Yes, I'm pleased that several companies have adopted message rate as a metric, although I'm also sad that some have gamed the benchmark with message coalescing.
N1/2 was intended to say something about the shape of the bandwidth-by-message-size curve. The smaller it is, the farther you can go with strong scaling. Historically I had lobbied for people to publish N1/2 Linpack numbers, never got anywhere with that. N1/2 and message rate were my attempt to update the usual "bandwidth and latency" microbenchmarks to something with more meaning. On Wed, Jun 01, 2016 at 03:29:51PM -0700, Holger Fröning wrote: > Greg, we all do remember n/2 (actually I still teach about it). If I remember > right, PathScale introduced the message rate metric, too, and that actually > became vey popular. Personally, I prefer this one as it is very descriptive. > Personally, I found it difficult to compare different technologies using n/2. > > Holger > > > > On 01 Jun 2016, at 15:18, Greg Lindahl <[email protected]> wrote: > > > > On Wed, Jun 01, 2016 at 03:25:22PM -0400, Andrew Piskorski wrote: > > > >> You mean GAMMA (Genoa Active Message MAchine): > >> > >> http://www.disi.unige.it/project/gamma/ > >> http://www.linux-mag.com/id/7253/ > >> http://www.beowulf.org/pipermail/beowulf/2006-February/014846.html > > > > I wonder how their flow control scheme of static partitioning of the > > receive queue scales to more modern hardware? > > > > Oh, and I'm thrilled that they show the N_1/2 packet size! (the size > > where bandwidth reaches 1/2 of the peak.) That's a number PathScale > > published, but it never became popular with other folks doing > > performance testing. > > > > -- greg > > > > > > _______________________________________________ > > Beowulf mailing list, [email protected] sponsored by Penguin Computing > > To change your subscription (digest mode or unsubscribe) visit > > http://www.beowulf.org/mailman/listinfo/beowulf _______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
