Re: ixg(4) performances

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Matthias Drochner <M.Drochner%fz-juelich.de@localhost> wrote:

> > 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
> 
> Wrong -- this means x8.
> 
> > 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
> 
> So it makes sense.

Right, hence the ethernet board can do 5 GbE x 8, but something in front
of it can only do 2.5 GbE x 8.

But 2.5 GbE x 8 means 20 Gb/s, which is much larger than the 2.7 Gb/s I
get.

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost