mentioned before
     contribute to this outstanding result

which is remarkably droll.  I'm not sure how well coalescing works for real

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