Hi all, thanks again for the wealth of information.
Now, given that I am not interested in transporting files over the IB network but I am doing parallel calculations, I would have thought that the latency here is more important than the speed? Thus, if FDR has a higher latency than QDR, does that mean my performance is decreasing when I am running a calculation between nodes? For those of you who are into Chemistry code: I am using VASP, cp2k, quantum espresso and cpmd mainly. All of that is plain wave code. All the best from a wet London Jörg On Mittwoch 29 Oktober 2014 Prentice Bisbal wrote: > On 10/28/2014 04:43 PM, Mark Hahn wrote: > > On Tue, 28 Oct 2014, John Hearns wrote: > >> Here is a very good post from Glenn Lockwood regarding FDR versus > >> dual-rail QDR: > >> > >> http://glennklockwood.blogspot.co.uk/2013/05/fdr-infiniband-vs-dual-rail > >> -qdr.html > > > > indeed, very nice. though also quite surprising - is it known that > > FDR is so terrible for latency? seems astonishing to me. > > Yes, it was known to me. I had already known that FDR was worse than QDR > for latency, but I don't remember my source. I don't know if I'd > characterize it as "so terrible", though. -- ************************************************************* Dr. Jörg Saßmannshausen, MRSC University College London Department of Chemistry Gordon Street London WC1H 0AJ email: j.sassmannshau...@ucl.ac.uk web: http://sassy.formativ.net Please avoid sending me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html
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