> On Friday, August 29, 2014 11:51, Emmanuel Dreyfus wrote: > > On Fri, Aug 29, 2014 at 08:48:51AM -0400, Terry Moore wrote: > > Still, you should check whether you have the right number of the right > > generation of PCIe lanes connected to the ixg. > > I found this, but the result does not make sense: negociated > max ... > > Link Capabilities Ragister (0xAC): 0x00027482 > bits 3:0 Supprted Link speed: 0010 = 5 GbE and 2.5 GbE speed supported > bits 9:4 Max link width: 001000 = x4 > bits 14:12 L0s exit lattency: 101 = 1 µs - 2 µs bits 17:15 L1 Exit > lattency: 011 = 4 µs - 8 µs > > Link Status Register (0xB2): 0x1081 > bits 3:0 Current Link speed: 0001 = 2.5 GbE PCIe link > bits 9:4 Negociated link width: 001000 = x8
I think there's a typo in the docs. In the PCIe spec, it says (for Link Capabilities Register, table 7-15): 001000b is x8. But it's running at gen1. I strongly suspect that the benchmark case was gen2 (since the ixg is capable of it). Is the ixg in an expansion slot or integrated onto the main board? --Terry