the folks on the linux-rdma mailing list can probably share some slides with you about app load over different cards. if you dont get a response, i can drop a few names of people who definitely have the info, but i dont want to do it at large on the list
The last set of slides i can (thinking way back when i was still with qlogic) recall, yes the ipath cards could do 30m mesg/sec whereas the mlnx cards were half to a two thirds lower. this does have an affect on core count traffic, but only under certain application loads mlnx and qlogic made a trade off with their card designs, the qlogic cards have a real high msg/rate, but the rdma bandwidth performance can suffer in certain cases, where as mlnx has a higher rdma bandwidth but a lower mesg rate getting the balance right is a mastery of art. and the tipping point slides easily and with every application it's been a while since i was at qlogic and have forgotten a lot of the sales mumbo... On Fri, Feb 19, 2010 at 1:25 PM, Brian Dobbins <bdobb...@gmail.com> wrote: > > Hi guys, > > I'm beginning to look into configurations for a new cluster and with the > AMD 12-core and Intel 8-core chips 'here' (or coming soonish), I'm curious > if anyone has any data on the effects of the messaging rate of the IB > cards. With a 4-socket node having between 32 and 48 cores, lots of > computing can get done fast, possibly stressing the network. > > I know Qlogic has made a big deal about the InfiniPath adapter's extremely > good message rate in the past... is this still an important issue? How do > the latest Mellanox adapters compare? (Qlogic documents a ~30M messages > processsed per second rate on its QLE7342, but I didn't see a number on the > Mellanox ConnectX-2... and more to the point, do people see this effecting > them?) > > On a similar note, does a dual-port card provide an increase in on-card > processing, or 'just' another link? (The increased bandwidth is certainly > nice, even in a flat switched network, I'm sure!) > > I'm primarily concerned with weather and climate models here - WRF, CAM, > CCSM, etc., and clearly the communication rate will depend to a large degree > on the resolutions used, but any information, even 'gut instincts' people > have are welcome. The more info the merrier. > > Thanks very much, > - Brian > > > > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf > > _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
