Jie, >>> The peak bandwidth I can get is ~ 1.3 GB/s (not >bi-directional), which >>> is almost the same as single rail connections. >>>
That is correct 10Gb/s each port for a max of 20Gb/s. >> >> Assuming you have a 2.5 GT/s pci-express x8 that speed is a >result of the bus >> not being able to keep up with the HCA. Since the bus is >holding even a >> single DDR IB port back you see no improvement with two ports. >> >> >I do connect HCA in a 16x pci-e slot on each node. >However, I am trying to drive 2 ports simultaneously. > >The workstation i am using is Sun Ultra 24, >and the HCA is Mellanox ConnectX MHGH28-XTC. >The data for the HCA and Ultra 24 is > >MHGH28-XTC >IB ports: Dual Copper 4X 20Gb/s >Host Bus: PCIe 2.0 2.5GT/s Peter is right. Your maximum speed given this configuration is 20Gb/s (40Gb/s bi-directional) since you have an 8x adapter in a 2.5GT/s bus. It doesn't matter that you have it in a 16x slot, your adapter is only 8x 2.5GT/s. -arlin _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
