On 01/27/2012 02:25 PM, Gilad Shainer wrote: > So I wonder why multiple OEMs decided to use Mellanox for on-board > solutions and no one used the QLogic silicon...
That's a strange argument. What does Intel want? Something to make them more money. In the past that's been integrating functionality into their CPU or support chipsets. In the past that's been sata, usb, memory controller, pci-e controller, and GigE. The cost in transistors and die area seems very relevant to Intel's interests. Anyone have an estimate on how much latency a direct connect to QPI would save vs pci-e? What to motherboard board manufacturers want? Something to make them more money. So that's mostly marketing/reputation, pricing, and whatever they can do to differentiate themselves. If buying a $150 IB chip lets them charge $400 more then it's a win, assuming they spend less than $250 of R&D to add it to the motherboard. I doubt the difference in transistors or a few watts would be a big deal either way. >> Also, keep in mind that Intel's benchmarking group in Moscow has a >> lot of experience with benchmarking real apps for bids using >> TrueScale head-to-head >> against other HCAs, and I wouldn't be surprised if it was the case that TrueScale >> QDR is faster than that other company's FDR on many real codes, > > > Surprise surprise... this is no more than FUD. If you have real > numbers to back it up please send. If it was so great, how come more > people decided to use the Mellanox solutions? If QLogic was doing so > great with their solution, I would guess they would not be selling the > IB business... FUD = Fear, Uncertainty, and Doubt. Doesn't sound like FUD to me. More like a cheap attack on Greg, I think we (the mailing list) can do better. I've personally compared several generations of Myrinet and Infinipath to allegedly faster Mellanox adapters. Mellanox hasn't won yet, but I've not compared QDR or FDR yet. With that said the reason I run the benchmarks to find the best solution and it might well be Mellanox next time. It would be irresponsible to recommend Mellanox cluster provide just pick mellanox FDR over Qlogic QDR just because of the spec sheet. Of course recommending Qlogic over Mellanox without quantifying real world performance would be just as irresponsible. Maybe we could have a few less attacks, complaining and hand waving and more useful information? IMO Greg never came across as a commercial (which beowulf list isn't an appropriate place for), but does regularly contribute useful info. Arguing market share as proof of performance superiority is just silly. Speaking of which, you said: There is some add latency due to the 66/64 new encoding, but overall latency is lower than QDR. MPI is below 1us. I googled for additional information, looked around the Mellanox website, and couldn't find anything. Is that above number relevant to HPC folks running clusters? Does it involve a switch? If not realistic are there any realistic numbers available? _______________________________________________ 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
