[Beowulf] Intel buys QLogic InfiniBand business

Greg Lindahl lindahl at pbm.com
Mon Jan 30 23:53:18 PST 2012

On Mon, Jan 30, 2012 at 10:04:53AM -0500, Mark Hahn wrote:

> > 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
> applications.

Note also that many of the benchmarks in this analysis weren't run
using MPI -- if I remember correctly, the ib_* commands mentioned use
InfiniBand verbs directly, which means they aren't accellerated on

-- greg

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