igb(4) Raising IGB_MAX_RXD ??

[Sean Bruno]

On Thu, 2012-04-19 at 07:09 -0700, Jack Vogel wrote:
> OH, well that's interesting to know, thanks John.
> 
> Jack
> 


Front end box looks pretty happy today at 8k descriptors.

http://people.freebsd.org/~sbruno/igb_8k_stats.txt

Under peak, we're approaching 20MBytes/sec in and out of the
interface.  :-)  Nifty.

-bash-4.2$ netstat 1
            input        (Total)           output
   packets  errs idrops      bytes    packets  errs      bytes colls
     59542     0     0   18189602      59131     0   19884085     0
     58941     0     0   18036651      58673     0   19702671     0
     58790     0     0   18069235      58422     0   19897858     0
     58226     0     0   17948175      57969     0   19648810     0
     58689     0     0   18167855      58479     0   19909843     0
     58633     0     0   17952951      58437     0   19760197     0
     61019     0     0   18779030      60592     0   20394481     0
     56696     0     0   17647407      56552     0   19261155     0
     58853     0     0   18186019      58530     0   19886197     0
     58739     0     0   18314790      58768     0   20165654     0
     58748     0     0   18267243      58539     0   20016668     0
     58672     0     0   17914657      58378     0   19558833     0
     59885     0     0   18332641      59780     0   20239241     0


We're going to crank one server up to 8 igb queues and
hw.igb.max_rxd/txd to 32k and see what blows up.

Sean