On Fri, Mar 23, 2007 at 11:53:14AM -0700, Gilad Shainer wrote: > and not only on pure latency or pure bandwidth. Qlogic till recently (*) > had the lowest latency number but when it comes to application, the CPU > overhead is too high.
QLogic's overhead is lower than Mellanox, how low do you want it to be? Please see http://www.pathscale.com/pdf/overhead_and_app_perf.pdf This shows the MPI overhead per byte transferred, as measured by Doug at Sandia in 2005. How can ours be lower? The InfiniBand APIs are unnecessarily complicated, and are a poor match to MPI compared to everyone elses APIs: MX, Tports, InfiniPath's PSM. The next slide shows a graph of the LS-Dyna results recently submitted to topcrunch.org, showing that InfiniPath SDR beats Mellanox DDR on the neon_refined_revised problem, both running on 3.0 Ghz Woodcrest dual/dual nodes. I look forward to showing the same advantage vs ConnectX, whenever it's actually available. -- greg (p.s. ggv has issues with the fonts in this pdf, so try xpdf or (yech) acroread instead.) _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
